The concept of intelligence and what exactly it means for a person to be intelligent are the subject of considerable controversy and debate. In general, people consider intelligence to be highly desirable, hence the controversy about how to define it. Some theorists have argued that intelligence is also linked with socially desirable personality traits, although this is debatable. Still others have argued that academic definitions of intelligence, based on IQ tests are overly narrow and do not reflect how ordinary people understand what makes a person intelligent. A survey of laypeople’s beliefs about the qualities possessed by an intelligent person did find that people associated intelligence with a number of socially desirable personality traits that are unrelated to IQ. However, an exception to this trend was that laypeople think that intelligent people may be lacking in traits related to agreeableness, particularly, trust, honesty and obedience to social rules. This is in spite of the fact that these traits are also considered socially desirable. Other research has found that people who consider themselves to be highly intelligent also tend to be disagreeable. This suggests that according to lay beliefs smart people are not necessarily nice and that stereotypes about intelligence are not completely socially desirable. Perhaps intelligence and socially desirable personality traits serve different functions, which sometimes conflict with each other.
Although personality and intelligence have customarily been considered by psychologists to be distinct and separate domains of human functioning, more recent research efforts have examined how they might be related. According to one approach known as Life History Theory, a wide range of human characteristics, including personality and intelligence, vary together along a single continuum known as the K-factor due to natural selection for a certain set of traits during human evolution (Dunkel, Cabeza De Baca, Woodley, & Fernandes, 2014). I have explained this theory in more detail in a previous post. What is most relevant here is that the proponents of this theory argue for the existence of a general factor of personality that combines all the major features of personality in a specific socially desirable way. In terms of the Big Five model for example, a general factor combines extraversion, agreeableness, conscientiousness, openness to experience, and emotional stability (the opposite pole of neuroticism) into a single dimension along which people tend to vary, with the high pole being associated with high self-esteem, subjective well-being, and social desirability. Going further, some researchers have argued that this general factor of personality (GFP) is also associated with general intelligence (e.g. Dunkel, 2013; Irwing, Booth, Nyborg, & Rushton, 2012).
If this theory is correct, it seems to imply that those lucky people who are high in the K-factor possess all the advantages, having both great personalities and high intelligence, while those low in the K-factor have drawn the short end of life’s stick in most important respects. However, the existence of a general factor of personality is still being debated and has a number of conceptual problems as I have discussed in a previous post on the subject. Additionally, as I discussed in a follow-up post, socially desirable personality traits have both strengths and weaknesses, while the ‘dark side’ of personality can often be strangely attractive (Sherman, Figueredo, & Funder, 2013).
Furthermore, the results of multiple studies show that not all of the Big Five traits that are supposed to make up the general factor of personality are positively correlated with intelligence (DeYoung, 2011). Openness to experience has the largest positive correlation (about .30), emotional stability has a more modest correlation (around .15), and extraversion has been found to have a very small correlation (.08). On the other hand, conscientiousness actually has been found to have a negative correlation with intelligence (-.12) while agreeableness is unrelated to intelligence (average correlation of .01). Colin DeYoung has argued that the small positive correlation between extraversion and intelligence might be purely a statistical artefact that occurs because extraversion and openness to experience are also positively correlated. Hence the apparent association between extraversion and intelligence might be an illusory one that is simply due to extraversion being correlated with a trait that also happens to be correlated with intelligence. Considering that a general factor of personality combines some traits that are positively correlated with intelligence and others that are not (including conscientiousness which has a negative correlation), then it is also possible that the apparent correlation between the GFP and intelligence occurs primarily due to the inclusion of openness to experience in the mix of traits.
However, some people object that intelligence tests are based on an overly narrow understanding of the concept of intelligence that does not encompass all the qualities that ordinary people understand when they think of intelligent behavior. Limited associations between intelligence and personality traits other than openness to experience might reflect the narrow focus of the tests used. Perhaps a broader definition of intelligence might reveal more linkages with personality? Critics of IQ testing, such as Robert Sternberg and Howard Gardner have argued that these tests measure a limited set of skills related to analytical thinking and do not take into consideration other skills that might be required to behave intelligently. In support of this, Sternberg (1985) conducted a number of surveys asking people to describe the qualities possessed by an intelligent person. Summarising very briefly, participants thought that intelligent behavior involves a combination of problem-solving ability, verbal ability, social competence, and motivation (e.g. to learn and achieve). While problem solving and verbal ability are assessed by IQ tests, social competence and motivation are outside the purview of IQ testing. On the other hand they are associated with personality traits, such as extraversion, agreeableness and conscientiousness.
A more recent study in Estonia looked more explicitly at what personality traits lay people believe are associated with personality (Mõttus, Allik, Konstabel, Kangro, & Pullmann, 2008). Participants were asked to rate how a person of high intelligence would compare with a person of low intelligence in regard to their personality traits. Two types of intelligence were specified, ‘academic’ (ability to gain new knowledge and skills easily) and ‘practical’ (ability to solve everyday problems) intelligence. The Big Five were each assessed in regards to six specific facets, making a total of 30 specific traits in all. A separate group of participants were asked to rate the socially desirability of each of these traits. The results found were that people regarded as highly intelligent, in either an academic or a practical sense, were thought to be more extraverted, emotionally stable, conscientious, and open to experience compared to those who were low in intelligence. However, highly intelligent people were not necessarily more agreeable in all respects. In particular, highly intelligent people were regarded as less trusting of others, and less compliant with rules. People high in academic intelligence were regarded as no different in honesty and modesty compared to those lower in ability, while those who were high in practical intelligence were regarded as more honest, but considerably less modest than those lower in practical ability. Trust, honesty, compliance, and modesty were all rated as socially desirable qualities, yet participants in this study did not considered them to be particularly characteristic of intelligent persons. Hence, one might say that having these particular qualities is considered ‘nice’ but not necessarily ‘smart’.
The authors of this study noted that these findings might be specific to Estonian people and need to be replicated in other cultures. If they are generally true, they suggest that lay people do not necessarily assume that socially desirable traits in general, especially prosocial traits, are particularly indicative of intelligence. Perhaps this reflects an implicit belief that highly intelligent people feel that they can succeed in life without following the same rules that other people do, do not place as much trust as most people do in others, and are not overly modest about their abilities. Further evidence that people do not entirely associate intelligence with socially desirable personality traits derives from a study using an international sample in which people were asked to self-estimate their own intelligence (Furnham & Buchanan, 2005). Previous research has found that people can estimate their own IQ with a moderate amount of accuracy, although their estimates tend to be biased to some extent by their level of self-esteem for example, and that men tend to give higher estimates of their own intelligence compared to women. This study also found that self-estimates of overall intelligence (IQ) correlated with participants’ own personality traits. Specifically, those who gave higher self-estimates of their intelligence tended to be more open to experience and emotionally stable, but also more introverted and disagreeable. As noted earlier, actual IQ is positively correlated with openness to experience and emotional stability, but is unrelated to agreeableness and only weakly associated with extraversion. Perhaps people who consider themselves highly intelligent (whether or not they really are) do not believe in false modesty or otherwise think there is something disagreeable about being intelligent. In addition to obtaining self-estimates of IQ, participants were asked to rate themselves on ten different abilities based on Howard Gardner’s theory of multiple intelligences (which theory I critically analysed in a previous post). Hence, this study allowed people to rate their ‘intelligence’ in very broad, generous ways, well beyond the limits of IQ tests. Factor analysis of these 10 abilities showed that they could be grouped into two distinct factors. One factor the authors called academic-cognitive and comprised logical, spatial, naturalistic and verbal ‘intelligences’, while the other factor, which they called social-emotional, comprised interpersonal, intrapersonal, existential, spiritual, bodily-kinesthetic, and musical ‘intelligences’. All of the 10 individual abilities were each correlated with one or more of the Big Five personality traits (in fact interpersonal was correlated with all five traits). For example, openness to experience was positively correlated with nine of the intelligences, while neuroticism was negatively correlated with six of them. Interestingly, agreeableness was negatively correlated with logical and spatial intelligences, and positively correlated with interpersonal and spiritual intelligences. This suggests that agreeable people may feel they are able to understand others and have a spiritual influence on them, but feel less confident of their ability to reason logically and solve mathematical or spatial problems. Further analysis found that the academic-cognitive factor was most strongly associated with introversion, disagreeableness, emotional stability, and openness to experience, while the social-emotional factor was most strongly associated with extraversion and openness to experience. In summary, this suggests that openness to experience and to a lesser extent emotional stability are associated with rating oneself as “intelligent” in a wide variety of senses. However, according to this study, people who consider themselves to be highly “intelligent” in an academic sense tend to be introverted and disagreeable, while those who believe they are more socially and emotionally “intelligent” tend to be extraverted and (to an extent) more agreeable. These findings therefore suggest that lay people do not think of intelligence (particularly in the academic sense, which is also the most scientifically well-established sense of the term) as something that is necessarily associated with uniformly socially desirable personality traits that are supposed to make up a general factor of personality. Similarly to the Estonian study, this study seems to suggest that people tend to associate intelligence with disagreeable qualities, although the two studies provide somewhat conflicting results concerning the perceived relationship between extraversion and intelligence.
In conclusion, theories that propose that all socially desirable personality traits are associated with intelligence as part of a super-K dimension would seem to have some problems. If one’s definition of intelligence is limited to what is measured by objective ability tests, such as IQ, there is the problem that the major dimensions of personality, such as those making up the Big Five are not all positively correlated with intelligence. On the other hand, if one attempts to use a broader definition that is more in line with lay persons' understanding of intelligence, inconsistencies still emerge. Agreeableness in particular, a trait associated with prosocial qualities such as trust and obedience to social acceptable standards of behavior, seems to be somewhat incompatible with lay people’s beliefs about the qualities possessed by an intelligent person. Perhaps this reflects an understanding that most people have that what is good for society is not always good for an individual, a theme I have explored in a previous post about the allure of the dark side of personality. Additionally, super-K theories assume that there is a single adaptive set of characteristics (a high general factor of personality combined with high intelligence) that has been selected for by evolution. An alternative model is that there might be a variety of adaptive strategies that people might have that allow them to succeed in life. For example, it has been argued that people who are not highly intelligent might compensate by developing conscientious traits and vice versa that highly intelligent people do not need to work as hard as others to be successful (Moutafi, Furnham, & Paltiel, 2004). Perhaps in a similar vein, lay people have an implicit understanding that there might be a variety of paths to success in life that people with somewhat diverse traits can pursue.
 Researchers have also derived this general factor of personality from other personality inventories besides the Big Five. Because the Big Five is currently the most well-established trait model, it is the one that I will focus upon here.
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Other posts discussing intelligence and its connections with personality
Emotional intelligence is not relevant to understanding psychopaths Tests of emotional intelligence assess social conformity
The Knowledgeable Personality Openness to experience is the strongest personality predictor of general knowledge
Personality, Intelligence and “Race Realism” The inverse relationship between conscientiousness and intelligence
Cold Winters and the Evolution of Intelligence – A critique of Richard Lynn’s Theory
The Illusory Theory of Multiple Intelligences – A critique of Howard Gardner’s theory
DeYoung, C. G. (2011). Intelligence and Personality. In R. J. Sternberg, & Kaufman, S. B. (Ed.), The Cambridge handbook of intelligence (pp. 711-737). New York: Cambridge University Press.
Dunkel, C. S. (2013). The general factor of personality and general intelligence: Evidence for substantial association. Intelligence, 41(5), 423-427. doi: http://dx.doi.org/10.1016/j.intell.2013.06.010
Dunkel, C. S., Cabeza De Baca, T., Woodley, M. A., & Fernandes, H. B. F. (2014). The General Factor of Personality and general intelligence: Testing hypotheses from Differential-K, Life History Theory, and strategic differentiation–integration effort. Personality and Individual Differences, 61–62(0), 13-17. doi: http://dx.doi.org/10.1016/j.paid.2013.12.017
Irwing, P., Booth, T., Nyborg, H., & Rushton, J. P. (2012). Are g and the General Factor of Personality (GFP) correlated? Intelligence, 40(3), 296-305. doi: 10.1016/j.intell.2012.03.001
Mõttus, R., Allik, J., Konstabel, K., Kangro, E.-M., & Pullmann, H. (2008). Beliefs about the relationships between personality and intelligence. Personality and Individual Differences, 45(6), 457-462. doi: http://dx.doi.org/10.1016/j.paid.2008.05.029
Moutafi, J., Furnham, A., & Paltiel, L. (2004). Why is Conscientiousness negatively correlated with intelligence? Personality and Individual Differences, 37(5), 1013-1022. doi: 10.1016/j.paid.2003.11.010
Sherman, R. A., Figueredo, A. J., & Funder, D. C. (2013). The Behavioral Correlates of Overall and Distinctive Life History Strategy. Journal of Personality & Social Psychology, advance online publication. doi: 10.1037/a0033772
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