NO RELATIONSHIP BETWEEN INTELLIGENCE AND FACIAL ATTRACTIVENESS IN A LARGE, GENETICALLY INFORMATIVE SAMPLE

Abstract

Theories in both evolutionary and social psychology suggest that a positive correlation should exist between facial attractiveness and general intelligence, and several empirical observations appear to corroborate this expectation. Using highly reliable measures of facial attractiveness and IQ in a large sample of identical and fraternal twins and their siblings, we found no evidence for a phenotypic correlation between these traits. Likewise, neither the genetic nor the environmental latent factor correlations were statistically significant. We supplemented our analyses of new data with a simple meta-analysis that found evidence of publication bias among past studies of the relationship between facial attractiveness and intelligence. In view of these results, we suggest that previously published reports may have overestimated the strength of the relationship and that the theoretical bases for the predicted attractiveness-intelligence correlation may need to be reconsidered.

Keywords: evolutionary genetics; facial attractiveness; fitness trait; genetic correlation; intelligence; twin and family study.

Figure 1

The estimated strength of the relationship between attractiveness and intelligence tends to decrease as log₁₀ sample size increases (r = −.41, df = 28, p = .03), consistent with the possibility of a bias in favor of publishing small, underpowered studies that overestimated the magnitude of the correlation. In this analysis, we included only independently estimated effects. Frieze et al. (1990) and Zebrowitz and Rhodes (2004) each used only two non-overlapping samples to estimate four and eight correlations, respectively; we applied the Fisher transformation to these correlations (i.e., computed a z for each correlation, found the mean of all zs obtained from the same sample, then transformed the mean z back to a correlation) to arrive at independent estimates for inclusion in this analysis. We omitted Kanazawa’s (2011) results as well as the third entry for Felson (1980), because attractiveness and intelligence were not assessed independently in those studies (Table 1).