by Laura Weis with permission
Source: by Laura Weis with permission

How clever are you? What would you score on a fair intelligence test? Are you likely to over- or under-estimate your score. Over the last fifteen years there have been a number of studies on the self-estimation of intelligence.

The literature in this area covers a number of quite specific topics. Some studies have examined sex differences in ratings of overall IQ, nearly all of which have shown a sex difference of between 4 to 9 IQ points.  Males rate their own IQ higher than do females and students higher than working adults.  Other studies have looked at sex differences in the ratings of relatives, specifically grandparents, parents, siblings and children. They show a consistent sex difference with female relatives being rated as less intelligent than male relatives. Further, people seem to believe there are distinct generational differences, each generation both becoming more intelligent than the past generation and providing higher self-estimates by around 5 to 8 points.

There have also been a number of studies that have examined the relationship between self-estimated and psychometrically measured IQ .The results show that when outliers are removed, the correlations are typically in the range  r = 0.20 to r = 0.50 depending on the sample size and IQ test used. A few studies have examined the relationship between estimated intelligence and personality differences. One showed extraverts tended to give higher self-estimates than introverts particularly for social and artistic intelligence. Another found three personality traits (Stability, Openness, Disagreeableness) accounted for 17% of the variance in self-estimated intelligence.

Recent studies have examined self-estimates of primary mental abilities as defined by IQ test constructors. These results suggest that the sex difference in estimated IQ is limited to areas measuring mathematical and spatial intelligence (Furnham, 2001).  Data have been collected from nearly all the continents and over 20 countries: Africa (Namibia, South Africa, Uganda, Zambia, Zimbabwe), America (United States), Argentina, Asia (Hong Kong, Japan, Singapore), Europe (Belgium, Germany, Poland, Slovakia, United Kingdom), New Zealand and the Middle East (Iran). These studies have found both sex and culture differences but few interactions between the two.      

As well as rating overall intelligence a number of studies have looked at estimates of specific types of intelligence like emotional intelligence, ‘successful’ intelligence, and multiple intelligence.

To summarise my findings from over 40 studies in this area:

First, males of all ages and backgrounds tend to estimate their (overall) general intelligence about 5 to 15 IQ points higher than do females. Always those estimates are above average and usually around one standard deviation above the norm. The argument has been that males are socialised into hubris and females humility with respect to their own intelligence. We know this because the data show little or no difference between the sexes on IQ test scores

Second, when judging “multiple intelligences” males estimate their spatial and mathematical (numerical) intelligence higher but emotional intelligence lower than do females. On some multiple intelligences (verbal, musical, body-kineasthetic) there is little or no sex difference.

Third, people believe these sex difference occur across the generations: people believe their grandfather was/is more intelligent than their grandmother; their father more than their mother; their brothers more than their sisters; and their sons more than their daughters. That is, throughout the generations in one’s family, males are judged more intelligent than females. It is particularly surprising that currently many parents (particularly fathers) think their sons are brighter than their daughters.

Fourth, sex differences are cross-culturally consistent. While Africans tend to give higher estimates, and Asians lower estimates there remains a sex difference across all cultures. Differences seem to lie in cultural definitions of intelligence as well as norms associated with humility and hubris. It seems that the more the culture believes intelligence is associated with cumulative knowledge (crystalised intelligence) and wisdom rather than speed and efficiency of information processing (fluid intelligence) the more highly people rate themselves.

Fifth, the correlation between self-estimated and test generated IQ is positive and low in the range of r=.2 to r=.5 suggesting that you cannot use test scores as proxy for actually scores.

Sixth, with regard to outliers, those who score high on IQ but give low self-estimates tend nearly always to be female, while those with the opposite pattern (high estimates, low scores) tend to be male.

Seventh, most people say they do not think there are sex differences in intelligence, but those who have taken tests and received feedback seem to give themselves higher scores.

Some of my studies in the area

Furnham, A. (2001). Self-estimates of intelligence: Culture and gender difference in self and other estimates of both general (g) and multiple intelligences. Personality and Individual Differences, 31, 1381–1405.

Furnham, A. (2005). Gender and personality differences in self- and other ratings of business intelligence. British Journal of Management, 16, 91-103.

Furnham, A. (2011). Gender differences in self-estimates of general, mathematical, spatial and verbal intelligence. Four meta analyses. Learning and Individual Differences, 21, 493-504.

Furnham, A & Akande, D. (2004). African parents’ estimates of their own and their children’s multiple intelligences. Current Psychology, 22, 281-294.

Furnham, A. & Chamorro-Premuzic, T. (2005). Estimating one’s own and one’s relatives’ multiple intelligence: A study from Argentina. Spanish Journal of Psychology, 8, 12-20.

Furnham, A. & Gasson, L. (1998). Sex differences in parental estimates of their children’s intelligence. Sex Roles, 38, 151-162.

Furnham, A., Hosoe, T. & Tang, L. P. (2001). Male hubris and female humility? A cross-cultural study of ratings of self, parental and sibling multiple intelligence in America, Britain and Japan. Intelligence, 30, 101-115.

Furnham, A., Kidwai, A., & Thomas, C. (2001). Personality, psychometric intelligence and self-estimated intelligence. Journal of Social Behaviour and Personality, 16, 97–114

Furnham, A., Kosari, A. & Swami, V. (2012). Estimates of self, parental and partner multiple intelligences in Iran. Iran Journal of Psychiatry, 7, 22-29.

Furnham, A. & Mkhize, N. (2003). Zulu mothers’ beliefs about their own and their children’s intelligence, Journal of Social Psychology, 143, 83-94.

Furnham, A. & Shagabutdinova, K. (2012). Sex differences in estimating multiple intelligences in self and others: A replication in Russia. International Journal of Psychology, 47, 1-12.

Furnham, A. & Thomas, C. (2004). Parents’ gender and personality and estimates of their own and their children’s intelligence. Personality and Individual Differences, 37, 87–903.

Furnham, A., Tu, B. L. & Swami, V. (2012). Cross-cultural differences in self-assessed intelligence: A comparison of British and Chinese undergraduates. Psychologia, 55, 21-27.

Furnham, A., & Ward, C. (2001). Sex Differences, test experience and the self-estimation of multiple intelligence. New Zealand Journal of Psychology, 30, 52-59.

Furnham, A., Wytykowska, A., & Petrides, K. V. (2005). Estimates of multiple intelligences: A study in Poland. European Psychologist, 10, 51–59.

About the Author

Adrian Furnham, Ph.D.

Adrian Furnham, Ph.D., is a professor of psychology at University College London and the Norwegian Business School.

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