Different stages of liver damageFatty liver, also known as fatty liver disease (FLD), steatorrhoeic hepatosis, or steatosis hepatitis, is a reversible condition where large vacuoles of triglyceride fat accumulate in liver cells via the process of steatosis.

Despite having multiple causes, fatty liver can be considered a single disease that occurs worldwide in those with excessive alcohol intake and those who are obese (with or without effects of insulin resistance). The condition is also associated with other diseases that influence fat metabolism[1]. Morphologically it is difficult to distinguish alcoholic FLD from non alcoholic FLD and both show micro-vesicular and macrovesicular fatty changes at different stages.

In this stage liver cells are filled with multiple fat droplets that do not displace centrally located nucleus. In the late stages, the size of the vacuoles increases pushing the nucleus to the periphery of the cell giving characteristic signet ring appearance - macrovesicular fatty change. These vesicles are well delineated and optically "empty" because fats dissolve during tissue processing.

Large vacuoles may coalesce, producing fatty cysts - which are irreversible lesions. Macrovesicular steatosis is the most common form and is typically associated with alcohol, diabetes, obesity and corticosteroids. Acute fatty liver of pregnancy and Reye's syndrome are examples of severe liver disease caused by microvesicular fatty change[4]. The diagnosis of steatosis is made when fat in the liver exceeds 5–10% by weight[5][6][1].

Mechanism leading to hepatic steatosisDefects in fat metabolism are responsible for pathogenesis of FLD which may be due to imbalance in energy consumption and its combustion resulting in lipid storage or can be a consequence of peripheral resistance to insulin, whereby the transport of fatty acids from adipose tissue to the liver is increased[7][1].

Impairment or inhibition of receptor molecules (PPAR-α, PPAR-γ and SREBP1) that control the enzymes responsible for the oxidation and synthesis of fatty acids appears to contribute towards fat accumulation.

In addition alcoholism is known to damage mitochondria and other cellular structure further impairing cellular energy mechanism. On the other hand non alcoholic FLD may begin as excess of unmetabolised energy in liver cells. Hepatic steatosis is considered reversible and to some extent nonprogressive if there is cessation or removal of underlying cause.

Severe fatty liver is sometimes accompanied by inflammation, a situation that is referred to as steatohepatitis. Progression to alcoholic steatohepatitis (ASH) or non-alcoholic steatohepatitis (NASH) depend on persistence or severity of inciting cause. Pathological lesions in both conditions are similar.

However, the extent of inflammatory response varies widely and does not always correlate with degree of fat accumulation. Steatosis (retention of lipid) and onset of steatohepatitis may represent successive stages in FLD progression[8].

Liver with extensive inflammation and high degree of steatosis often progresses to more severe forms of the disease[9]. Hepatocyte ballooning and hepatocyte necrosis of varying degree are often present at this stage. Liver cell death and inflammatory responses lead to the activation of stellate cells which play a pivotal role in hepatic fibrosis.

The extent of fibrosis varies widely. Perisinusoidal fibrosis is most common, especially in adults, and predominates in zone 3 around the terminal hepatic veins[10].

The progression to cirrhosis may be influenced by the amount of fat and degree of steatohepatitis and by a variety of other sensitizing factors. In alcoholic FLD the transition to cirrhosis related to continued alcohol consumption is well documented but the process involved in non-alcoholic FLD is less clear.

‡ Criteria for nonalcoholic fatty liver disease:consumption of ethanol less than 20g/day for woman and 30g/day for man[11]

Most individuals are asymptomatic and are usually discovered incidentally because of abnormal liver function tests or hepatomegaly noted in unrelated medical condition. Elevated liver biochemistry is found in 50% of patients with simple steatosis[12]. The serum ALT level usually is greater than the AST level in non-alcoholic variant and the opposite in alcoholic FLD ( AST:ALT more than 2:1).

Imaging studies are often obtained during evaluation process. Ultrasonography reveals a "bright" liver with increased echogenicity.

Medical imaging can aid in diagnosis of fatty liver; fatty livers have lower density than spleen on computed tomography (CT) and fat appears bright in T1-weighted magnetic resonance images (MRIs). No medical imagery, however, is able to distinguish simple steatosis from advanced NASH. Histological diagnosis by liver biopsy is sought when assessment of severity is indicated.

[edit] Treatment and preventionThe treatment of fatty liver depends on what is causing it, and generally, treating the underlying cause will reverse the process of steatosis if implemented at early stage.

Complication

Up to 10% of cirrhotic alcoholic FLD will develop hepatocellular carcinoma. Overall incidence of liver cancer in non-alcoholic FLD has not yet been quantified, but the association is well established[13].

Epidemiology

The prevalence of FLD in the general population ranges from 10% to 24% in various countries[2]. However, the condition is observed in up to 75% of obese people, 35% of whom will progress to non-alcoholic FLD[14], despite no evidence of excessive alcohol consumption. FLD is the most common cause of abnormal liver function test in the US[2].

Hispanic-Americans and European-Americans have higher frequencies of unexplained serum aminotransferase elevations than those reported in African-Americans (http://www.webmd.com/digestive-disorders/news/20080925/fatty-liver-disease-genes-affect-risk), but prevalence of FLD among different racial groups is not known.

Hepatitis C is an infectious disease affecting the liver, caused by the hepatitis C virus (HCV).[1] The infection is often asymptomatic, but once established, chronic infection can progress to scarring of the liver (fibrosis), and advanced scarring (cirrhosis). In some cases, those with cirrhosis will go on to develop liver failure or other complications of cirrhosis, including liver cancer.[1]

The hepatitis C virus (HCV) is spread by blood-to-blood contact. Most people have few symptoms after the initial infection, yet the virus persists in the liver in about 80% of those infected. Persistent infection can be treated with medication, such as interferon and ribavirin, and currently over half are cured overall. Those who develop cirrhosis or liver cancer may require a liver transplant, although the virus generally recurs after transplantion.

An estimated 150-200 million people worldwide are infected with hepatitis C. Apart from humans, it only infects chimpanzees. No vaccine against hepatitis C is available. The existence of hepatitis C (originally "non-A non-B hepatitis") was postulated in the 1970s and proved conclusively in 1989. It is one of five known hepatitis viruses: A, B, C, D, and E.

Acute hepatitis C refers to the first 6 months after infection with HCV. Between 60% to 70% of people infected develop no symptoms during the acute phase. In the minority of patients who experience acute phase symptoms, they are generally mild and nonspecific, and rarely lead to a specific diagnosis of hepatitis C. Symptoms of acute hepatitis C infection include decreased appetite, fatigue, abdominal pain, jaundice, itching, and flu-like symptoms.

The hepatitis C virus is usually detectable in the blood within one to three weeks after infection by PCR, and antibodies to the virus are generally detectable within 3 to 15 weeks. Approximately 15-40% of persons infected with HCV clear the virus from their bodies during the acute phase as shown by normalization in liver function tests (LFTs) such as alanine transaminase (ALT) & aspartate transaminase (AST) normalization, as well as plasma HCV-RNA clearance (this is known as spontaneous viral clearance). The remaining 60-85% of patients infected with HCV develop chronic hepatitis C, i.e., infection lasting more than 6 months.[2][3][4]

Previous practice was to not treat acute infections to see if the person would spontaneously clear; recent studies have shown that treatment during the acute phase of genotype 1 infections has a greater than 90% success rate with half the treatment time required for chronic infections.[5]

Chronic

Chronic hepatitis C is defined as infection with the hepatitis C virus persisting for more than six months. Clinically, it is often asymptomatic (without symptoms) and it is mostly discovered accidentally.

The natural course of chronic hepatitis C varies considerably from one person to another. Virtually all people infected with HCV have evidence of inflammation on liver biopsy, however, the rate of progression of liver scarring (fibrosis) shows significant variability among individuals. Recent data suggest that among untreated patients, roughly one-third progress to liver cirrhosis in less than 20 years. Another third progress to cirrhosis within 30 years. The remainder of patients appear to progress so slowly that they are unlikely to develop cirrhosis within their lifetimes.

Factors that have been reported to influence the rate of HCV disease progression include age (increasing age associated with more rapid progression), gender (males have more rapid disease progression than females), alcohol consumption (associated with an increased rate of disease progression), HIV coinfection (associated with a markedly increased rate of disease progression), and fatty liver (the presence of fat in liver cells has been associated with an increased rate of disease progression).

Symptoms specifically suggestive of liver disease are typically absent until substantial scarring of the liver has occurred. However, hepatitis C is a systemic disease and patients may experience a wide spectrum of clinical manifestations ranging from an absence of symptoms to a more symptomatic illness prior to the development of advanced liver disease. Generalized signs and symptoms associated with chronic hepatitis C include fatigue, flu-like symptoms, joint pains, itching, sleep disturbances, appetite changes, nausea, and depression.

Once chronic hepatitis C has progressed to cirrhosis, signs and symptoms may appear that are generally caused by either decreased liver function or increased pressure in the liver circulation, a condition known as portal hypertension. Possible signs and symptoms of liver cirrhosis include ascites (accumulation of fluid in the abdomen), bruising and bleeding tendency, varices (enlarged veins, especially in the stomach and esophagus), jaundice, and a syndrome of cognitive impairment known as hepatic encephalopathy. Hepatic encephalopathy is due to the accumulation of ammonia and other substances normally cleared by a healthy liver.

Liver function tests show variable elevation of ALT and AST. Periodically they might show normal results. Usually prothrombin and albumin results are normal, but may become abnormal, once cirrhosis has developed. The level of elevation of liver tests do not correlate well with the amount of liver injury on biopsy. Viral genotype and viral load also do not correlate with the amount of liver injury. Liver biopsy is the best test to determine the amount of scarring and inflammation. Radiographic studies such as ultrasound or CT scan do not show liver injury until it is fairly advanced.

Chronic hepatitis C, more than other forms of hepatitis, can be associated with extrahepatic manifestations associated with the presence of HCV such as porphyria cutanea tarda, cryoglobulinemia (a form of small-vessel vasculitis)[6] and glomerulonephritis (inflammation of the kidney), specifically membranoproliferative glomerulonephritis (MPGN).[7] Hepatitis C is also rarely associated with sicca syndrome (an autoimmune disorder), thrombocytopenia, lichen planus, diabetes mellitus and with B-cell lymphoproliferative disorders.[8]

Virology

Hepatitis C infection in the US by source. (CDC,n.d.[dead link])Main article: Hepatitis C virusThe Hepatitis C virus (HCV) is a small (50 nm in size), enveloped, single-stranded, positive sense RNA virus. It is the only known member of the hepacivirus genus in the family Flaviviridae. There are six major genotypes of the hepatitis C virus, which are indicated numerically (e.g., genotype 1, genotype 2, etc.).

The hepatitis C virus (HCV) is transmitted by blood-to-blood contact. In developed countries, it is estimated that 90% of persons with chronic HCV infection were infected through transfusion of unscreened blood or blood products or via injecting drug use or, by inhalational drug use. Inhalational drug usage (snorting) has evolved into one of the most common means of infection in the United States. In developing countries, the primary sources of HCV infection are unsterilized injection equipment and infusion of inadequately screened blood and blood products. There has not been a documented transfusion-related case of hepatitis C in the United States for over a decade as the blood supply is vigorously screened with both EIA and PCR technologies.

Although injection drug use and inhalational drugs are the most common routes of HCV infection, any practice, activity, or situation that involves blood-to-blood exposure can potentially be a source of HCV infection. The virus may be sexually transmitted, although this is rare, and usually only occurs when an STD (like HIV) is also present and makes blood contact more likely.[9].

[edit] TransmissionSeveral activities and practices were initially identified as potential sources of exposure to the hepatitis C virus. More recent studies question this route of transmission. Currently it is felt to be a means of rare transmission of hepatitis C infection.

Injection drug use Those who currently use or have used drug injection as their delivery route for illicit drugs are at increased risk for getting hepatitis C because they may be sharing needles or other drug paraphernalia (includes cookers, cotton, spoons, water, etc.), which may be contaminated with HCV-infected blood. An estimated 60% to 80% of intravenous recreational drug users in the United States have been infected with HCV.[10] Harm reduction strategies are encouraged in many countries to reduce the spread of hepatitis C, through education, provision of clean needles and syringes, and safer injecting techniques.

Drug use by nasal inhalation (Drugs that are "snorted") Transmission of HCV is possible through the nasal inhalation (insuffulation) of drugs when straws (containing even trace amounts of mucus and blood) are shared among users.[11]

Blood products Blood transfusion, blood products, or organ transplantation prior to implementation of HCV screening (in the U.S., this would refer to procedures prior to 1992) is a decreasing risk factor for hepatitis C.

The virus was first isolated in 1989 and reliable tests to screen for the virus were not available until 1992. Therefore, those who received blood or blood products prior to the implementation of screening the blood supply for HCV may have been exposed to the virus. Blood products include clotting factors (taken by hemophiliacs), immunoglobulin, Rhogam, platelets, and plasma. In 2001, the Centers for Disease Control and Prevention reported that the risk of HCV infection from a unit of transfused blood in the United States is less than one per million transfused units.

Iatrogenic medical or dental exposure People can be exposed to HCV via inadequately or improperly sterilized medical or dental equipment. Equipment that may harbor contaminated blood if improperly sterilized includes needles or syringes, hemodialysis equipment, oral hygiene instruments, and jet air guns, etc. Scrupulous use of appropriate sterilization techniques and proper disposal of used equipment can reduce the risk of iatrogenic exposure to HCV to virtually zero.

Occupational exposure to blood

Medical and dental personnel, first responders (e.g., firefighters, paramedics, emergency medical technicians, law enforcement officers), and military combat personnel can be exposed to HCV through accidental exposure to blood through accidental needlesticks or blood spatter to the eyes or open wounds. Universal precautions to protect against such accidental exposures significantly reduce the risk of exposure to HCV.

Recreational exposure to blood

Contact sports and other activities, such as "slam dancing" that may result in accidental blood-to-blood exposure are potential sources of exposure to HCV.[12]

Sexual exposure

Sexual transmission of HCV is considered to be rare. Studies show the risk of sexual transmission in heterosexual, monogamous relationships is extremely rare or even null.[13][14] The CDC does not recommend the use of condoms between long-term monogamous discordant couples (where one partner is positive and the other is negative).[15] However, because of the high prevalence of hepatitis C, this small risk may translate into a non-trivial number of cases transmitted by sexual routes. Vaginal penetrative sex is believed to have a lower risk of transmission than sexual practices that involve higher levels of trauma to anogenital mucosa (anal penetrative sex, fisting, use of sex toys).[16]

Body piercings and tattoos

Tattooing dyes, ink pots, stylets and piercing implements can transmit HCV-infected blood from one person to another if proper sterilization techniques are not followed. Tattoos or piercings performed before the mid 1980s, "underground," or non-professionally are of particular concern since sterile techniques in such settings may have been or be insufficient to prevent disease.

Despite these risks, it is rare for tattoos to be directly associated with HCV infection and the U.S. Centers for Disease Control and Prevention's position on this subject states that, "no data exist in the United States indicating that persons with exposures to tattooing alone are at increased risk for HCV infection."[17]

Shared personal care items

Personal care items such as razors, toothbrushes, cuticle scissors, and other manicuring or pedicuring equipment can easily be contaminated with blood. Sharing such items can potentially lead to exposure to HCV. Appropriate caution should be taken regarding any medical condition which results in bleeding such as canker sores, cold sores, and immediately after flossing.

HCV is not spread through casual contact such as hugging, kissing, or sharing eating or cooking utensils.[18]

[edit] Vertical transmission

Vertical transmission refers to the transmission of a communicable disease from an infected mother to her child during the birth process. Mother-to-child transmission of hepatitis C has been well described, but occurs relatively infrequently. Transmission occurs only among women who are HCV RNA positive at the time of delivery; the risk of transmission in this setting is approximately 6 out of 100. Among women who are both HCV and HIV positive at the time of delivery, the risk of transmitting HCV is increased to approximately 25 out of 100.

The risk of vertical transmission of HCV does not appear to be associated with method of delivery or breastfeeding.

[edit] Diagnosis

Cirrhosis of the liver and liver cancer may ensue from hepatitis C. Serologic profile of Hepatitis C infectionThe diagnosis of "hepatitis C" is rarely made during the acute phase of the disease because the majority of people infected experience no symptoms during this phase of the disease. Those who do experience acute phase symptoms are rarely ill enough to seek medical attention. The diagnosis of chronic phase hepatitis C is also challenging due to the absence or lack of specificity of symptoms until advanced liver disease develops, which may not occur until decades into the disease.

Chronic hepatitis C may be suspected on the basis of the medical history (particularly if there is any history of IV drug abuse or inhaled substance usage such as cocaine), a history of piercings or tattoos, unexplained symptoms, or abnormal liver enzymes or liver function tests found during routine blood testing. Occasionally, hepatitis C is diagnosed as a result of targeted screening such as blood donation (blood donors are screened for numerous blood-borne diseases including hepatitis C) or contact tracing.

Hepatitis C testing begins with serological blood tests used to detect antibodies to HCV. Anti-HCV antibodies can be detected in 80% of patients within 15 weeks after exposure, in >90% within 5 months after exposure, and in >97% by 6 months after exposure. Overall, HCV antibody tests have a strong positive predictive value for exposure to the hepatitis C virus, but may miss patients who have not yet developed antibodies (seroconversion), or have an insufficient level of antibodies to detect. Rarely, people infected with HCV never develop antibodies to the virus and therefore, never test positive using HCV antibody screening. Because of this possibility, RNA testing (see nucleic acid testing methods below) should be considered when antibody testing is negative but suspicion of hepatitis C is high (e.g. because of elevated transaminases in someone with risk factors for hepatitis C).

Anti-HCV antibodies indicate exposure to the virus, but cannot determine if ongoing infection is present. All persons with positive anti-HCV antibody tests must undergo additional testing for the presence of the hepatitis C virus itself to determine whether current infection is present. The presence of the virus is tested for using molecular nucleic acid testing methods such as polymerase chain reaction (PCR), transcription mediated amplification (TMA), or branched DNA (b-DNA). All HCV nucleic acid molecular tests have the capacity to detect not only whether the virus is present, but also to measure the amount of virus present in the blood (the HCV viral load). The HCV viral load is an important factor in determining the probability of response to interferon-based therapy, but does not indicate disease severity nor the likelihood of disease progression.

In people with confirmed HCV infection, genotype testing is generally recommended. HCV genotype testing is used to determine the required length and potential response to interferon-based therap

TreatmentThere is a very small chance of clearing the virus spontaneously in chronic HCV carriers (0.5 to 0.74% per year),[19][20] however, the majority of patients with chronic hepatitis C will not clear it without treatment.

Current treatment is a combination of pegylated interferon alpha (brand names Pegasys and PEG-Intron) and the antiviral drug ribavirin for a period of 24 or 48 weeks, depending on genotype.

Indications for treatment include patients with proven hepatitis C virus infection and persistent abnormal liver function tests. Sustained cure rates (sustained viral response) of 75% or better occur in people with genotypes HCV 2 and 3 in 24 weeks of treatment,[21] about 50% in those with genotype 1 with 48 weeks of treatment and 65% for those with genotype 4 in 48 weeks of treatment.

About 80% of hepatitis C patients in the United States have genotype 1. Genotype 4 is more common in the Middle East and Africa. Should treatment with pegylated ribivirin-interferon not return a 2-log viral reduction or complete clearance of RNA (termed early virological response) after 12 weeks for genotype 1, the chance of treatment success is less than 1%. Early virological response is typically not tested for in non-genotype 1 patients, as the chances of attaining it are greater than 90%. T

he mechanism of action is not entirely clear, because even patients who appear to have had a sustained virological response still have actively replicating virus in their liver and peripheral blood mononuclear cells.[22]

The evidence for treatment in genotype 6 disease is currently sparse, and the evidence that exists is for 48 weeks of treatment at the same doses as are used for genotype 1 disease.[23] Physicians considering shorter durations of treatment (e.g., 24 weeks) should do so within the context of a clinical trial.

Treatment during the acute infection phase has much higher success rates (greater than 90%) with a shorter duration of treatment; however, this must be balanced against the 15-40% chance of spontaneous clearance without treatment (see Acute Hepatitis C section above).

Those with low initial viral loads respond much better to treatment than those with higher viral loads (greater than 400,000 IU/mL). Current combination therapy is usually supervised by physicians in the fields of gastroenterology, hepatology or infectious disease.

The treatment may be physically demanding, particularly for those with a prior history of drug or alcohol abuse. It can qualify for temporary disability in some cases.

A substantial proportion of patients will experience a panoply of side effects ranging from a 'flu-like' syndrome (the most common, experienced for a few days after the weekly injection of interferon) to severe adverse events including anemia, cardiovascular events and psychiatric problems such as suicide or suicidal ideation. The latter are exacerbated by the general physiological stress experienced by the patient.

Current guidelines strongly recommend that hepatitis C patients be vaccinated for hepatitis A and B if they have not yet been exposed to these viruses, as infection with a second virus could worsen their liver disease.

If a pregnant woman has risk factors for hepatitis C, she should be tested for antibodies against HCV. About 4% infants born to HCV infected women become infected. There is no treatment that can prevent this from happening. There is a high chance of the baby ridding the HCV in the first 12 months.

In a mother that also has HIV, the rate of transmission can be as high as 19%. There are currently no data to determine whether antiviral therapy reduces perinatal transmission. Ribavirin and interferons are contraindicated during pregnancy. However, avoiding fetal scalp monitoring and prolonged labor after rupture of membranes may reduce the risk of transmission to the infant.

HCV antibodies from the mother may persist in infants until 15 months of age. If an early diagnosis is desired, testing for HCV RNA can be performed between the ages of 2 and 6 months, with a repeat test done independent of the first test result. If a later diagnosis is preferred, an anti-HCV test can performed after 15 months of age. Most infants infected with HCV at the time of birth have no symptoms and do well during childhood. There is no evidence that breast-feeding spreads HCV. To be cautious, an infected mother should avoid breastfeeding if her nipples are cracked and bleeding.[24]

Alternative therapies

Several alternative therapies aim to maintain liver functionality, rather than treat the virus itself, thereby slowing the course of the disease to retain quality of life. As an example, extract of Silybum marianum and Sho-saiko-to are sold for their HCV related effects; the first is said to provide some generic help to hepatic functions, and the second claims to aid in liver health and provide some antiviral effects.[25]. Unfortunately, there has never been any verifiable histologic or virologic benefit demonstrated with any of the alternative therapies.

Experimental treatments

The drug viramidine, which is a prodrug of ribavirin that has better targeting for the liver, and therefore may be more effective against hepatitis C for a given tolerated dose, is in phase III experimental trials against hepatitis C. It will be used in conjunction with interferons, in the same manner as ribavirin. However, this drug is not expected to be active against ribavirin-resistant strains, and the use of the drug against infections which have already failed ribavirin/interferon treatment, is unproven.

There are new drugs under development like the protease inhibitors (including VX 950) and polymerase inhibitors (such as NM 283), but development of some of these is still in the early phase. VX 950, also known as Telaprevir[26] is currently in Phase 3 Trials. [27][28] One protease inhibitor, BILN 2061, had to be discontinued due to safety problems early in the clinical testing. Some more modern new drugs that provide some support in treating HCV are Albuferon, Zadaxin, and DAPY.[citation needed] Antisense phosphorothioate oligos have been targeted to hepatitis C.[29] Antisense Morpholino oligos have shown promise in preclinical studies[30] however, they were found to cause a limited viral load reduction.

Immunoglobulins against the hepatitis C virus exist and newer types are under development. Thus far, their roles have been unclear as they have not been shown to help in clearing chronic infection or in the prevention of infection with acute exposures (e.g. needlesticks). They do have a limited role in transplant patients.

In addition to the standard treatment with interferon and ribavirin, some studies have shown higher success rates when the antiviral drug amantadine (Symmetrel) is added to the regimen. Sometimes called "triple therapy", it involves the addition of 100 mg of amantadine twice a day. Studies indicate that this may be especially helpful for "nonresponders" - patients who have not been successful in previous treatments using interferon and ribavirin only.[31] Currently, amantadine is not approved for treatment of Hepatitis C, and studies are ongoing to determine when it is most likely to benefit the patient. Followup studies have shown no benefit to adding this drug and currently it is not commonly used by experienced hepatologists.

Epidemiology

Prevalence of Hepatitis C worldwide (1999, WHO)Hepatitis C infects nearly 200 million people worldwide and 4 million in the United States.[32][33] There are about 35,000 to 185,000 new cases a year in the United States, and hepatitis C is the leading cause of liver transplant in the USA. Co-infection with HIV is common and rates among HIV positive populations are higher. 10,000-20,000 deaths a year in the United States are from HCV; expectations are that this mortality rate will increase, as those who were infected by transfusion before HCV testing become apparent. A survey conducted in California showed prevalence of up to 34% among prison inmates;[34] 82% of subjects diagnosed with hepatitis C have previously been in jail,[35] and transmission while in prison is well described.[36]

Prevalence is higher in some countries in Africa and Asia.[37] Egypt has the highest seroprevalence for HCV, up to 20% in some areas. There is a hypothesis that the high prevalence is linked to a now-discontinued mass-treatment campaign for schistosomiasis, which is endemic in that country.[38] Regardless of how the epidemic started, a high rate of HCV transmission continues in Egypt, both iatrogenically and within the community and household.

Co-infection with HIV

Approximately 350,000, or 35% of patients in the USA infected with HIV are also infected with the hepatitis C virus, mainly because both viruses are blood-borne and present in similar populations. In other countries co-infection is less common, and this is possibly related to differing drug policies.[citation needed] HCV is the leading cause of chronic liver disease in the USA. It has been demonstrated in clinical studies that HIV infection causes a more rapid progression of chronic hepatitis C to cirrhosis and liver failure. This is not to say treatment is not an option for those living with co-infection.

[edit] PreventionThe following guidelines will prevent infection with the hepatitis C virus, which is spread by blood:

Avoid sharing drug needles or any other drug paraphernalia including works for injection or bills or straws Avoid unsanitary tattoo methods Avoid unsanitary body piercing methods Avoid unsanitary acupuncture Avoid needlestick injury Avoid sharing personal items such as toothbrushes, razors, and nail clippers. Use latex condoms correctly and every time you have sex if not in a long-term monogamous relationship[39] Proponents of harm reduction believe that strategies such as the provision of new needles and syringes, and education about safer drug injection procedures, greatly decreases the risk of hepatitis C spreading between injecting drug users.

No vaccine protects against contracting hepatitis C, or helps to treat it. Vaccines are under development and some have shown encouraging results.[40]

History

In the mid 1970s, Harvey J. Alter, Chief of the Infectious Disease Section in the Department of Transfusion Medicine at the National Institutes of Health, and his research team demonstrated that most post-transfusion hepatitis cases were not due to hepatitis A or B viruses. Despite this discovery, international research efforts to identify the virus, initially called non-A, non-B hepatitis (NANBH), failed for the next decade. In 1987, Michael Houghton, Qui-Lim Choo, and George Kuo at Chiron Corporation, collaborating with Dr. D.W. Bradley from CDC, utilized a novel molecular cloning approach to identify the unknown organism.[41] In 1988, the virus was confirmed by Alter by verifying its presence in a panel of NANBH specimens. In April of 1989, the discovery of the virus, re-named hepatitis C virus (HCV), was published in two articles in the journal Science. [42][43]

Chiron filed for several patents on the virus and its diagnosis.[44] A competing patent application by the CDC was dropped in 1990 after Chiron paid $1.9 million to the CDC and $337,500 to Bradley. In 1994 Bradley sued Chiron, seeking to invalidate the patent, have himself included as a co-inventor, and receive damages and royalty income. He dropped the suit in 1998 after losing before an appeals court.[45]

In 2000, Drs. Alter and Houghton were honored with the Lasker Award for Clinical Medical Research for "pioneering work leading to the discovery of the virus that causes hepatitis C and the development of screening methods that reduced the risk of blood transfusion-associated hepatitis in the U.S. from 30% in 1970 to virtually zero in 2000."[46]

In 2004 Chiron held 100 patents in 20 countries related to hepatitis C and had successfully sued many companies for infringement. Scientists and competitors have complained that the company hinders the fight against hepatitis C by demanding too much money for its technology.[45]

CDC's Hepatitis C Fact Sheet Hepatitis C at the Open Directory Project "What I need to know about Hepatitis C". National Digestive Diseases Information Clearinghouse. May 2004. http://digestive.niddk.nih.gov/ddiseases/pubs/hepc_ez/. Organizations and programsNational Hepatitis C Program U.S. Department of Veterans Affairs Hepatitis Australia Hepatitis Australia Hepatitis C homepage of the UK National Health Service National Canadian Research Training Program in Hepatitis C Training program funded by the Canadian Institutes of Health Research.

Tuesday, April 28, 2009

Abstract:Wilkinson contends that economic inequality reduces the health and life expectancy of the whole population but his argument does not make sense within its own evolutionary framework.

Recent evolutionary psychological theory suggests that the human brain, adapted to the ancestral environment, has difficulty comprehending and dealing with entities and situations that did not exist in the ancestral environment and that general intelligence evolved as a domain-specific adaptation to solve evolutionarily novel problems.

Since most dangers to health in the contemporary society are evolutionarily novel, it follows that more intelligent individuals are better able to recognize and deal with such dangers and live longer.

Consistent with the theory, the macro-level analyses show that income inequality and economic development have no effect on life expectancy at birth, infant mortality and age-specific mortality net of average intelligence quotient (IQ) in 126 countries.

They also show that an average IQ has a very large and significant effect on population health but not in the evolutionarily familiar sub-Saharan Africa. At the micro level, the General Social Survey data show that, while both income and intelligence have independent positive effects on self-reported health, intelligence has a stronger effect than income.

The data collectively suggest that individuals in wealthier and more egalitarian societies live longer and stay healthier, not because they are wealthier or more egalitarian but because they are more intelligent. No way!

Document Type: Research article DOI: 10.1348/135910705X69842Affiliations: 1: Interdisciplinary Institute of Management, London School of Economics and Political Science, UK

Dear Ms Gibson of London School of Economics:Re: It is not IQ It is the biological and physical environment Stupid! That impacts the health of nations.

I read with interest and some level of disgust by the assumption of IQ as defined by Western Culture to define the competence of Africans and especially Ethiopians as mentioned in this article.

I would like to challenge the Cultural and Competency IQ of the author of this rather ridiculous and racist author. We should question the integrity and implication of such rather depressing and outmoded research and generalizations.

Imagine an Ethiopian High School Student administering a literature IQ test to all the Nobel Literature laureates on Quine and Semina Work in Amharic and in Geez even better and assessing their Quine IQ status.

I am sure all of them will score 00.00 let alone this rather racist and demented Eco-psychologist of the LSE will surface on the Quine IQ square. Just imagine the class discussion on a paper presented by such Ethiopian High School student on the performance of Western Noble laureates of literature. This is the analogy of this rather disturbing paper presented to us.

If you then gave the same Geez or Amharic Quine IQ test to the rest of the world and mapped the Quine IQ you will be shocked to realize that world IQ may not even reach 1% and that will be a tragedy. In effect, this is the tragedy of this paper.

I am a physician and public health scientist who have studied child development (physical and cognitive development) and evaluated research material on child survival across developing an developed countries for the past 25 years. My MPH thesis was on "Evaluating Mother and Child Health Services in Developing and Developed countries with a focus on Perinatal Survival of children in developing and developed countries.

My research indicates that child survival is dependent on two key determinants, both relevant to the situation of the mother. Biological marker of maternal birth weight that is also dependent on the pool of matriarchal birth weights for generations. This in effect defines the genetic pool reserve as well as the weight and gestation of the pregnancy at birth.

The second critical issue is environmental and behavioral and that is the educational status of the mother. This education could be cultural, environmental and empirical as it relates to the survival of the child.

This in effect means a well adjusted and educated mother will ensure the survival of her offspring by either ensuring her own socio-economic and cultural environment by either producing the appropriate environments or by organizing the environment around her for the child to succeed and survive.

Where cultural or empirical IQ will really matters is on the social and economic paradigm more than the biological environment.

That is why it is commonly said that: “If you educate a man, you educate one person; but if you educate a woman, you educate a family, the home, the community and the nation at large. If you educate both then hey can educate the world!

It is clear that a child born in Africa has more opportunities for challenging immunological experiences than a child born in Europe or North America. Talk to Madonna who is not a scientist but has definitely a much higher IQ than your author about the chances of the survival of her newly adopted Malawian son.

The African environment is hostile as it is very conducive to the survival of micro-organisms that are pathogenic to humans than it is in the temperate climate. We now know in current medical research almost all diseases are associated with the competence of our immune system' s ability to differentiate between self and non self.

Infections manifest themselves in many forms and most of the Cardiovascular and chronic diseases including cancers are closely associated with our body's response to viral and other microbial infections.

This is true of Cancer of the Stomach, Peptic Acid Disease, Cardio-vascular accidents and even degenerative disorders. Science is giving us the opportunity to identify the inter-relatedness of most chronic conditions and our immune system's competency.

Our immune system is challenged by more infectious conditions in Developing and temperate climates that makes us all susceptible for continuous challenges to our immune system's response to infections and stressors in life.

In short, it is the biological and physical environment that is more critical than the IQ as suggested by your author. After all, if the Massai in Africa were to define IQ in the sense of their ability to survive in the wilds of Africa, most so called geniuses of the West and noble laureates will not last for long.

So, does that mean the noble scientists have a diminishing Massai defined IQ and as such will have a short survival and quality of life in the Massai world?

Surely, this is a highly erroneous and rather racist research and you should allow alternative perspectives to be explored before you sensationalize such highly controversial research findings.

Remember! Health is not the mere absence of disease, disability and injury, but, the comprehensive wellbeing of the spiritual, emotional, psychological and physical wellbeing of an individual and the community at large. Within this larger construct, the IQ has little to do with health as much as the environment and how our system adopts to it.

All the same, I believe all human beings given the opportunity have the capacity to adopt to new skills, new challenges and opportunities, may be some faster than others but with diverse context and depth and competency.

The question is not IQ, it is rather the hostile environment at home, school, work and leisure that stresses our immune system to such an extent that our whole system collapses in the end. Even geriatric changes are now been associated to our immune system's capacity to adjust with changing age, gender, emotional and physical stressful life events we all face in our life time.

This is not yet complete science and we need to observe and expand research to understand our own body and how we adopt to changing life events.

I request your department which I believe is an Economics center to look at how education and IQ impacts wealth creation rather than delving in highly unscientific association of IQ and health.

It is the environment stupid, more than the IQ that determines our health outcome!

Having said that, nurture or nature is part of the same universe, why bother!

I trust you will consider this contribution as you make future research and line of enquiry to follow us the recent publication in your department.

Please do not hesitate to contact me if I can be helpful. Thanking you for your attention to this matter, I remain;

IQ tests are designed to give approximately this Gaussian distribution. Colors delineate one standard deviation.

An intelligence quotient or IQ is a score derived from a set of standardized tests of intelligence. Intelligence tests come in many forms, and some tests use a single type of item or question. Most tests yield both an overall score and individual subtest scores. Regardless of design, all IQ tests attempt to measure the same general intelligence.[1] Component tests are generally designed and selected because they are found to be predictive of later intellectual development, such as educational achievement.

IQ also correlates with job performance, socioeconomic advancement, and "social pathologies". Recent work has demonstrated links between IQ and health, longevity, and functional literacy. [2] [3] However, IQ tests do not measure all meanings of "intelligence", such as creativity. IQ scores are relative (like placement in a race), not absolute (like the measurement of a ruler).

For people living in the prevailing conditions of the developed world, IQ is highly heritable, and by adulthood the influence of family environment on IQ is undetectable. That is, significant variation in IQ between adults can be attributed to genetic variation, with the remaining variation attributable to environmental sources that are not shared within families. In the United States, marked variation in IQ occurs within families, with siblings differing on average by almost one standard deviation.

The average IQ scores for many populations were rising during the 20th century: a phenomenon called the Flynn effect. It is not known whether these changes in scores reflect real changes in intellectual abilities. On average, IQ scores are stable over a person's lifetime, but some individuals undergo large changes. For example, scores can be affected by the presence of learning disabilities.

Originally, IQ was calculated with the formula A 10-year-old who scored as high as the average 13-year-old, for example, would have an IQ of 130 (100*13/10).

Because this formula only worked for children, it was replaced by a projection of the measured rank on the Gaussian bell curve with a center value (average IQ) of 100, and a standard deviation of 15 or occasionally 16.

[edit] Components of intelligence

Component tests are generally designed and selected because they are found to be predictive of later intellectual development, such as educational achievement. IQ also correlates with job performance, socioeconomic advancement, and, usually negatively, with "social pathologies".

Recent work has demonstrated links between IQ and health, longevity, and functional literacy. [4] [5] However, IQ tests do not measure all meanings of "intelligence", such as creativity. IQ scores are relative (like placement in a race), not absolute (like the measurement of a ruler).

For people living in the prevailing conditions of the developed world, IQ is highly heritable, and by adulthood the influence of family environment on IQ is undetectable. That is, significant variation in IQ between adults can be attributed to genetic variation, with the remaining variation attributable to environmental sources that are not shared within families. In the United States, marked variation in IQ occurs within families, with siblings differing on average by almost one standard deviation.

The average IQ scores for many populations were rising during the 20th century: a phenomenon called the Flynn effect. It is not known whether these changes in scores reflect real changes in intellectual abilities. On average, IQ scores are stable over a person's lifetime, but some individuals undergo large changes. For example, scores can be affected by the presence of learning disabilities.

[edit] HistoryIn 1905, the French psychologist Alfred Binet published the first modern intelligence test, the Binet-Simon intelligence scale.

His principal goal was to identify students who needed special help in coping with the school curriculum. Along with his collaborator Theodore Simon, Binet published revisions of his intelligence scale in 1908 and 1911, the last appearing just before his untimely death. In 1912, the abbreviation of "intelligence quotient" or I.Q., a translation of the German Intelligenz-Quotient, was coined by the German psychologist William Stern.

A further refinement of the Binet-Simon scale was published in 1916 by Lewis M. Terman, from Stanford University, who incorporated Stern's proposal that an individual's intelligence level be measured as an intelligence quotient (I.Q.). Terman's test, which he named the Stanford-Binet Intelligence Scale formed the basis for one of the modern intelligence tests still commonly used today. They are all colloquially known as IQ tests.

[edit] IQ and general intelligence factor

Main article: General intelligence factor

Modern IQ tests produce scores for different areas (e.g., language fluency, three-dimensional thinking, etc.), with the summary score calculated from subtest scores. The average score, according to the bell curve, is 100. Individual subtest scores tend to correlate with one another, even when seemingly disparate in content.

Analysis of individuals' scores on the subtests of a single IQ test or the scores from a variety of different IQ tests (e.g., Stanford-Binet, WISC-R, Raven's Progressive Matrices, Cattell Culture Fair III, Universal Nonverbal Intelligence Test, and others) reveal that they all measure a single common factor and various factors that are specific to each test. This kind of factor analysis has led to the theory that underlying these disparate cognitive tasks is a single factor, termed the general intelligence factor (or g), that corresponds with the common-sense concept of intelligence. In the normal population, g and IQ are roughly 90% correlated and are often used interchangeably.

Various IQ tests measure a standard deviation with different number of points. Thus, when an IQ score is stated, the standard deviation used should also be stated. A result of 124 in a test with a 24-point standard deviation corresponds to a score of 115 in a test with a 15-point deviation. [6]

Where an individual has scores that do not correlate with each other, there is a good reason to look for a learning disability or other cause for the lack of correlation. Tests have been chosen for inclusion because they display the ability to use this method to predict later difficulties in learning.

[edit] Genetics versus environment

Main article: Inheritance of intelligence

The role of genes and environment (nature vs. nurture) in determining IQ is reviewed in Plomin et al. (2001, 2003). The degree to which genetic variation contributes to observed variation in a trait is measured by a statistic called heritability.

Heritability scores range from 0 to 1, and can be interpreted as the percentage of variation (e.g. in IQ) that is due to variation in genes. Twins studies and adoption studies are commonly used to determine the heritability of a trait. Until recently heritability was mostly studied in children. Some studies find the heritability of IQ around 0.5 but the studies show ranges from 0.4 to 0.8;[7] that is, depending on the study, a little less than half to substantially more than half of the variation in IQ among the children studied was due to variation in their genes. The remainder was thus due to environmental variation and measurement error.

A heritability in the range of 0.4 to 0.8 implies that IQ is "substantially" heritable. Studies with adults show that they have a higher heritability of IQ than children do and that heritability could be as high as 0.8.

The American Psychological Association's 1995 task force on "Intelligence: Knowns and Unknowns" concluded that within the white population the heritability of IQ is "around .75" (p. 85). [8] The Minnesota Study of Twins Reared Apart, a multiyear study of 100 sets of reared apart twins which was started in 1979, concluded that about 70% of the variance in IQ was found to be associated with genetic variation. [9]

The heritability of IQ has been tested on large numbers of twins, siblings, parent-child relationships, and adoptees. Evidence from family studies provides the main supporting evidence from which arguments about the relative roles of genetics and environment are constructed. Put all these studies together, which include the IQ tests of tens of thousands of individuals, and the table looks like this[citation needed]:

Percent Correlation of IQ TestsRelationship CorrelationThe same person tested twice 87%Identical twins reared together 86%Identical twins reared apart 76%Fraternal twins reared together 55%Biological siblings 47%Parents and children living together 40%Parents and children living apart 31%Adopted children living together 0%Unrelated people living apart 0%

[edit] Environment

Environmental factors play a major role in determining IQ in extreme situations. Proper childhood nutrition appears critical for cognitive development; malnutrition can lower IQ. Other research indicates environmental factors such as prenatal exposure to toxins, duration of breastfeeding [citation needed], and micronutrient deficiency can affect IQ. In the developed world, there are some family effects on the IQ of children, accounting for up to a quarter of the variance. However, by adulthood, this correlation disappears, so that the IQ of adults living in the prevailing conditions of the developed world may be more heritable.

Nearly all personality traits show that, contrary to expectations, environmental effects actually cause adoptive siblings raised in the same family to be as different as children raised in different families (Harris, 1998; Plomin & Daniels, 1987). Put another way, shared environmental variation for personality is zero, and all environmental effects would be nonshared.

Conversely, IQ is actually an exception to this, at least among children. The IQs of adoptive siblings, who share no genetic relation but do share a common family environment, are correlated at .32. Despite attempts to isolate them, the factors that cause adoptive siblings to be similar have not been identified. However, as explained below, shared family effects on IQ disappear after adolescence.

Active genotype-environment correlation, also called the "nature of nurture", is observed for IQ. This phenomenon is measured similarly to heritability; but instead of measuring variation in IQ due to genes, variation in environment due to genes is determined. One study found that 40% of variation in measures of home environment are accounted for by genetic variation. This suggests that the way human beings craft their environment is due in part to genetic influences.

A study of French children adopted between the ages of 4 and 6 shows the continuing interplay of nature and nurture. The children came from poor backgrounds with I.Q.’s that initially averaged 77, putting them near retardation. Nine years later after adoption, they retook the I.Q. tests, and all of them did better. The amount they improved was directly related to the adopting family’s status. "Children adopted by farmers and laborers had average I.Q. scores of 85.5; those placed with middle-class families had average scores of 92.

The average I.Q. scores of youngsters placed in well-to-do homes climbed more than 20 points, to 98." [10] This study suggests that IQ is not stable over the course of ones lifetime and that, even in later childhood, a change in environment can have a significant effect on IQ.

It is well known that it is possible to increase ones IQ score by training, for example by regulary playing puzzle games. Recent studies have shown that training ones working memory may increase IQ. (Klingberg et al., 2002)

[edit] Development

It is reasonable to expect that genetic influences on traits like IQ should become less important as one gains experiences with age. Surprisingly, the opposite occurs. Heritability measures in infancy are as low as 20%, around 40% in middle childhood, and as high as 80% in adulthood.[11]

Shared family effects also seem to disappear by adulthood. Adoption studies show that, after adolescence, adopted siblings are no more similar in IQ than strangers (IQ correlation near zero), while full siblings show an IQ correlation of 0.6. Twin studies reinforce this pattern: monozygotic (identical) twins raised separately are highly similar in IQ (0.86), more so than dizygotic (fraternal) twins raised together (0.6) and much more than adopted siblings (~0.0).[12]

Most of the IQ studies described above were conducted in developed countries, such as the United States, Japan, and Western Europe. Also, a few studies have been conducted in Moscow, East Germany, and India, and those studies have produced similar results.

Any such investigation is limited to describing the genetic and environmental variation found within the populations studied. This is a caveat of any heritability study.[citation needed]. Another caveat is that people with chromosomal abnormalities - such as klinefelter's syndrome and Triple X syndrome, will score considerably higher than the normal population without the chromosomal abnormalities, when scored against visual IQ tests, not IQ tests that have been tailored to measure IQ against the normal population.[13]

[edit] Mental retardation

About 75–80 percent of mental retardation is familial (runs in the family), and 20–25 percent is due to biological problems, such as chromosomal abnormalities or brain damage. [14] Mild to severe mental retardation is a symptom of several hundred single-gene disorders and many chromosomal abnormalities, including small deletions. Based on twin studies, moderate to severe mental retardation does not appear to be familial, but mild mental retardation does. That is, the relatives of the moderate to severely mentally retarded have normal ranges of IQs, whereas the families of the mildly mentally retarded have lower IQs.

The rate of mental retardation is higher among males than females, according to a 1991 U.S. Centers for Disease Control and Prevention (CDC) study. [15] This is aggravated by the fact that males, unlike females, do not have a spare X chromosome to offset chromosomal defects.

Individuals with IQs below 70 have been essentially exempted from the death penalty in the U.S. since 2002. [16]

[edit] IQ, education, and income

Tambs et al. (1989) found that occupational status, educational attainment, and IQ are individually heritable; and further found that "genetic variance influencing educational attainment … contributed approximately one-fourth of the genetic variance for occupational status and nearly half the genetic variance for IQ". In a sample of U.S. siblings, Rowe et al. (1997) report that the inequality in education and income was predominantly due to genes, with shared environmental factors playing a subordinate role.

[edit] Regression

The heritability of IQ measures the extent to which the IQ of children appears to be influenced by the IQ of parents. Because the heritability of IQ is less than 100%, the IQ of children tends to "regress" towards the mean IQ of the population. That is, high IQ parents tend to have children who are less bright than their parents, whereas low IQ parents tend to have children who are brighter than their parents. The effect can be quantified by the equation where

• is the predicted average IQ of the children; • is the mean IQ of the population to which the parents belong; • h2 is the heritability of IQ;

• m and f are the IQs of the mother and father, respectively. [17]Thus, if the heritability of IQ is 50%, a couple averaging an IQ of 120 may have children that average around an IQ of 110, assuming that both parents come from a population with a median IQ of 100.

A caveat to this reasoning are those children who have chromosomal abnormalities, such as Klinefelter's syndrome and Triple X syndrome whose "normal" IQ is only one indicator; their visual IQ is another indicator. And so forth.[edit] IQ and the brain

Main article: Neuroscience and intelligence[edit] Brain size and IQ

Modern studies using MRI imaging have shown that brain size correlates with IQ (r = 0.35) among adults (McDaniel, 2005). The correlation between brain size and IQ seems to hold for comparisons between and within families (Gignac et al. 2003; Jensen 1994; Jensen & Johnson 1994). However, one study found no familial correlation (Schoenemann et al. 2000).

A study on twins (Thompson et al., 2001) showed that frontal gray matter volume was correlated with g and highly heritable. A related study has reported that the correlation between brain size (reported to have a heritability of 0.85) and g is 0.4, and that correlation is mediated entirely by genetic factors (Posthuma et al 2002).

In a study of the head growth of 633 term-born children from the Avon Longitudinal Study of Parents and Children cohort, it was shown that prenatal growth and growth during infancy were associated with subsequent IQ. The study’s conclusion was that the brain volume a child achieves by the age of 1 year helps determine later intelligence. Growth in brain volume after infancy may not compensate for poorer earlier growth. [18]

[edit] Brain areas associated with IQ

Many different sources of information have converged on the view that the frontal lobes are critical for fluid intelligence. Patients with damage to the frontal lobe are impaired on fluid intelligence tests (Duncan et al 1995). The volume of frontal grey (Thompson et al 2001) and white matter (Schoenemann et al 2005) have also been associated with general intelligence.

In addition, recent neuroimaging studies have limited this association to the lateral prefrontal cortex. Duncan and colleagues (2000) showed using Positron Emission Tomography that problem-solving tasks that correlated more highly with IQ also activate the lateral prefrontal cortex. More recently, Gray and colleagues (2003) used functional magnetic resonance imaging (fMRI) to show that those individuals that were more adept at resisting distraction on a demanding working memory task had both a higher IQ and increased prefrontal activity. For an extensive review of this topic, see Gray and Thompson (2004). [19]

In 2004, Richard Haier, professor of psychology in the Department of Pediatrics and colleagues at University of California, Irvine and the University of New Mexico used MRI to obtain structural images of the brain in 47 normal adults who also took standard IQ tests. The study demonstrated that general human intelligence appears to be based on the volume and location of gray matter tissue in the brain. Regional distribution of gray matter in humans is highly heritable. The study also demonstrated that, of the brain's gray matter, only about 6 percent appeared to be related to IQ. [20]

[edit] Brain structure and IQ

A study involving 307 children (age between six to nineteen) measuring the size of brain structures using magnetic resonance imaging (MRI) and measuring verbal and non-verbal abilities has been conducted (Shaw et al 2006). The study has indicated that there is a relationship between IQ and the structure of the cortex—the characteristic change being the group with the superior IQ scores starts with thinner cortex in the early age then becomes thicker than average by the late teens. [21]

[edit] The Flynn effect

Main article: Flynn effect

The Flynn effect is named after James R. Flynn, a New Zealand based political scientist. He discovered that IQ scores worldwide appear to be slowly rising at a rate of around three IQ points per decade (Flynn, 1999). Attempted explanations have included improved nutrition, a trend towards smaller families, better education, greater environmental complexity, and heterosis (Mingroni, 2004). However, tests are renormalized occasionally to obtain mean scores of 100, for example WISC-R (1974), WISC-III (1991) and WISC-IV (2003). Hence it is difficult to compare IQ scores measured years apart.

There is recent evidence that the tendency for intelligence scores to rise has ended in some first world countries. In 2004, Jon Martin Sundet of the University of Oslo and colleagues published an article documenting scores on intelligence tests given to Norwegian conscripts between the 1950s and 2002, showing that the increase in scores of general intelligence stopped after the mid-1990s and in numerical reasoning subtests, declined. [22]

Thomas W. Teasdale of the University of Copenhagen and David R. Owen of Brooklyn College, City University of New York, discovered similar results in Denmark, where intelligence test results showed no rise across the 1990s. [23]Indications that scores on intelligence tests are not universally climbing have also come from the United Kingdom. Michael Shayer, a psychologist at King's College, University of London, and two colleagues report that performance on tests of physical reasoning given to children entering British secondary schools declined markedly between 1976 and 2003. [24]

[edit] Group differences

Among the most controversial issues related to the study of intelligence is the observation that intelligence measures such as IQ scores vary between populations. While there is little scholarly debate about the existence of some of these differences, the reasons remain highly controversial both within academia and in the public sphere.

[edit] Sex and intelligence

Main article: Sex and intelligence

Most studies show that despite sometimes significant differences in subtest scores, men and women have the same average IQ. Women perform better on tests of memory and verbal proficiency for example, while men perform better on tests of mathematical and spatial ability. Although gender-related differences in average IQ are insignificant, male scores display a higher variance: there are more men than women with both very high and very low IQs (for more details, see main article Sex and intelligence).

[edit] Race and IQ

Main article: Race and intelligence

While IQ scores of individual members of different racial or ethnic groups are distributed across the IQ scale, groups may vary in where their members cluster along the IQ scale. East Asians cluster higher than Europeans, while Hispanics and Sub-Saharan Africans cluster lower in the USA.[25] Much research has been devoted to the extent and potential causes of racial-ethnic group differences in IQ, and the underlying purposes and validity of the tests has been examined. Most experts conclude that examination of many types of test bias and simple differences in socioeconomic status have failed to explain the IQ clustering differences. [26] For a summary of expert opinions, see Race and Intelligence.

The findings in this field are often thought to conflict with fundamental social philosophies, and have resulted in controversy.[27]

[edit] Health and IQ

Persons with a higher IQ have generally lower adult morbidity and mortality. This may be because they better avoid injury and take better care of their own health, or alternatively may be due to a slight increased propensity for material wealth (see above). Post-Traumatic Stress Disorder, severe depression, and schizophrenia are less prevalent in higher IQ bands.

The Archive of General Psychiatry published a longitudinal study of a randomly selected sample of 713 study participants (336 boys and 377 girls), from both urban and suburban settings. Of that group, nearly 76 percent had suffered through at least one traumatic event. Those participants were assessed at age 6 years and followed up to age 17 years.

In that group of children, those with an IQ above 115 were significantly less likely to have Post-Traumatic Stress Disorder as a result of the trauma, less likely to display behavioral problems, and less likely to experience a trauma. The low incidence of Post-Traumatic Stress Disorder among children with higher IQs was true even if the child grew up in an urban environment (where trauma averaged three times the rate of the suburb), or had behavioral problems. [28] On the other hand, higher IQ shows a higher prevalence of those conditioned with Obsessive Compulsive Disorder. [29]

Research in Scotland has shown that a 15-point lower IQ meant people had a fifth less chance of seeing their 76th birthday, while those with a 30-point disadvantage were 37% less likely than those with a higher IQ to live that long. [30]A decrease in IQ has also been shown as an early predictor of late-onset Alzheimer's Disease and other forms of dementia. In a 2004 study, Cervilla and colleagues showed that tests of cognitive ability provide useful predictive information up to a decade before the onset of dementia.[31]

However, when diagnosing individuals with a higher level of cognitive ability, in this study those with IQ's of 120 or more, [32] patients should not be diagnosed from the standard norm but from an adjusted high-IQ norm that measured changes against the individual's higher ability level.

In 2000, Whalley and colleagues published a paper in the journal Neurology, which examined links between childhood mental ability and late-onset dementia. The study showed that mental ability scores were significantly lower in children who eventually developed late-onset dementia when compared with other children tested. [33]

The longstanding belief that breast feeding correlates with an increase in the IQ of offspring has been challenged in a 2006 paper published in the British Medical Journal. The study used data from 5,475 children, the offspring of 3,161 mothers, in a longitudinal survey.

The results indicated that mother's IQ, not breast feeding, explained the differences in the IQ scores of offspring. The results of this study indicated that prior studies had not allowed for the mother's IQ. Since mother's IQ was predictive of whether a child was breast fed, the study concluded that "breast feeding [itself] has little or no effect on intelligence in children." Instead, it was the mother's IQ that had a significant correlation with the IQ of her offspring, whether the offspring was breast fed or was not breast fed. [34][edit] Wealth and IQ

A book IQ and the Wealth of Nations, claims to show that the wealth of a nation can in large part be explained by the average IQ score. This claim has been both disputed and supported in peer-reviewed papers. The data used has also been questioned.

In addition, IQ and its correlates to health, violent crime, gross state product, and government effectiveness are the subject of a 2006 paper in the publication Intelligence. The paper breaks down IQ averages by U.S. states using the federal government's National Assessment of Educational Progress math and reading test scores as a source. [35]

[edit] Practical validity

Linear correlations between 1000 pairs of numbers. The data are graphed on the lower left and their correlation coefficients listed on the upper right. Each set of points correlates maximally with itself, as shown on the diagonal (all correlations = +1).Evidence for the practical validity of IQ comes from examining the correlation between IQ scores and life outcomes.Economic and social correlates of IQFactors CorrelationSchool grades and IQ 0.5Total years of education and IQ 0.55IQ and parental socioeconomic status 0.33Job performance and IQ 0.54Negative social outcomes and IQ −0.2IQs of identical twins 0.86IQs of husband and wife 0.4Heights of parent and child 0.47Economic and social correlates of IQ in the USA

Research shows that general intelligence plays an important role in many valued life outcomes. In addition to academic success, IQ correlates with job performance (see below), socioeconomic advancement (e.g., level of education, occupation, and income), and "social pathology" (e.g., adult criminality, poverty, unemployment, dependence on welfare, children outside of marriage). Recent work has demonstrated links between general intelligence and health, longevity, and functional literacy. Correlations between g and life outcomes are pervasive, though IQ and happiness do not correlate. IQ and g correlate highly with school performance and job performance, less so with occupational prestige, moderately with income, and to a small degree with law-abidingness.

General intelligence (in the literature typically called "cognitive ability") is the best predictor of job performance by the standard measure, validity. Validity is the correlation between score (in this case cognitive ability, as measured, typically, by a paper-and-pencil test) and outcome (in this case job performance, as measured by a range of factors including supervisor ratings, promotions, training success, and tenure), and ranges between −1.0 (the score is perfectly wrong in predicting outcome) and 1.0 (the score perfectly predicts the outcome). See validity (psychometric). The validity of cognitive ability for job performance tends to increase with job complexity and varies across different studies, ranging from 0.2 for unskilled jobs to 0.8 for the most complex jobs.

A meta-analysis (Hunter and Hunter, 1984) which pooled validity results across many studies encompassing thousands of workers (32,124 for cognitive ability), reports that the validity of cognitive ability for entry-level jobs is 0.54, larger than any other measure including job tryout (0.44), experience (0.18), interview (0.14), age (−0.01), education (0.10), and biographical inventory (0.37).

Because higher test validity allows more accurate prediction of job performance, companies have a strong incentive to use cognitive ability tests to select and promote employees. IQ thus has high practical validity in economic terms.

The utility of using one measure over another is proportional to the difference in their validities, all else equal. This is one economic reason why companies use job interviews (validity 0.14) rather than randomly selecting employees (validity 0.0).However, legal barriers, most prominently the U.S. Civil Rights Act, as interpreted in the 1971 United States Supreme Court decision Griggs v. Duke Power Co., have prevented American employers from using cognitive ability tests as a controlling factor in selecting employees where (1) the use of the test would have a disparate impact on hiring by race and (2) where the test is not shown to be directly relevant to the job or class of jobs at issue.

Instead, where there is not direct relevance to the job or class of jobs at issue, tests have only been legally permitted to be used in conjunction with a subjective appraisal process. The U.S. military uses the Armed Forces Qualifying Test (AFQT), as higher scores correlate with significant increases in effectiveness of both individual soldiers and units, [36] and Microsoft is known for using non-illegal tests that correlate with IQ tests as part of the interview process, weighing the results even more than experience in many cases. [37]

Some researchers have echoed the popular claim that "in economic terms it appears that the IQ score measures something with decreasing marginal value. It is important to have enough of it, but having lots and lots does not buy you that much." [38] [39]However, some studies suggest IQ continues to confer significant benefits even at very high levels. [40] Ability and performance for jobs are linearly related, such that at all IQ levels, an increase in IQ translates into a concomitant increase in performance (Coward and Sackett, 1990). In an analysis of hundreds of siblings, it was found that IQ has a substantial effect on income independently of family background (Murray, 1998).

Other studies question the real-world importance of whatever is measured with IQ tests, especially for differences in accumulated wealth and general economic inequality in a nation. IQ correlates highly with school performance but the correlations decrease the closer one gets to real-world outcomes, like with job performance, and still lower with income. It explains less than one sixth of the income variance. [41] Even for school grades, other factors explain most the variance. One study found that, controlling for IQ across the entire population, 90 to 95 percent of economic inequality would continue to exist. [42]

Another recent study (2002) found that wealth, race, and schooling are important to the inheritance of economic status, but IQ is not a major contributor and the genetic transmission of IQ is even less important. [43] Some argue that IQ scores are used as an excuse for not trying to reduce poverty or otherwise improve living standards for all. Claimed low intelligence has historically been used to justify the feudal system and unequal treatment of women (but note that many studies find identical average IQs among men and women; see sex and intelligence). In contrast, others claim that the refusal of "high-IQ elites" to take IQ seriously as a cause of inequality is itself immoral. [44]

[edit] Public policy

Main article: Intelligence and public policy

Because public policy is often intended to influence the same outcomes (for example to improve education, fight poverty and crime, promote fairness in employment, and counter racial discrimination), policy decisions frequently interact with intelligence measures. In some cases, modern public policy references intelligence measures or even aims to alter cognitive development directly.

While broad consensus exists that intelligence measures neither dictate nor preclude any particular social policy, controversy surrounds many other aspects of this interaction. Central issues concern whether intelligence measures should be considered in policy decisions, the role of policy in influencing or accounting for group differences in measured intelligence, and the success of policies in light of individual and group intelligence differences. The importance and sensitivity of the policies at issue have produced an often-emotional ongoing debate spanning scholarly inquiry and the popular media from the national to the local level.

[edit] Use of IQ in the United States legal system

Title VII of the Civil Rights Act generally prohibits employment practices that are unfair or discriminatory. One provision of Title VII, codified at 42 USC 2000e-2(h), specifically provides that it is not an "unlawful employment practice for an employer to give and to act upon the results of any professionally developed ability test provided that such test, its administration or action upon the results is not designed, intended or used to discriminate because of race, color, religion, sex or national origin." This statute was interpreted by the Supreme Court in Griggs v. Duke Power Co., 401 US 424 (1971).

In Griggs, the Court ruled that the reliance solely on a general IQ test that was not found to be specifically relevant to the job at issue was a discriminatory practice where it had a "disparate impact" on hiring. The Court gave considerable weight in its ruling to an Equal Employment Opportunity Commission regulation interpreting Section 2002e-2(h)'s reference to a "professionally developed ability test" to mean "a test which fairly measures the knowledge or skills required by the particular job or class of jobs which the applicant seeks, or which fairly affords the employer a chance to measure the applicant's ability to perform a particular job or class of jobs." In other words, the use of any particular test would need to be shown to be relevant to the particular job or class of jobs at issue.

In the educational context, the 9th Circuit Court of Appeals interpreted similar state and federal statutes to require that IQ Tests not be used in a manner that was determinative of tracking students into classes designed for the mentally retarded. Larry P. v. Riles, 793 F.2d 969 (9th Cir. 1984).

The court specifically found that the tests involved were designed and standardized based on an all-white population, and had not undergone a legislatively mandated validation process. In addition, the court ruled that predictive validity for a general population is not sufficient, since the rights of an individual student were at issue, and emphasized that had the tests not been treated as controlling but instead used as part of a thorough and individualized assessment by a school psychologist a different result would have been obtained.

In September 1982, the judge in the Larry P. case, Federal District Judge Robert F. Peckham, relented in part in response to a lawsuit brought by black parents who wanted their children tested. The parents' attorney, Mark Bredemeier, said his clients viewed the modern special education offered by California schools today as helpful to children with learning disabilities, not a dead-end track, as parents contended in the original 1979 Larry P. case.

The Supreme Court of the United States has utilized IQ test results during the sentencing phase of some criminal proceedings. The Supreme Court case of Atkins v. Virginia, decided June 20, 2002, [45] held that executions of mentally retarded criminals are "cruel and unusual punishments" prohibited by the Eighth Amendment. In Atkins the court stated that

"…[I]t appears that even among those States that regularly execute offenders and that have no prohibition with regard to the mentally retarded, only five have executed offenders possessing a known IQ less than 70 since we decided Penry. The practice, therefore, has become truly unusual, and it is fair to say that a national consensus has developed against it."

In overturning the Virginia Supreme Court's holding, the Atkins opinion stated that petitioner's IQ result of 59 was a factor making the imposition of capital punishment a violation of his eighth amendment rights. In the opinion's notes the court provided some of the facts relied upon when reaching their decision

At the sentencing phase, Dr. Nelson testified: "Atkins' full scale IQ is 59. Compared to the population at large, that means less than one percentile…. Mental retardation is a relatively rare thing. It's about one percent of the population." App. 274. According to Dr. Nelson, Atkins' IQ score "would automatically qualify for Social Security disability income." Id., at 280. Dr. Nelson also indicated that of the over 40 capital defendants that he had evaluated, Atkins was only the second individual who met the criteria for mental retardation. Id., at 310. He testified that, in his opinion, Atkins' limited intellect had been a consistent feature throughout his life, and that his IQ score of 59 is not an "aberration, malingered result, or invalid test score." Id., at 308.

.The Social Security Administration also uses IQ results when deciding disability claims. In certain cases, IQ results alone are used (in those cases where the result shows a "full scale IQ of 59 or less") and in other cases IQ results are used along with other factors (for a "full scale IQ of 60 through 70") when deciding whether a claimant qualifies for Social Security Disability benefits.[46]In addition, because people with IQs below 80 (the 10th percentile, Department of Defense "Category V") are difficult to train, federal law bars their induction into the military. As of 2005, only 4 percent of the recruits were allowed to score as low as in the 16th to 30th percentile, a grouping known as "Category IV" on the U.S. Armed Forces' mental-aptitude exam. [47][edit] Validity and g-loading of specific testsWhile IQ is sometimes treated as an end unto itself, scholarly work on IQ focuses to a large extent on IQ's validity, that is, the degree to which IQ predicts outcomes such as job performance, social pathologies, or academic achievement. Different IQ tests differ in their validity for various outcomes.Tests also differ in their g-loading, which is the degree to which the test score reflects general mental ability rather than a specific skill or "group factor" such as verbal ability, spatial visualization, or mathematical reasoning). g-loading and validity have been observed to be related in the sense that most IQ tests derive their validity mostly or entirely from the degree to which they measure g (Jensen 1998).[edit] Controversy[edit] Social constructThis section does not cite its references or sources.You can help Wikipedia by introducing appropriate citations.Some maintain that IQ is a social construct invented by the privileged classes [citation needed], used to maintain their privilege.[citation needed] Others maintain that intelligence, measured by IQ or g, reflects a real ability, is a useful tool in performing life tasks and has a biological reality.The social-construct and real-ability interpretations for IQ differences can be distinguished because they make opposite predictions about what would happen if people were given equal opportunities. The social explanation predicts that equal treatment will eliminate differences, while the real-ability explanation predicts that equal treatment will accentuate differences. Evidence for both outcomes exists. Achievement gaps persist in socioeconomically advantaged, integrated, liberal, suburban school districts in the United States (see Noguera, 2001). Test-score gaps tend to be larger at higher socioeconomic levels (Gottfredson, 2003). Some studies have reported a narrowing of score gaps over time.The reduction of intelligence to a single score seems extreme and unrealistic to many people. Opponents argue that it is much more useful to know a person's strengths and weaknesses than to know a person's IQ score. Such opponents often cite the example of two people with the same overall IQ score but very different ability profiles.[citation needed] As measured by IQ tests, most people have highly balanced ability profiles, with differences in subscores being greater among the more intelligent.[citation needed] However, this assumes the ability of IQ tests to comprehensively gauge the wide variety of human intellectual abilities.There are different types of IQ tests. Certainly the information described on this topic relates to a generic IQ test—against a general population, and therefore the results obtained are consistent across the population. However the results do not tell a full story, and are slanted towards 46,XX, and 46,XY candidates.[citation needed]Candidates with Klinefelter's Syndrome, have a decreased frontal lobe, so for the most part have a reduced IQ when measured against the normal population (46,XX, and 46,XY candidates), but have an enhanced parietal lobe. If measured against IQ tests that are based on matching (patterns, shapes, colors, mathematical series, puzzles), some klinefelters measure into the genius level.[citation needed]The creators of IQ testing did not intend for the tests to gauge a person's worth, and in many (or in all) situations, IQ may have little relevance. [citation needed][edit] The Mismeasure of ManSome scientists dispute psychometrics entirely. In The Mismeasure of Man, a controversial book, professor Stephen Jay Gould argued that intelligence tests were based on faulty assumptions and showed their history of being used as the basis for scientific racism. He wrote:…the abstraction of intelligence as a single entity, its location within the brain, its quantification as one number for each individual, and the use of these numbers to rank people in a single series of worthiness, invariably to find that oppressed and disadvantaged groups—races, classes, or sexes—are innately inferior and deserve their status. (pp. 24–25) He spent much of the book criticizing the concept of IQ, including a historical discussion of how the IQ tests were created and a technical discussion of why g is simply a mathematical artifact. Later editions of the book included criticism of The Bell Curve, also a controversial book. Despite the many updates Gould made to his book, he did not discuss the modern usage of Magnetic Resonance Imaging (MRI) and other modern brain imaging techniques used in psychometrics.Arthur Jensen, Professor of Educational Psychology, University of California, Berkeley, responded to Gould's criticisms in a paper titled The Debunking of Scientific Fossils and Straw Persons. [48]

[edit] The view of the American Psychological AssociationIn response to the controversy surrounding The Bell Curve, the American Psychological Association's Board of Scientific Affairs established a task force to write a consensus statement on the state of intelligence research which could be used by all sides as a basis for discussion. The full text of the report is available at a third-party website. [49]The findings of the task force state that IQ scores do have high predictive validity for individual differences in school achievement. They confirm the predictive validity of IQ for adult occupational status, even when variables such as education and family background have been statistically controlled. They agree that individual (but specifically not population) differences in intelligence are substantially influenced by genetics.They state there is little evidence to show that childhood diet influences intelligence except in cases of severe malnutrition. They agree that there are no significant differences between the average IQ scores of males and females. The task force agrees that large differences do exist between the average IQ scores of blacks and whites, and that these differences cannot be attributed to biases in test construction. While they admit there is no empirical evidence supporting it, the APA task force suggests that explanations based on social status and cultural differences may be possible. Regarding genetic causes, they noted that there is not much direct evidence on this point, but what little there is fails to support the genetic hypothesis.The APA journal that published the statement, American Psychologist, subsequently published eleven critical responses in January 1997, most arguing that the report failed to examine adequately the evidence for partly-genetic explanations.The report was published in 1995 and thus does not include a decade of recent research.[edit] IQ testThis section does not cite its references or sources.You can help Wikipedia by introducing appropriate citations.The controversy over IQ tests (also called cognitive ability tests [citation needed]), what they measure, and what this means for society has not abated since their initial development by Alfred Binet.IQ tests rely largely upon Symbolic Logic [citation needed] as a means to scoring, and as Symbolic Logic is not inherently synonymous with intelligence [citation needed], the question remains as to exactly what is being measured via such tests. For instance, it is feasible that someone could possess a prodigious wealth of emotional intelligence while being simultaneously unable to comprehend the significance of sequentially arranged shapes [citation needed]. Additionally, someone who cannot read would be at a significant disadvantage on an IQ test [citation needed], though illiteracy is not indicative of being unintelligent. Measurements of other forms of "intelligence" have been proposed to augment the current IQ Testing Methodology, though such alternative measurements may also be a subject of debate.Some key issues in the debate include defining intelligence itself (see general intelligence factor) and the political ramification of findings.Some proponents of IQ testing argue that lower scores by certain groups justify cutting back on welfare and programs like Head Start and New Deal. Many proponents believe different IQ scores demonstrate that power and wealth will always be distributed unequally. Critics claim that IQ tests do not measure intelligence, but rather a specific skill set valued by those who create IQ tests.Various statistical studies have reported that income level, education level, nutrition level, race, and sex all correlate with IQ scores, but what this means is debated.Some researchers have concluded from twin studies and adoption studies that IQ has high heritability, and this is often interpreted by the general public as meaning that there is an immutable genetic factor affecting or determining intelligence [citation needed]. This hereditarian interpretation fuels much of the controversy over books such as The Bell Curve, which claimed that various racial groups have lower or higher group intelligence than other racial and ethnic groups (East Asians and Ashkenazi Jews, according to The Bell Curve, are slightly more intelligent on the average than generic whites, whereas blacks on the average have slightly lower IQs) and suggested changing public policy as a result of these findings.The degree to which nature versus nurture influences the development of human traits (especially intelligence) is one of the most intractable scholarly controversies of modern times.

Denis CampbellSunday November 5, 2006The Observer The London School of Economics is embroiled in a row over academic freedom after one of its lecturers published a paper alleging that African states were poor and suffered chronic ill-health because their populations were less intelligent than people in richer countries.

Satoshi Kanazawa, an evolutionary psychologist, is now accused of reviving the politics of eugenics by publishing the research which concludes that low IQ levels, rather than poverty and disease, are the reason why life expectancy is low and infant mortality high. His paper, published in the British Journal of Health Psychology, compares IQ scores with indicators of ill health in 126 countries and claims that nations at the top of the ill health league also have the lowest intelligence ratings.

Paul Collins, a spokesman for War On Want, the international development charity, said the research 'runs the risk of resurrecting the racist stereotype that Africans are responsible for their own plight, and may reinforce prejudices that Africans are less intelligent'. Collins added: 'The notion that people in poor countries have inferior intelligence has been disproved by much research in the past. This is another example, which other academics will shoot down.'

Philippa Atkinson, who chairs the LSE student union's 85-strong Africa Forum and teaches in the school's Department of Government, said the paper 'reflects the now discredited theories of eugenics, which should have been left behind'.

'Eugenics was a very influential discourse for centuries,' she said. 'It's the discourse that colonialism and racism in America until the Sixties were based on, and was part of the basis of apartheid too. Nobody could prove that there are racial or national differences in IQ. It's very, very controversial to say that national IQ levels are low in Africa, and completely unproven. It's a surprise that the odd person would try to bring it back,' she said.

However, she said the research contained some interesting ideas and merited serious consideration, and stressed that academics such as Kanazawa should not be deterred from exploring controversial subjects.

The reaction to Kanazawa's paper will reopen the simmering debate about whether academics are entitled to express opinions that many people may find offensive. The Observer revealed last March that Frank Ellis, a lecturer in Russian and Slavonic studies at Leeds University, supported the Bell Curve theory, which holds that black people are less intelligent than whites. He also believed that women did not have the same intellectual capacity as men and backed the 'humane' repatriation of ethnic minorities. Initially, the university backed Ellis, despite protests by students and teaching staff, but he took early retirement in July.

Kanazawa declined to comment on either War on Want or Atkinson's allegations about reviving eugenics because, he said, other academics had come up with the national IQ scores that underpinned his analysis of 126 countries. In the paper he cites Ethiopia's national IQ of 63, the world's lowest, and the fact that men and women are only expected to live until their mid-40s as an example of his finding that intelligence is the main determinant of someone's health.

Having examined the effects of economic development and income inequality on health, he was 'surprised' to find that IQ had a much more important impact, he said. 'Poverty, lack of sanitation, clean water, education and healthcare do not increase health and longevity, and nor does economic development.'

The LSE declined to offer any opinion on Kanazawa's conclusions but defended his right to publish controversial research. A spokeswoman said: 'This is academic research by Dr Kanazawa based on empirical data and published in a peer-reviewed journal. People may agree or disagree with his findings and are at liberty to voice their opinions to him. The school does not take any institutional view on the work of individual academics.' Kate Raworth, a senior researcher with Oxfam, said it was 'ridiculous' for Kanazawa to blame ill health on low IQ and 'very irresponsible' to reach such conclusions using questionable and 'fragile' international data on national IQ levels.

Kanazawa's article was a 'misrepresentation' of the true causes of ill health in Kenya, added Shah. 'It portrays a bad picture of Kenya, because not everyone in Kenya has an IQ of 72. If there was more education, Kenyans would be wiser about their health.'

CONFIDENTIALITY NOTICE: This electronic message, including any attachment(s), is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. .

The London School of Economics is embroiled in a row over academic freedom after one of its lecturers published a paper alleging that African states were poor and suffered chronic ill-health because their populations were less intelligent than people in richer countries. Satoshi Kanazawa, an evolutionary psychologist, is now accused of reviving the politics of eugenics by publishing the research which concludes that low IQ levels, rather than poverty and disease, are the reason why life expectancy is low and infant mortality high. His paper, published in the British Journal of Health Psychology, compares IQ scores with indicators of ill health in 126 countries and claims that nations at the top of the ill health league also have the lowest intelligence ratings. In the paper he cites Ethiopia's national IQ of 63 Paul Collins, a spokesman for War On Want, the international development charity, said the research 'runs the risk of resurrecting the racist stereotype that Africans are responsible for their own plight, and may reinforce prejudices that Africans are less intelligent'.

Collins added: 'The notion that people in poor countries have inferior intelligence has been disproved by much research in the past. This is another example, which other academics will shoot down.'

Philippa Atkinson, who chairs the LSE student union's 85-strong Africa Forum and teaches in the school's Department of Government, said the paper 'reflects the now discredited theories of eugenics, which should have been left behind'. 'Eugenics was a very influential discourse for centuries,' she said. 'It's the discourse that colonialism and racism in America until the Sixties were based on, and was part of the basis of apartheid too. Nobody could prove that there are racial or national differences in IQ. It's very, very controversial to say that national IQ levels are low in Africa , and completely unproven. It's a surprise that the odd person would try to bring it back,' she said.

However, she said the research contained some interesting ideas and merited serious consideration, and stressed that academics such as Kanazawa should not be deterred from exploring controversial subjects.

The reaction to Kanazawa 's paper will reopen the simmering debate about whether academics are entitled to express opinions that many people may find offensive. The Observer revealed last March that Frank Ellis, a lecturer in Russian and Slavonic studies at Leeds University , supported the Bell Curve theory, which holds that black people are less intelligent than whites. He also believed that women did not have the same intellectual capacity as men and backed the 'humane' repatriation of ethnic minorities. Initially, the university backed Ellis, despite protests by students and teaching staff, but he took early retirement in July.

Kanazawa declined to comment on either War on Want or Atkinson's allegations about reviving eugenics because, he said, other academics had come up with the national IQ scores that underpinned his analysis of 126 countries. In the paper he cites Ethiopia 's national IQ of 63, the world's lowest, and the fact that men and women are only expected to live until their mid-40s as an example of his finding that intelligence is the main determinant of someone's health.

Having examined the effects of economic development and income inequality on health, he was 'surprised' to find that IQ had a much more important impact, he said. 'Poverty, lack of sanitation, clean water, education and healthcare do not increase health and longevity, and nor does economic development.'

The LSE declined to offer any opinion on Kanazawa 's conclusions but defended his right to publish controversial research. A spokeswoman said: 'This is academic research by Dr Kanazawa based on empirical data and published in a peer-reviewed journal. People may agree or disagree with his findings and are at liberty to voice their opinions to him. The school does not take any institutional view on the work of individual academics.'

Kate Raworth, a senior researcher with Oxfam, said it was 'ridiculous' for Kanazawa to blame ill health on low IQ and 'very irresponsible' to reach such conclusions using questionable and 'fragile' international data on national IQ levels.

Kanazawa 's article was a 'misrepresentation' of the true causes of ill health in Kenya , added Shah. 'It portrays a bad picture of Kenya , because not everyone in Kenya has an IQ of 72. If there was more education, Kenyans would be wiser about their health.' --------------- Contact info for Dr. Satoshi Kanazawas.kanazawa@lse.ac.ukLSE phone number: 020 7955 7297WebSite --------------- Related Links

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in relation to the recent controversy of this guy from LSE. I'd like to proudly bring to your attention a forthcoming review of Dr. Girma Berhanu from Goteborg University for the controversial book "IQ and the Wealth of Nations" by Lynn and Vanhanen from which Kanazawa from LSE copied the alleged national IQ's. As recalled, Lynn and Vanhanen calculated 63 as the national IQ of Ethiopia (the lowest in the world) and it turns out that they did so on the basis of test results from Ethiopian-Jewish young students in Israel (a fact that was brought to my attention by Dr. Girma) which in itself is outrageous!

you can read the abstract for his review and also a letter he sent to the journal's editor.I really thank Dr. Girma Berhanu for taking the initiative to challenge these racist views that unfortunately many find still to be appropriate to entertain in higher educational and academic institutions.

here is what i wrote on Kanazawa's article: http://www.ethrev.com/articles/Nov2006/DanielAlemu_11082006.htmlThanks,Daniel Alemu,London

This paper is a response to the book ”IQ and the wealth of nations” written by Richard Lynn & Tatu Vanhanen. It is a critique of the authors’ major assertion that a significant part of the gap between rich and poor countries is due to differences in national intelligence. (The authors claim that they have evidence that differences in national IQ account for the substantial variation in national per capita income and growth).

This paper debunks their assumptions that intellectual and income differences between nations stems from genetic differences. This critique provides an extended review of the research literature that tells different stories (from what the authors postulate) about the concept of intelligence, what IQ measures and does not measure. The paper exposes the racist, sexist and antihuman nature of the research tradition in which the authors anchored their studies and the deep methodological flaw, and theoretical assumptions used in their book.

The low standards of scholarship evident in the book render it largely irrelevant for modern science. This paper has specifically dealt with the IQ value of Ethiopian immigrants that came from Israel, used by the authors as representing the National Average IQ of Ethiopia. Most of these immigrants hade rudimentary knowledge of literacy, and experienced abrupt transition from rural Ethiopia to Israel with all the accompanying effects that it entails such as trauma, dislocation and cultural shock. The test was conducted a few months after their arrival. That specific study (conducted by two Israelis) that assigns low IQ for the immigrants is also replete with technical/statistical errors to say the least. The paper concludes that this is tantamount to intellectual genocide deserving a legal treatment by the International Court of Justice.Keywords: Scientific racism, Mental (IQ) testing, Intelligence, Economic development, Intellectual Genocide the request for the review of the book:

(1)The book I want to comment on is entitled”IQ and the wealth ofnations”. It is written by Richard Lynn (prof. emeritus of psychology at theUniversity of Ulster, North Ireland) and Tatu Vanhanen (prof. emeritus ofpolitical science at the University of Tampere in Finland). I came tonotice the debate surrounding the book this past summer during my holidayin Finland. The second author, Prof. Vanhanen, was interviewed by a Finnishjournalist (s) about the book and he expressed his view that IQ and thewealth of nations are strongly correlated and the reason why some countriesare poor has to do with their IQ. He further indicated that IQ issubstantially heritable and racial differences in intelligence are not a mythbut a fact of life. His statement also carried the message that poorcountries should blame themselves for their poverty. His outrageousstatements were widely criticized by Finnish media and have been the subjectof hot debate during this past summer.

I presume the issue became interesting not really because the governing elite is genuinely concerned about the cultural / political message that he conveyed but because the man is the father of the current prime minister of Finland. And it was the opposition party that instigated the debate which in many ways embarrassed the prime minister. The prime minister commented “my father is a bit confused because of age”. This is just to tell you how I came to read the book.The authors argue that a significant part of the gap between rich and poorcountries is due to differences in national intelligence. Their hypothesisis that the intelligence of the populations has been a major factor responsiblefor the national differences in economic growth and the gap in per capitaincome between rich and poor nations The argument is line with Arthur R. Jensen’s controversial article in Harvard Educational Review (1969) through to Richard Herrnstein andCharles Murray’s (1994) book, The Bell curve and J. Philippe Ruston’s bookRace, evolution and behavior (?). The difference is that these studiesattempt to document the relationship between IQ and individual achievementand racial differences in intelligence where as Lynn and Vanhanen havescaled this connection up to a national level. The authors ridiculeenrichment programmes and cognitive education aimed at raising schoolperformance among disadvantaged children.

To get to my point, the IQ figure which stood to represent Ethiopia camefrom Israel, not directly from Ethiopia[1]. It is very likely that a few ofthem (I mean ‘the people whose apparent IQ levels were used’) were my friends. Most of these students (250) who are described in Lynn’s and Vanhanen’s book as having IQs of 63 are presently having a satisfying life and are occupationally competent and socially adequate. (Theyare in their late 20s or early 30s.) I am confident that some of them havedone their first (and second) degrees, if not in Israel in the USA. As many ofus know, these young immigrants were new arrivals, malnourished, unfamiliarwith “western school based skills”; they had lived as refugees in the Sudan underhard poverty, while in Ethiopia they lived most of their life in isolationfrom and suffering discrimination from the dominant Christian neighbors, and many lost their parents during the mysterious journey to Israel; they were “saved”through a dramatic life-saving operation by Mossad. Most of these young people had rudimentary knowledge of formal education and the Hebrew language, and had followed a very traditional way of life while in Ethiopia, so the dramatic and abrupt transition from village life in Ethiopia to Israel which occurred en masse was accompanied by adjustment crises which in turn immensely affected their learning and integration in to Israeli society. The authorstested these young people and concluded that the average Ethiopian IQ is 63.What is outrageous about the book is its emphasis on one direction ofcausation ie a high IQ is the cause of a high income and intellectual andincome differences between nations stems from genetic differences. “… webelieve that national differences in intelligence have a substantialgenetic basis…” (p.193 ) Do they have the data to substantiate this claim? None, except for a fragmented, undocumented and extremely over-simplified assertion about the effects of trans-racial adoption and a few twin studies. The distorted data allows them to talk only about the strength of relationships not cause and effect relationships.With kindest regards!Girma Berhanu[1] (see Kaniel, Shlomo; Fisherman, Shraga.Title Level of performance and distribution of errors in the Progressive Matrices test: A comparison of Ethiopian immigrant and native Israeli adolescents.

SourceInternational Journal of Psychology. Vol 26(1) 1991, 25-33

IQ and the Wealth of NationsFrom Wikipedia, the free encyclopediaJump to: navigation, search

IQ and the Wealth of NationsIQ and the Wealth of Nations is a controversial 2002 book by Dr. Richard Lynn, Professor Emeritus of Psychology at the University of Ulster, Northern Ireland, and Dr. Tatu Vanhanen, Professor Emeritus of Political Science at the University of Tampere, Tampere, Finland. The book demonstrates that differences in national income (in the form of per capita gross domestic product) correlate with, and arguably attributes it to, differences in average national IQ.The book was followed by Lynn's 2006 Race Differences in Intelligence, which expands the data by nearly four times and concludes the average human IQ is presently 90 when compared to a norm of 100 based on UK data, or two thirds of a standard deviation below the UK norm.o [edit] Outline

The central thesis of IQ and the Wealth of Nations is that the average IQ of a nation correlates with its GDP. Above is a scatterplot with Lynn and Vanhanen's IQ figures and estimates² (explained below) plotted against 2004 per capita GDP (PPP), as reported by the IMF.³ Similar diagrams appear in the book.The book includes the authors' estimates of average IQ scores for each country, based on their analysis of published reports; their observation that national gross domestic product per capita is correlated with IQ; and their conclusion that the IQ differences correlated with income differences by a factor of about 0.7, meaning that IQ explains more than half of the variation in per capita GDP.The authors stated that they believe IQ is due to both genetic and environmental factors. They also stated that low GDP can cause low IQ, just as low IQ can cause low GDP. (See: Positive feedback)The authors argued that it is the ethical responsibility of rich, high-IQ nations to financially assist poor, low-IQ nations, as it is the responsibility of rich citizens to assist the poor.The book was cited several times in the popular press, notably the British conservative newspaper The Times. Because Tatu Vanhanen is the father of Matti Vanhanen, the Finnish Prime minister, his work has received wide publicity in Finland.[edit] National IQ estimatesCentral to the book's thesis is a tabulation of what Lynn and Vanhanen believe to be the average IQs of the world's nations. Rather than do their own IQ studies (a potentially massive project), the authors average and adjust existing studies.For most of the 185 nations, no reliable studies are available. In those cases, the authors have used an estimated value by taking averages of the IQs of surrounding nations. For example, the authors arrived at a figure of 84 for El Salvador by averaging their calculations of 79 for Guatemala and 88 for Colombia. Those estimates are not included in the calculations of income differences and do not appear in the table below.Several cases merit specific attention. To obtain a figure for South Africa, the authors averaged IQ studies done on different ethnic groups, resulting in a figure of 72. The figures for Colombia, Peru and Singapore were arrived at in a similar manner. For People's Republic of China, the authors used a figure of 109.4 for Shanghai and adjusted it down by an arbitrary 6 points because they believed the average across China's rural areas was probably less than that in Shanghai. Another figure from a study done in Beijing was not adjusted downwards. Those two studies formed the resultant score for China (PRC).In many cases, the IQ of a country is estimated by averaging the IQs of "neighboring countries" that are not actually neighbors of the country in question. For example, Kyrgyzstan's IQ is estimated by averaging the IQs of Iran and Turkey, neither of which is close to Kyrgyzstan – China, which is a neighbor, is not counted as such by Lynn and Vanhanen. Such arbitrary selections of "neighbors" raise additional questions as to the objectivity of the IQ estimates.[citation needed]To account for the Flynn effect (an increase in IQ scores over time), the authors sometimes adjusted the results of older studies upward by an arbitrary number of points. Because of these arbitrary adjustments and the fact that only limited data were available for most nations, the figures should be considered rough estimates.[citation needed]Country IQ estimate Country IQ estimate Country IQ estimateHong Kong (PRC)107 Russia96 Fiji84South Korea106 Slovakia96 Iran84Japan105 Uruguay96 Marshall Islands84Taiwan (ROC)104 Portugal95 Puerto Rico (US)84Singapore103 Slovenia95 Egypt83Austria102 Israel94 India81Germany102 Romania94 Ecuador80Italy102 Bulgaria93 Guatemala79Netherlands102 Ireland93 Barbados78Sweden101 Greece92 Nepal78Switzerland101 Malaysia92 Qatar78Belgium100 Thailand91 Zambia77China (PRC)100 Croatia90 Congo-Brazzaville73New Zealand100 Peru90 Uganda73United Kingdom100 Turkey90 Jamaica72Hungary99 Indonesia89 Kenya72Poland99 Suriname89 South Africa72Australia98 Colombia89 Sudan72Denmark98 Brazil87 Tanzania72France98 Iraq87 Ghana71Norway98 Mexico87 Nigeria67United States98 Samoa87 Guinea66Canada97 Tonga87 Zimbabwe66Czech Republic97 Lebanon86 Congo-Kinshasa65Finland97 Philippines86 Sierra Leone64Spain97 Cuba85 Ethiopia63Argentina96 Morocco85 Equatorial Guinea59[edit] Special casesIn several cases, actual GDP did not correspond with that predicted by IQ. In these cases, the authors argued that differences in GDP were caused by differences in natural resources and whether the nation used a "planned" or "market" economy.One example of this was Qatar, whose IQ was estimated by Lynn and Vanhanen to be about 78, yet had a disproportionately high per capita GDP of roughly USD $17,000. The authors explain Qatar's disproportionately high GDP by its high petroleum resources. Similarly, the authors think that large resources of diamonds explain the economic growth of the African nation Botswana, the fastest in the world for several decades.The authors argued that the People's Republic of China's per capita GDP of roughly USD $4,500 could be explained by its use of a communist economic system for much of its recent history. The authors also predicted that communist nations who they believe have comparatively higher IQs, including the PRC, Vietnam, and North Korea, can be expected to gain GDP by moving from centrally-planned to market economic systems, while predicting continued poverty for African nations. Recent trends in the economy of the People's Republic of China seem to confirm this prediction, as China's GDP has quadrupled since market reforms in 1978.[edit] Peer-reviewed papers using IQ scores from the bookTo meet Wikipedia's quality standards, this article or section may require cleanup.Please discuss this issue on the talk page, or replace this tag with a more specific message. Editing help is available.This article has been tagged since October 2006.Like many books, IQatWoN's results were not peer-reviewed, but peer review has occurred in subsequent articles.A review of the book in Contemporary Psychology (49 (4). pp389-395. Barnett, Susan M.; Williams, Wendy) stated: "In sum, we see an edifice built on layer upon layer of arbitrary assumptions and selective data manipulation. The data on which the entire book is based are of questionably validity and are used in ways that cannot be justified."The book is sharply criticized in a peer-reviewed paper The Impact of National IQ on Income and Growth [1]. Although critical of the IQ data, for the sake of argument the paper assumes that the data is correct but then criticizes the statistical methods used, finding no effect on growth or income.Another peer-reviewed paper with the same assumption, Intelligence, Human Capital, and Economic Growth: An Extreme-Bounds Analysis [2], finds a strong connection between intelligence and economic growth, although the paper makes no explicit claim that IQ explains most of the difference in growth between nations.In a reanalysis of the Lynn and Vanhanen's hypothesis, Dickerson (in press) finds that IQ and GDP data is best fitted by an exponential function, with IQ explaining approximately 70% of the variation in GDP. Dickerson concludes that as a rough approximation "an increase of 10 points in mean IQ results in a doubling of the per capita GDP."Whetzel and McDaniel (2006) conclude that the book's "results regarding the relationship between IQ, democracy and economic freedom are robust". Moreover, they address "criticisms concerning the measurement of IQ in purportedly low IQ countries", finding that by setting "all IQ scores below 90 to equal 90, the relationship between IQ and wealth of nations remained strong and actually increased in magnitude." On this question they conclude that their findings "argue against claims made by some that inaccuracies in IQ estimation of low IQ countries invalidate conclusions about the relationship between IQ and national wealth."Voracek (2004) used the national IQ data to examine the relationship between intelligence and suicide, finding national IQ was positively correlated with national male and female suicide rates. The effect was not attenuated by controlling for GDP.Barber (2005) found that national IQ was associated with rates of secondary education enrollment, illiteracy, and agricultural employment. The effect on illiteracy and agricultural employment remained with national wealth, infant mortality, and geographic continent controlled.Both Lynn and Rushton have suggested that high IQ is associated with colder climates. To test this hypothesis, Templer and Arikawa 2006 compare the national IQ data from Lynn and Vanhanen with data sets that describe national average skin color and average winter and summer temperatures (see also discussion [3]). They find that the strongest correlations to national IQ were −0.92 for skin color and −0.76 for average high winter temperature. They interpret this finding as strong support for IQ-climate association. Templer and Arikawa 2006 is currently listed as the most downloaded article in Intelligence at ScienceDirect (Jan. - March 2006).[4] Other studies using different data sets find no correlation [5][6].Kanazawa (2006), "IQ and the wealth of states" (in press in Intelligence), replicates across U.S. states Lynn and Vanhanen's demonstration that national IQs strongly correlate with macroeconomic performance. Kanazawa finds that state cognitive ability scores, based on the SAT data, correlate moderately with state economic performance, explaining about a quarter of the variance in gross state product per capita.[7][edit] Critique

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To meet Wikipedia's quality standards, this article or section may require cleanup.Please discuss this issue on the talk page, or replace this tag with a more specific message. Editing help is available.This article has been tagged since October 2006.The figures were obtained by taking unweighted averages of different IQ tests. The number of studies is very limited; the IQ figure is based on one study in 34 nations, two studies in 30 nations. There were actual tests for IQ in 81 nations. In 104 of the world's nations there were no IQ studies at all and IQ was estimated based on IQ in surrounding nations.[8] The number of participants in each study was usually limited, often numbering under a few hundred. The exceptions to this were the United States and Japan, for which studies using more than several thousand participants are available.Studies that were averaged together often used different methods of IQ testing, different scales for IQ values and/or were done decades apart. IQ in children is different although correlated with IQ later in life and many of the studies tested only young children.Many nations are very heterogeneous ethnically. This is true for many developing countries. It is very doubtful that an often limited number of participants from one or a few areas are representative for the population as whole.There are also errors in the raw data presented by authors. The results from Vinko Buj's 1981 study of 21 European cities and the Ghanaian capital Accra used different scaling from Lynn and Vanhanen's. A comparison of the reported to actual data from only a single study found 5 errors in 19 reported IQ scores [9][10].As noted earlier, in many cases arbitrary adjustments were made by authors to account for the Flynn effect or when the authors thought that the studies were not representative of the ethnic or social composition of the nation.There is controversy about whether IQ is a valid measurement of intelligence, especially among third-world populations. (See the article at IQ for details, as well as the article race and intelligence.) It is generally agreed many factors, including environment, culture, demographics, wealth, pollution, and educational opportunities, affect measured IQ. However, the origin of differences in IQ is disputed; according to those positing a partly genetic origin, non-hereditary factors account for anywher from 20-60% of the disparity [11]. Others posit an exclusively non-hereditary origin.One common criticism is that many of the countries with the best average scores are those where testing (e.g. American SATs, baccalaureate examinations) is a crucial aspect of the educational process, and that many of these tests (esp. the SATs) have been shown to be very similar to IQ tests. In these nations, because students study extensively for the high-stakes examinations, it is quite possible that IQ scores are higher because people are subjected to frequent examinations for which they prepare extensively.There are many difficulties when one is measuring IQ scores across cultures, and in multiple languages. First of all, use of the same set of exams requires translation, with all its attendant difficulties. To adapt to this, many IQ testers rely on both verbal tests, involving word analogies and the like, and non-verbal tests, which involve pictures, diagrams, and conceptual relationships (such as in-out, big-small, and so on). Roughly the same results tend to be gained with either approach.The book reports a correlation between IQ and GDP. The book does not explicitly point out other factors which may directly cause the correlation. The Copenhagen Consensus points out that "iodine-deficient individuals score an average of 13.5 points lower in IQ tests." Countries with individuals plagued by iodine deficiency may have other factors depressing IQ, so this finding in isolation does not suggest that such a deficiency alone accounts for 13.5 IQ points. In this case, barring intervention, a nation's poverty may be self-sustaining in cases where successive generations cannot meet basic nutrition requirements.Other factors may serve to heighten poverty while simultaneously decreasing IQ. For example, it is common for teenage children in sub-Saharan Africa to be the primary earners for their family. This is due to AIDS-related deaths of older caregivers. As children leave school to begin subsistence farming, their education ends and IQs will be markedly lower. The book does not adequately address the casual relationship of these outside factors to both poverty and intelligence.Finally, the Flynn effect may well reduce or eliminate differences in IQ between nations in the future. One estimate is that the average IQ of the US was below 75 before factors like improved nutrition started to increase IQ scores. Some predict that considering that the Flynn effect started first in more affluent nations, it will also disappear first in these nations. Then the IQ gap between nations will diminish. However, to take a reductio ad absurdum, that the IQ difference will disappear among the babies born today, the differences will remain for decades simply because of the composition of the current workforce. Steve Sailer noted as much when discussing the workforce in both India and China (see second diagram) [12].[edit] U.S. states and political party hoaxSome sources, such as The Economist, 15th-21st May 2004 (p.44 in the UK edition), have reported a list of average IQs of U.S. states, supposedly from IQ and the Wealth of Nations. In fact, such data do not appear in the book. At about the same time, conservative American commentator Steve Sailer exposed the table as a hoax that had already circulated among hundreds of liberal-leaning blogs and other Internet sites [13]. In the following week's edition of The Economist, the editors admitted their error and stated in the column On the trail that they "were the victim of a hoax." The hoax recurred after the 2004 U.S. election, and it was again falsely attributed to IQ and the Wealth of Nations [14], but the incident prompted yet another hoax—a claim that a computer scientist had compiled a genuine state-by-state chart using SAT and ACT scores [15]. This was allegedly compiled by Psychology "Professor Mark Jones, from Virginia Tech," who does not exist. While there is a faculty member by that name, he is an Assistant Professor in the computer science department [16]. Furthermore, no link to such a study, or evidence that he did such a study, has ever been provided.Sailer and anthropologist Henry Harpending provide a list of mean IQs of U.S. states from 1960, arguing that the scores correlate reasonably with public school 8th graders' achievement test scores on the 2003 National Assessment of Education, and thus may be one of the closest data sets to a national sample of IQ scores (table here; discussion here, also see [17]).[edit] End material[edit] References1. IQ and the Wealth of Nations Richard Lynn, Tatu Vanhanen Praeger, ISBN 0-275-97510-X 2. See [18] 3. International Monetary Fund reported 2004 per capita GDP (PPP). [19] • Barber, N. (2005). "Educational and ecological correlates of IQ: A cross-national investigation". Intelligence 33 (3): 273-284. • Dickerson, R. E.. "Exponential correlation of IQ and the wealth of nations". Intelligence In Press, Corrected Proof. • Hunt, E. & Wittmann, W. (in press) Relations Between National Intelligence and Indicators of National Prosperity. Sixth Annual Conference of International Society for Intelligence Research, Albuquerque, NM. [20] • Templer, D. I. and Arikawa, H. (2006). "Temperature, skin color, per capita income, and IQ: An international perspective". Intelligence 34 (2): 121-139. • Voracek, M. (2004). "National intelligence and suicide rate: an ecological study of 85 countries". Personality and Individual Differences 37 (3): 543-553. • McDaniel, M.A. & Whetzel, D.L. (2005). IQ and the Wealth of Nations: Prediction of National Wealth. Sixth Annual Conference of International Society for Intelligence Research, Albuquerque, NM. [21] • Whetzel, D. L. & McDaniel, M. A.. "Prediction of national wealth". Intelligence 34: 449-458. [edit] See also• The Bell Curve • Race and intelligence • Economic inequality [edit] External links• "Intelligence and the Wealth and Poverty of Nations" - article by Lynn and Vanhanen • PISA scores transformed into IQ values in comparison with IQ estimated by Lynn and Vanhanen • Smart Fraction Theory of IQ and the Wealth of Nations • Exponential correlation of IQ and the wealth of nations - Peer reviewed article to be published in an upcoming edition of Intelligence (journal) • "The Bigger Bell Curve: Intelligence, National Achievement, and The Global Economy", review by J. Philippe Rushton • "A Reader's statistical update of IQ & The Wealth of Nations" • A Few Thoughts on IQ and the Wealth of Nations, Steve Sailer, VDARE, April 2002. Retrieved from "http://en.wikipedia.org/wiki/IQ_and_the_Wealth_of_Nations" POSTED BY GLOBALBELAI7 AT MONDAY, MARCH 24, 2008 0 COMMENTS