EVOLUTIONARY PSYCHOLOGY YIELDS FASCINATING AND UNEXPECTED FINDINGS
By Gad Saad, Ph.D.
Psychology Today
June 29, 2009

Original Link

I recently had an email exchange with a biochemist about the ability of evolutionary psychology (EP) to generate important and valid scientific knowledge. During our e-chats, he challenged me to provide him with findings that have ever been uncovered via the EP framework that were "great, profound, and valuable."  At first, I responded that this was a silly challenge as I found it hard to believe that even a strident anti-EPer such as himself could genuinely believe that of the endless scientific papers that have been published within the framework, not a SINGLE one possessed any value or merit (apparently he could not think of any). The biochemist replied that my unwillingness to provide him with any examples was implicitly supportive of his very low opinion of EP. I could not allow such a throwing down of the gauntlet to go unchallenged, so I sent him the following list of 15 findings, which I subsequently posted as a comment on his blog. This is not meant to be the definitive list of key EP findings, as there are endless other ones that could have been included herewith.  Rather, it is meant to capture the wide range of topics that are addressed by EPers.

(1) Women alter their preferences for the facial features of men as a function of where they are in their menstrual cycles. When maximally fertile, they prefer men possessing markers of high testosterone.

(2) Babies display an immediate instinctual preference for symmetric faces (at an age that precedes the capacity for socialization).

(3) Children who suffer from congenital adrenal hyperplasia display a reversal in their toy preferences. Furthermore, using inter-species comparisons, vervet monkeys display the same sex-specific patterns of play/toy preferences as human infants. This suggests that contrary to the argument made by social constructivists, play has an evolved biological basis.

(4) Individuals who score high on an empathy scale are more likely to succumb to the contagion effects of yawning. This is indicative that this particular contagion might be linked to mimicry and/or Theory of Mind.

(5) How provocatively a woman dresses is highly correlated to her menstrual cycle (a form of sexual signaling found across countless Mammalian species).

(6) Culinary traditions are adaptations to local niches. For example, the extent to which a culture utilizes meat versus vegetables, spices, or salt is a cultural adaptation (this is what behavioral ecologists study).

(7) Maternal grandmothers and paternal grandfathers invest the most and the least respectively in their grandchildren. Whereas all four grandparents have a genetic relatedness coefficient of 0.25 with their grandchildren, they do not all carry the same level of "parental uncertainty." In the case of maternal grandmothers, there is no uncertainty whereas in the case of the paternal grandfather, there are two sources of uncertainty. This last fact drives the differential pattern of investment in the grandchildren.

(8) Good male dancers are symmetric (paper published in Nature). One would expect that some behavioral traits might correlate with phenotypic quality as honest signals of an individual's desirability on the mating market. I discussed this exact finding in an earlier post here.

(9) Self-preference for perfumes is linked to one's immunogenetic profile (Major Histocompatibility Complex).

(10) When a baby is born, most family members (especially those of the mother) are likely to state that the baby looks like the father. This phenomenon is found in countless cultures despite the fact that it is objectively impossible to make such a claim of resemblance. The reason for this universally found cultural tradition lies in the need to assuage the fears of paternity uncertainty. I discussed this phenomenon in one of my earlier posts here.

(11) Environmental stressors (e.g., father absence) and the onset of menarche (first menses) have been shown to be highly linked. In numerous species, the likelihood of a female becoming reproductively viable is affected by environmental contingencies.

(12) Women are less receptive to mandatory hospital DNA paternity testing (for obvious reasons). In other words, their willingness to adopt a new product/service is fully driven by an evolutionary-based calculus.

(13) Women can smell the most symmetric men. In other words, women have the capacity to identify men who possess the best phenotypic quality simply via their nose. This is what I have referred to as sensorial convergence.

(14) Using fMRI, the exposure to ecologically relevant stimuli (e.g., beautiful faces) yields distinct neural activation patterns in men and women.

(15) In choosing a mate, humans tend to prefer the smell of others that are maximally dissimilar to them along the MHC. This ensures that offspring possess a greater "defensive coverage" in terms of their immunological system.

The biochemist (and some of his supporters) simply dismissed all of the latter findings without providing any specific criticisms. In the same way that religious people require no evidence to believe in God, many anti-EPers argue that EP is rubbish on faith.  

Note that none of the latter findings are congruent with genetic determinism; none condone or justify rape or male infidelity; none consist of fanciful just-so story telling; none posit unfalsifiable hypotheses.

Scientific debate is healthy. This is why I am always excited by the prospect of engaging in such an endeavor, be it with colleagues and/or the public at large. However, I am afraid that the great majority of critics of evolutionary psychology (in the greater sense of the term) have a caricatured knowledge of the field consisting of discredited concerns that have been addressed by evolutionists for at least three decades.

You can check out my book, The Evolutionary Bases of Consumption, for endless other EP findings that might have made it onto such a list.

I am hoping that this post might trigger an Archimedean epiphany in some anti-EPers although I suspect that no information could ever alter their staunchly held negative opinions. Worth a try!