I agree with Frans de Waal who suggests that the troubles in evolutionary psychology (EP) stem from a lack of understanding of evolutionary theory in general, which is hardly taught in U.S. schools (thanks to the religious wrong). Though the goal of EP is admirable – “to provide an evolutionary account of human behavior” – the approaches tend to ignore some important evolutionary aspects. De Waal identifies several mistakes made within EP: (1) Assuming that anything genetically influenced must serve a purpose; (2) investigating single traits out of context; (3) ignoring the norm/focusing on rare behavior; (4) ignoring evidence from other areas, primatology and neuroscience in particular. Based on an analysis by Jerry Coyne of Steven Pinker’s suggestions around a cognitive niche, we can add a few more problems: (5) we cannot exclude other theories through tests; and (6) the promising tests are ethically troublesome.
Let’s take a closer look at these more closely. There are many diseases that have genetic bases – for example thyroidism has at least some genetic aspects – but that does not mean that they have a purpose. In fact, evolution itself is purposeless – there is no ultimate goal. This is closely tied to problem 2: Often traits are side-effects of other characteristics, so if we only look at a single trait, we either miss the evolutionary significance or misconstrue it. De Waal gives the example of our upright posture. As anybody who has ever had back-problems knows, there is a cost to that posture. Obviously, it must have had some benefit for species survival, otherwise we would be on all fours. But it’s not a trait that by itself can be explained as evolutionary beneficial. Ignoring common behavior led evolutionary psychologists to the absurd (and offensive) claim that rape is evolutionary beneficial. Say what?!? Instead of trying to explain the minority behavior, we should look at what most people do: Not rape. Rape is also a good example for another troubling aspect of EP, which plays into problem 4: Ignoring evidence from other areas (see also this review of the book). In this case, psychology, sociology, or women’s studies could help us understand rape as something more complex as a “rape gene,” or whatever biological basis is claimed in that book.
As Anne Fausto-Sterling keeps pointing out – especially in her Bare Bones articles – we have to take a systems approach to explain human behavior (or bone structure, as Fausto-Sterling eloquently argues). Human behavior is too complex to reduce it to a gene or two. Rape could be viewed from a genetic and a power perspective, for example. Both de Waal and Jaak and Jules Panksepp call for evolutionary psychologists to look at the evidence from animal and brain sciences. EP seems rather enamored with the human animal and thus comes to conclusions that often contradict what we know from neuroscience, for example. Panksepp & Panksepp point out that much of our behavior is driven by parts of the brain that evolved long before homo was even on the scene, thus cannot be unique to humans. Similar points have been made by Elisabeth Lloyd and Marcus Feldman (the response by two evolutionary psychologists did not convince me).
Coyne points to genetic testing troubles. His arguments almost suggest that EP might be untestable, and thus unfalsifiable, because the DNA evidence is inconclusive – we cannot rule out alternate theories – and between species gene-transplant tests – promising to be more conclusive tests – might not be ethically feasible between primates and humans (though as some commentators pointed out, Coyne does not advance an argument for this).
Overall, the most troublesome critique of evolutionary psychology really comes from Fausto-Sterling, though she does not make this critique explicitly. EP ignores the interaction of lots of different factors. This will become clearer when I tackle the question “is coupling natural?”
If you know about any EP work that leverages system theories, please let me know! I really think that’s the way we need to approach the origin of human behavior… The Origins Project at ASU might be a step in that direction – it is very interdisciplinary (see also here).