Segall et al (1999) disagreed with Jensen’s theory suggesting that environmental factors could account for the majority of the difference including the bias “against, blacks and other minorities” used within the tests. According to Gross (1999) the “cultural background differ from that of the test’s normative sample (whites).” There is however, a strong correlation between individual differences in I.Q. or within-group differences and genetic factors. Where as group differences or between group differences seem to be largely a result of environmental factors.
Jensen’s response to this suggestion is to “appeal to the studies in which environmental factors are controlled.” An example of this is a study carried out by Shuey (1966) compared the I.Q. results of working-class and middle-class “blacks” and “whites.” His results suggested that the same gap of 15- points difference was present within both classes. He suggested that this shows that genetic factors are more consequential than environmental factors.
However, Bodmer (1972) pointed out that environmental factors do not purely consist of class, (as class merely consists of occupation and income), he also pointed out that ‘black people, have a history of slavery and continued prejudge and discrimination within the past and present. Therefore, their experiences of life regardless of class cannot be considered equivalent to that of their white counterparts. “Measuring the environment only by standard socioeconomic parameters is…like trying to assess the character of an individual by his height, weight and eye colour” (Bodmer, 1972)
Brody’s research (1992) suggested that the environment in which African children are typically raised differs significantly from that of white European children. Brody’s statistics suggest that African children are more likely to have a lower birth weight, have higher levels of poor nutrition and higher blood levels of lead. They are also less likely to be read or to receive intellectual stimulation; these factors are well-known characteristics linked to low I.Q scores.
However, research carried out by the mixed-race adoption studies (Scarr & Weinberg, 198) Weinberg, Scarr and Waldman (1992) suggest that African children adopted shortly after birth have only a slightly lower I.Q. score than ‘white ‘ children adopted into the same family. They suggested that it is the teaching of children that affects their I.Q. scores. Schools are designed to teach children a particular form of intellectual activities, where are minority cultures including African raise their children with emphasis on different type of intellectual activities not covered in I.Q. tests.
Stevenson and Lee (1990) suggest that it is the cultural beliefs that affect I.Q scores. Within Asian cultures, they do not believe in innate abilities, but focusing on encouragement and hard work. They suggest this is the reason why Asians achieve better I.Q. scores that cultures that focus more on natural abilities.
Although the I.Q. tests seem to favour the ‘white Europeans’ over other ethnic minorities, it is actually the Chinese and Japanese children who consistently perform better on I.Q. tests. (Geary, Bow-Thomas, Fan & Siegler (1993) Stevenson et al, (1990): sue & Okazaki, 1990) Therefore, there is evidence that I.Q. test do not cater for children who are brought up in ethnic minority cultures, especially Africans.