Saturday, June 27, 2009

The Great, Profound, and Valuable Works of Evolutionary Psychology

A few weeks ago I was having an email discussion about evolutionary psychology with Gad Saad. Readers may recall an earlier posting about Gad's work on the correlation between the length of one's fingers and the kinds of things one likes to buy in a store [Psychology and Finger Length].

One of my criticisms of evolutionary psychology is that its proponents don't usually seem to have a good handle on modern evolutionary biology. Gad argues that, while this may be true for some evolutionary psychologists, it's not a widespread problem. He, for example, considers himself to be very knowledgeable about evolution. His undergraduate degree is in Mathematics and Computer Science. He then went on to obtain an MBA, an MS in Management, and finally a PhD in Marketing [Gad Saad].

He is currently an Associate Professor in the Marketing Department at Concordia University, Montreal, Canada. But over the years he has learned a great deal about evolution and in 2008 he was appointed to the "Concordia University Research Chair in Evolutionary Behavioral Sciences and Darwinian Consumption." Gad explained to me that this appointment was recommended by several experienced evolutionary biologists.

We weren't making much progress in our email discussions. It seemed that we had been reading different accounts of evolutionary theory because we couldn't agree on some basic concepts. Nevertheless, Gad advanced a number of vigorous defenses of evolutionary psychology including the following point that I reproduce from our email exchange with his permission. (Actually, he gave me permission to post his list of "great, profound, and valuable works" but not the actual paragraph where he made the claim. I posted the actual claim because it differs from what Gad said in the comment to my earlier posting.)
You are indeed correct that evolutionary psychology has at times succumbed to the allure of just-so storytelling. That said, it is unfair (and frankly dishonest of you) to place all evolutionary behavioral scientists under the negative umbrella that you repeatedly do. Evolutionary psychologists produce great, profound, and valuable works, and at times can produce weaker works with tenuous conclusions. This holds true of biochemists as well. Physicists disagree as to whether String Theory is valid or not. Should we equally view physicists as providers of shoddy and controversial work?
I was intrigued by the claim that evolutionary psychologists have produced "great, profound, and valuable works" and I asked for examples. He supplied them but around that time I got distracted by real life and didn't follow up on our email exchanges.

Now Gad has posted his list in the comments to yesterday's posting on Why Evolutionary Psychology Is False.

I think it deserves wider coverage so here, without comment, is Gad Saad's list of the great, profound, and valuable works of evolutionary psychology. This is the best of the best by one of the leading experts in the field. I think we can get a good sense of the overall quality of the discipline by examining the list.
  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.
  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.
  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.


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