Observer-rated physical attractiveness generally predicted individuals’ support of the theoretical evolutionary psychology principles better than did gender, political orientation, or self-esteem

Ward A, English T, Chin M (2021) Physical attractiveness predicts endorsement of specific evolutionary psychology principles. PLoS ONE 16(8): e0254725. August 4, 2021. https://doi.org/10.1371/journal.pone.0254725

Abstract: Evolutionary psychology has emerged as a controversial discipline, particularly with regard to its claims concerning the biological basis of sex differences in human mate preferences. Drawing on theories of motivated inference, we hypothesized that those who are most likely to be privileged by specific aspects of the theory would be most likely to support the theory. In particular, we predicted that physical attractiveness would be positively associated with endorsement of predictions of evolutionary psychology concerning mating strategies. Two studies confirmed this hypothesis. In Study 1, participants rated as higher in physical attractiveness were more likely to support specific principles of evolutionary psychology. In Study 2, a manipulation designed to boost self-perceived physical attractiveness increased endorsement of those same principles. Observer-rated physical attractiveness generally predicted individuals’ support of the theoretical principles better than did gender, political orientation, or self-esteem. Results suggest that those most likely to benefit according to certain predictions of evolutionary psychology are also those most likely to be sympathetic toward its relevant principles.

General discussion

Across two studies, attractiveness—either judged by raters or self-reported—was associated with a greater likelihood of endorsing evolutionary psychology. In a separate study, we ruled out the possibility that attractiveness renders individuals significantly more likely to endorse any controversial theory, finding that the Study 2 manipulation did not lead participants to preferentially endorse the precepts of psychoanalysis or support critiques of biological approaches in psychology.

Comparing the results of Study 1 and Study 2

It is important to reiterate a key difference between the methods of Study 1 and Study 2. In Study 1, outside raters actually evaluated the physical attractiveness of each participant. In Study 2, by contrast, participants themselves were asked to indicate how a typical observer would rate their attractiveness. Nevertheless, the results of Study 1 and Study 2a both showed that higher ratings of attractiveness were associated with greater endorsement of particular aspects of evolutionary psychology (though, interestingly, the effect was stronger in Study 1 than in Study 2a).

To assess the overall effect across the two studies, we conducted a mini meta-analysis [23]. This analysis yielded a combined r of.19, a small-to-medium effect size that, using the Stouffer formula [24], was highly statistically significant, p < .001. In addition, it is perhaps worth noting that the findings across both studies, though differing in effect size, would seem to be highly consistent with one another, unless one were to argue that those who are rated as more physically attractive (Study 1) also somehow possess no awareness that they are seen as more attractive by others (Study 2a) or even worse, somehow think they are seen as less attractive by others than do those who are rated as less physically attractive. We consider such possibilities extremely remote, and we find ourselves in general agreement with Marcus and Miller [14]: “Overall, we know who is pretty or handsome, and those who are attractive know it as well” [p. 334].

Limitations

Evolutionary psychology has been described by one critic as a field that “requires reducing people to our base instincts” [25]. Independent of the validity of such a critique, the present studies suggest that those who benefit from enhanced physical attractiveness, either as judged by others (Study 1) or themselves (Study 2), are more likely to favor aspects of evolutionary psychology that pertain to human mating.

Of course, based on reported demographic data, participants in our studies were not representative of the U.S. population as a whole, being younger, more liberal, and from a higher family income bracket than the typical U.S. citizen. They were, as well, only asked to respond to the account of evolutionary psychology that we provided to them. In order to ensure a concise stimulus paragraph, such an account was somewhat simplified, describing differences between female and male mating preferences that, while continuing to be supported by current research [26], could more properly be characterized in relative rather than absolute terms, with significant overlap between the sexes in terms of mating strategies [27].

Moreover, although our hypotheses were derived from theories of motivated inference, it is important to note that the present studies were concerned solely with documenting the existence of the relevant bias. Additional research could help explicate the underlying reasons for the favoring by physically attractive individuals of the specific predictions of evolutionary psychology that were explored in these studies. Indeed, although a motivated inference account would suggest that physically attractive individuals would favor a theory that privileges their ingroup [28], and thus they would be particularly attracted to aspects of the provided evolutionary account that highlighted the benefits of physical beauty for themselves and/or their anticipated mate, it is at least possible that such individuals were particularly drawn to other aspects of the theory, such as those privileging resource accumulation. Again, further research could help untangle these possibilities.

Although these studies included limitations and revealed modest effect sizes, the complementary approach of correlational and experimental designs bolsters the validity of the findings, which arguably can be considered substantial in the context of other plausible predictor variables [29]. Indeed, when individuals were presented with a definition of evolutionary psychology, including its application to mate preferences, observer-rated physical attractiveness best predicted support of the theory, in terms of the absolute value of the relevant correlation coefficient, r(84) = .31, 95% CI = [.11,.50], as compared to the next three highest contenders. These included self-esteem, r(125) = .22, 95% CI = [.04,.38] and political orientation (with, again, higher numbers = more conservative), r(125) = .21, 95% CI = [.04,.38], both assessed in the Study 2a control condition; and gender (coded as 1 = female, 2 = male), r(84) = .19 [-.03,.39], as assessed in Study 1, all of three which, interestingly, appeared to be much more aligned in terms of their absolute effect sizes.