People tend to overestimate their romantic partner's intelligence even more than their own
Introduction
Humans can self-estimate their own intelligence with some degree of accuracy (Freund & Kasten, 2012), and the intelligence of others, too, based even on very limited information (Borkenau & Liebler, 1993). However, there is empirical evidence to suggest that humans tend to overestimate their cognitive capacities (the better-than-average effect; Mabe & West, 1982) and, theoretically, possibly the intelligence of their romantic partners (the positive illusion effect; Barelds & Dijkstra, 2009).1 Correspondingly, humans rate intelligence highly in a prospective romantic partner (Buss et al., 1990). Furthermore, assortative mating for intelligence is well established empirically with objective intelligence tests, and, to some degree, with self-estimates of intelligence (Bouchard & McGue, 1981; Escorial & Martín-Buro, 2012). However, precisely how and why assortative mating for intelligence occurs remains an open question (Robinson et al., 2017).
The males-compete/females-choose model of sexual selection (Stewart-Williams & Thomas, 2013) suggests that women should be better at discerning the intelligence of men, in comparison to a man's capacity to discern the intelligence of women. By contrast, the mutual mate model of sexual selection (Stewart-Williams & Thomas, 2013) suggests that women and men should be able to discern each other's intelligence about equally well. To-date, these competing theories have not been tested, in this context. Furthermore, some compatibility relationship theory (Gonzaga, Campos, & Bradbury, 2007; Huston & Houts, 1998) suggests the degree of assortative mating for intelligence across couples should correlate positively with romantic relationship satisfaction, which, arguably, would promote the continuance of assortative mating for intelligence. To-date, this hypothesis has also not been tested extensively.
In light of the above, this investigation had four primary purposes. First, to test for the better-than-average intelligence effect and the positive illusion effect for intelligence in romantic couples. Secondly, to test the males-compete/females-choose model versus the mutual mate choice model, by estimating the association between female ratings of male partner IQ and objective male partner IQ versus the association between male ratings of female partner IQ and objective female partner IQ. Thirdly, we attempted to replicate the assortative mating for intelligence effect with a fluid intelligence test, as well as with a self-estimation of intelligence scale. Finally, we estimated the association between degree of intelligence compatibility (subjective and objective) and relationship satisfaction.
Section snippets
Accuracy of estimating one's own IQ: correlational
A substantial amount of research has established a positive correlation between self-estimated intelligence (SEI) and objectively measured intelligence (r ≈ 0.30; Freund & Kasten, 2012; Gignac, Stough, & Loukomitis, 2004; Zajenkowski, Stolarski, Maciantowicz, Malesza, & Witowska, 2016). Thus, to some degree, people tend to have insight into their intellectual capacity. The correlation is not so large, however, as to suggest that SEI scores may be used as a proxy for objectively measured IQ
Accuracy of estimating one's own IQ: mean difference
Research in the broader area of the self-evaluation of abilities has found that, on average, people overestimate their abilities across a wide range of dimensions (Mabe & West, 1982). The phenomenon is often referred to as the ‘better-than-average-effect’ (Alicke & Govorun, 2005). With respect to intelligence, specifically, Heck, Simons, and Chabris (2018) asked a general community sample of Americans to respond to the following item: ‘I am more intelligent than the average person.’ They found
Accuracy of estimating romantic partner's intelligence
On average, humans state that they value intelligence highly in a prospective romantic partner (Buss et al., 1990). Furthermore, intelligence carries with it biological advantages that can be passed onto children (see Hagenaars et al., 2016, for example). However, in order for sexual selection for intelligence to occur, humans would need to be able to perceive or discern the intelligence of prospective mates with some degree of accuracy. Empirical research suggests that even strangers can
Are women better than men at discerning a romantic partner's intelligence?
According to the males-compete/females-choose model of sexual selection, males compete for the attention of women by displaying biologically and socially valuable characteristics to help women choose a partner with whom to mate (Darwin, 1871; Miller, 2011; Stewart-Williams & Thomas, 2013). Obviously, the characteristics displayed by men need to be perceptible to women, in order to facilitate the decision to choose one man over another. As noted above, some empirical research suggests that even
Assortative mating for intelligence
A positive correlation (r ≈ 0.30 to 0.40) between the objectively measured IQ scores of people in a romantic relationship has been reported (Van Leeuwen, Van den Berg, & Boomsma, 2008; Watson et al., 2004). Furthermore, the correlation does not appear to increase with age of the relationship, suggesting that the effect occurs at the selection stage (Mascie-Taylor, 1989). Consequently, the effect is known as assortative-mating for intelligence (Jensen, 1967). There is some evidence to suggest
Summary
It is well-established that people can predict, to some degree, their own intelligence as well as the intelligence of others. However, despite the observation of the better-than-average effect for several abilities/competencies, the degree to which people may overestimate their own (or their partner's) intelligence has not yet been established, on the basis of comparable self-estimated IQ and objectively estimated IQ scores. Consequently, in the current study, we investigated these effects
Sample
The original sample included 222 couples. However, one case did not have a Raven's IQ score and one case did not have a relationship satisfaction score. These two cases were omitted from the analyses. Additionally, two cases reported their ages as >65, therefore, we excluded these two cases, as well, due to the limitations of the Raven's IQ norms. Thus, the final sample consisted of 218 heterosexual couples (age Mmen = 28.00, SD = 9.25; age Mwomen = 27.27, SD = 9.16) who were recruited from the
Accuracy of IQ estimates
The descriptive statistics are reported in Table 1. As hypothesized, there was a positive correlation between self-estimated intelligence and objective intelligence (APM) for both women (r = 0.26, 95%CI: 0.12/0.38, p < .001) and men (r = 0.33, 95%CI: 0.13/0.49, p < .001). However, as can be seen in Fig. 2, both women and men overestimated their own IQs, when their self-ratings were compared against their performance on the objective IQ test: female mean IQ difference = 29.99 IQ points, 95%CI:
Discussion
We replicated the positive correlation between self-estimated IQ and objective IQ. However, we found that both women and men greatly overestimated their IQ, consistent with the better-than-average effect. People also overestimated their romantic partner's IQ, consistent with the positive illusion effect. We replicated the assortative mating for intelligence effect, on the basis of objectively measured intelligence, and extended the assortative mating for intelligence effect to self-estimated
Limitations
Although the sample size used in this investigation may be regarded as respectable (N = 218; power = 0.85 to detect a typical correlation of 0.20 as significant), unfortunately, established tests of the difference between correlations have been discovered to be underpowered. For example, when the population difference between two dependent non-overlapping correlations is equal to 0.70 vs. 0.60, a sample size of 100 was found to have power of only 0.34 (Silver, Hittner, & May, 2004). Based on
Conclusion
Assortative mating for intelligence is a robust, empirical effect, however, beyond the consistently observed assortative mating for intelligence correlation, relatively little is known about the processes by which the phenomenon arises. Based on the results of this investigation, it appears that both women and men may participate in the process of evaluation and selection, consistent with the mutual mate model of sexual selection.
Acknowledgement
This work was supported from grant no BST2018 funded by Faculty of Psychology of the University of Warsaw.
References (92)
Self-estimates of intelligence: Culture and gender difference in self and other estimates of both general (g) and multiple intelligences
Personality and Individual Differences
(2001)Sex differences in mate selection preferences
Personality and Individual Differences
(2009)Raven's is not a pure measure of general intelligence: Implications for g factor theory and the brief measurement of g
Intelligence
(2015)- et al.
Some people are attracted sexually to intelligence: A psychometric evaluation of sapiosexuality
Intelligence
(2018) - et al.
Openness, intelligence, and self-report intelligence
Intelligence
(2004) - et al.
Effect size guidelines for individual differences researchers
Personality and Individual Differences
(2016) - et al.
A longitudinal study on the stability of self-estimated intelligence and its relationship to personality traits
Personality and Individual Differences
(2017) - et al.
Value priorities and preferences for a relationship partner
Personality and Individual Differences
(2002) - et al.
Perceived female intelligence as economic bad in partner choice
Personality and Individual Differences
(2016) - et al.
Assessing the accuracy of perceptions of intelligence based on heritable facial features
Intelligence
(2017)
Do those who know more also know more about how much they know
Organizational Behavior and Human Performance
Gender differences in self-estimated IQ: The need for care in interpreting group data
Personality and Individual Differences
Evaluating self and partner physical attractiveness
Body Image
A twin-family study of general IQ
Learning and Individual Differences
Why do angry people overestimate their intelligence? Neuroticism as a suppressor of the association between Trait-Anger and subjectively assessed intelligence
Intelligence
Time to be smart: Uncovering a complex interplay between intelligence and time perspectives
Intelligence
Intelligence, personality, and interests: Evidence for overlapping traits
Psychological Bulletin
The better-than-average effect
Positive illusions about a partner's physical attractiveness and relationship quality
Personal Relationships
An assessment of positive illusions of the physical attractiveness of romantic partners
Journal of Social and Personal Relationships
The optimal margin of illusion
Journal of Social and Clinical Psychology
Human aging and duration judgments: A meta-analytic review
Psychology and Aging
Convergence of stranger ratings of personality and intelligence with self-ratings, partner ratings, and measured intelligence
Journal of Personality and Social Psychology
Thin slices of behavior as cues of personality and intelligence
Journal of Personality and Social Psychology
Familial studies of intelligence: A review
Science
Flynn effect and its reversal are both environmentally caused
Proceedings of the National Academy of Sciences
Experiences and attitudes of American adults concerning standardized intelligence tests
International preferences in selecting mates: A study of 37 cultures
Journal of Cross-Cultural Psychology
Sexual strategies theory: An evolutionary perspective on human mating
Psychological Review
A possible model to understand the personality-intelligence interface
British Journal of Psychology
The Descent of Man and Selection in Relation to Sex
The predictive validity of ideal partner preferences: A review and meta-analysis
Psychological Bulletin
The role of personality and intelligence in assortative mating
The Spanish Journal of Psychology
Statistical power analyses using G*Power 3.1: Tests for correlation and regression analyses
Behavior Research Methods
Gender differences in body image are increasing
Psychological Science
How smart do you think you are? A meta-analysis on the validity of self-estimates of cognitive ability
Psychological Bulletin
Sex differences in self-estimates on two validated IQ test subscale scores
Journal of Applied Social Psychology
Sex and culture differences in the estimates of general and multiple intelligence: A study comparing British and Egyptian students
Individual Differences Research
Personality and intelligence: Gender, the big five, self-estimated and psychometric intelligence
International Journal of Selection and Assessment
Correlations between self-estimated and psychometrically measured IQ
The Journal of Social Psychology
Estimates of ten multiple intelligences: Sex and national differences in the perception of oneself and famous people
European Psychologist
Similarity, convergence, and relationship satisfaction in dating and married couples
Journal of Personality and Social Psychology
Shared genetic aetiology between cognitive functions and physical and mental health in UK Biobank (N = 112 151) and 24 GWAS consortia
Molecular Psychiatry
The smarter sex: A critical review of sex differences in intelligence
Educational Psychology Review
65% of Americans believe they are above average in intelligence: Results of two nationally representative surveys
PLoS One
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