Capability to understand one's emotions and use this understanding to guide thinking and behavior
Emotional intelligence (EI), also known as emotional quotient (EQ), is the ability to perceive, use, understand, manage, and handle emotions. High emotional intelligence includes emotional recognition of emotions of the self and others, using emotional information to guide thinking and behavior, discerning between and labeling of different feelings, and adjusting emotions to adapt to environments. This includes emotional literacy.
The term first appeared in 1964, gaining popularity in the 1995 bestselling book "Emotional Intelligence" by psychologist and science journalist Daniel Goleman. Some researchers suggest that emotional intelligence can be learned and strengthened, while others claim that it is innate.
Various models have been developed to measure EI: The "trait model" focuses on self-reporting behavioral dispositions and perceived abilities; the "ability model" focuses on the individual's ability to process emotional information and use it to navigate the social environment. Goleman's original model may now be considered a "mixed model" that combines what has since been modelled separately as "ability EI" and "trait EI".
While some studies show that there is a correlation between high EI and positive workplace performance, there is no general consensus on the issue among psychologists, and no causal relationships have been shown. EI is typically associated with empathy, because it involves a person relating their personal experiences with those of others. Since its popularization in recent decades and links to workplace performance, methods of developing EI have become sought by people seeking to become more effective leaders.
Recent research has focused on emotion recognition, which refers to the attribution of emotional states based on observations of visual and auditory nonverbal cues. In addition, neurological studies have sought to characterize the neural mechanisms of emotional intelligence. Criticisms of EI have centered on whether EI has incremental validity over IQ and the Big Five personality traits. Meta-analyses have found that certain measures of EI have validity even when controlling for both IQ as well as personality.
History.
The concept of "emotional strength" was introduced by Abraham Maslow in the 1950s. The term "emotional intelligence" may have first appeared in a 1964 paper by Michael Beldoch and a 1966 paper by B. Leuner.
In 1983, Howard Gardner's "Frames of Mind: The Theory of Multiple Intelligences" introduced the idea that traditional types of intelligence, such as IQ, fail to fully explain cognitive ability. He introduced the idea of multiple intelligences, which included both interpersonal intelligence and intrapersonal intelligence, which he respectively defined as the capacity to understand others and oneself.
The first published use of the term "EQ" (emotional quotient) is in an article by Keith Beasley in 1987 in the British Mensa magazine.
In 1989, Stanley Greenspan proposed a model to describe EI. The following year, Peter Salovey and John Mayer proposed another model.
The term became widely known with the publication of Daniel Goleman's 1995 book: "Emotional Intelligence – Why it can matter more than IQ". Goleman followed up with several similar publications that reinforce use of the term. Late in 1998, Goleman's "Harvard Business Review" article entitled "What Makes a Leader?" caught the attention of senior management at Johnson &amp; Johnson's Consumer Companies. The article argued that EI comprised the skills and characteristics that drive leadership performance. Johnson &amp; Johnson funded a study which concluded that there was a strong relationship between superior performing leaders and emotional competence, supporting theorists' suggestions that the EI is a distinguishing factor in leadership performance.
Tests measuring EI have not replaced IQ tests as a standard metric of intelligence. In later research, EI has received criticism regarding its purported role in leadership and business success.
Definitions.
Emotional intelligence has been defined by Peter Salovey and John Mayer as "accurately perceiving emotion, using emotions to facilitate thought, understanding emotion, and managing emotion". The concept comprises both emotional and intellectual processes. 
Emotional intelligence also reflects an ability to use intelligence, empathy, and emotions to enhance understanding of interpersonal dynamics. However, substantial disagreement exists regarding the definition of EI, with respect to both terminology and operationalization. Currently, there are three main models of EI: The "ability model" defines EI in terms of cognitive and emotional abilities; the "mixed model", introduced by Daniel Goleman, comprises a variety of emotional competencies, sometimes being regarded as a form of trait EI; the "trait model" defines EI as comprising traits within a personality trait theory framework.
Different models of EI have led to the development of various instruments for the assessment of the construct. While some of these measures may overlap, most researchers agree that they relate to different constructs.
Models.
Based on theoretical and methodological approaches, EI measures are categorized in three main streams: ability-based measures (e.g. MSCEIT), self-reports of abilities measures (e.g. SREIT, SUEIT and WLEIS), and mixed-models (e.g. AES, ECI, EI questionnaire, EIS, EQ-I and GENOS), which include measures of EI and traditional social skills. 
Ability model.
Salovey and Mayer's define EI within the confines of the standard criteria for a new intelligence. Their initial definition of EI had been "the ability to monitor one's own and other people's emotions, to discriminate between different emotions and label them appropriately, and to use emotional information to guide thinking and behavior". They later revised the definition to "the ability to perceive emotion, integrate emotion to facilitate thought, understand emotions, and to regulate emotions to promote personal growth." After further research, their definition of EI evolved into "the capacity to reason about emotions, and of emotions, to enhance thinking. It includes the abilities to accurately perceive emotions, to access and generate emotions so as to assist thought, to understand emotions and emotional knowledge, and to reflectively regulate emotions so as to promote emotional and intellectual growth."
The ability-based model views emotions as useful sources of information that help one to make sense of and navigate the social environment, with EI abilities manifesting in adaptive behaviors. It proposes that individuals vary in their ability to process information of an emotional nature and in their ability to relate emotional processing to wider cognition.
The model claims that EI includes four types of abilities:
The ability EI model has been criticized for lacking face and predictive validity in the workplace. However, in terms of construct validity, ability EI tests have great advantage over self-report scales of EI because they compare individual maximal performance to standard performance scales and do not rely on individuals' endorsement of descriptive statements about themselves.
Measurement.
The current measure of Mayer and Salovey's model of EI, the Mayer–Salovey–Caruso Emotional Intelligence Test (MSCEIT), is based on a series of emotion-based problem-solving items. Consistent with the model's claim of EI as a type of intelligence, the test is modeled on ability-based IQ tests. By testing a person's abilities on each of the four branches of emotional intelligence, it generates scores for each of the branches as well as a total score.
Central to the four-branch model is the idea that EI requires attunement to social norms. Therefore, the MSCEIT is scored in a consensus fashion, with higher scores indicating higher overlap between an individual's answers and those provided by a worldwide sample of respondents. The MSCEIT can also be expert-scored so that the amount of overlap is calculated between an individual's answers and those provided by a group of 21 emotion researchers.
Although promoted as an ability test, the MSCEIT test is unlike standard IQ tests in that its items do not have objectively correct responses. Among other challenges, the consensus scoring criterion means that it is impossible to create items that only a minority of respondents can solve, because, by definition, responses are deemed emotionally "intelligent" only if the majority of the sample has endorsed them. This and other similar problems have led some cognitive ability experts to question the definition of EI as a genuine intelligence.
In a study by Føllesdal, the MSCEIT test results of 111 business leaders were compared with how their employees described their leader. It was found that there were no correlations between a leader's test results and how he or she was rated by the employees, with regard to empathy, ability to motivate, and leader effectiveness. Føllesdal also criticized the Canadian company Multi-Health Systems, which administers the test. The test contains 141 questions, but it was found after publishing the test that 19 of these did not give the expected answers. This has led Multi-Health Systems to remove answers to these 19 questions before scoring.
Other measurements.
Various other specific measures also assess ability in emotional intelligence. These include:
Mixed model.
The model introduced by Daniel Goleman focuses on EI as a wide array of competencies and skills, which drive leadership performance in applied settings. Goleman's model outlines five main EI constructs:
Goleman includes a set of emotional competencies within each construct of EI. Emotional competencies are learned capabilities that must be developed to achieve performance. Goleman posits that individuals are born with a general emotional intelligence that determines their potential for learning emotional competencies.
Criticism.
Goleman's model of EI has been criticized in the research literature as "pop psychology".
Goleman's early work has been criticized for assuming that EI is a type of intelligence or cognitive ability. Eysenck writes that Goleman's description of EI contains unsubstantiated assumptions about intelligence in general and that it even runs contrary to what researchers have come to expect when studying types of intelligence. Similarly, Locke claims that the concept of EI is a misinterpretation of the intelligence construct, and he offers an alternative interpretation: it is not another form or type of intelligence, but intelligence—the ability to grasp abstractions—applied to a particular life domain: emotions. He suggests the concept should be re-labeled and referred to as a skill.
Measurement.
Two measurement tools are based on the Goleman model:
Trait model.
Konstantinos V. Petrides proposed a conceptual distinction between the ability-based model and a trait-based model of EI, developing the latter over many years in a number of publications. Trait EI is an individual's self-perceptions of their emotional abilities — as defined by Petrides, "a constellation of emotional self-perceptions located at the lower levels of personality." This definition of EI encompasses behavioral dispositions and self-perceived abilities. It is measured by self report, as opposed to the ability-based model which attempts to measure actual abilities, which have proven resistant to scientific measurement. Trait EI is investigated within a personality framework. An alternative label for the same construct is trait emotional self-efficacy.
The trait EI model is general and subsumes the Goleman mixed model. The conceptualization of EI as a personality trait leads to a construct that lies outside the taxonomy of human cognitive ability, distinguishing its operationalization and theory from other models.
Measurement.
There are many self-report measures of EI, including the EQ-i, the Swinburne University Emotional Intelligence Test (SUEIT), and the Schutte EI model. As limited measures of trait emotional intelligence, these models do not assess intelligence, abilities, or skills. The most widely used and widely researched measure of self-report or self-schema emotional intelligence is the EQ-i 2.0. Originally known as the BarOn EQ-i, it was the first self-report measure of emotional intelligence available, and the only measure predating Goleman's bestselling book.
The Petrides model is operationalized by the Trait Emotional Intelligence Questionnaire (TEIQue), which encompasses 15 subscales organized under four factors: well-being, self-control, emotionality, and sociability. In a 2007 study, the psychometric properties of the TEIQue have been found to be normally distributed and reliable. Researchers have found TEIQue scores to be unrelated to Raven's matrices of non-verbal reasoning, which has been interpreted as support for the personality trait view of EI. TEIQue scores have also been found to be positively related to extraversion, agreeableness, openness, conscientiousness, while being inversely related to alexithymia, neuroticism. A number of quantitative genetic studies have been carried out within the trait EI model, which have revealed significant genetic effects and heritabilities for all trait EI scores. Two studies involving direct comparisons of multiple EI tests yielded favorable results for the TEIQue.
Correlations.
A review published in the "Annual Review of Psychology" in 2008 found that higher emotional intelligence is positively correlated with a number of outcomes, including social relations, academic achievement, negotiation skills, workplace social dynamics, positive perceptions by other people, health and wellbeing. It also found EI to be negatively correlated with anti-social and deviant behavior in children as well as poor health behaviors. However, once IQ is taken into account, EI does not generally result in higher grades. Additionally, subsequent research has argued that EI leads to better self awareness, decision making, and self-actualization ability.
Gender differences