A defence of evolutionary psychology

The letter by Rose & Lucas (2001), with its unconventional structure (having been written by Lucas with a lengthy quote from Rose but then signed by Rose as the first author), repeats the misleading arguments that can be found in abundance in Rose & Rose (2000). Professor Rose claims to welcome a hypothesis-driven scientific discipline of evolutionary psychology but laments what is, according to him, the present state of the discipline that is no more than an “untestable bunch of anecdotes based upon a priori ideological convictions”. He is also indignant at my suggestion that he is in effect in the camp that holds that the human mind is a blank slate.

As to the first point, his position is far from credible. He contends that the hypothesis that the human psychological make-up was formed during the Pleistocene is incorrect and that this is somehow fatal to the whole enterprise of evolutionary psychology. In fact, the contention that the human psyche or mind formed primarily during the Pleistocene is no more than an empirical question that requires testing through evidence. If evidence from various sources shows this to be incorrect, then this idea should certainly be modified or abandoned but, whichever way this question will be settled, it will not herald the end of evolutionary psychology. The core idea of evolutionary psychology is the assumption that the human mind has a species-specific architecture that contains a degree of variability and plasticity depending on environmental influences, but (and this is the most important point) it is not infinitely malleable, as the standard social science model would have us believe. It is rather surprising that Rose, in the same breath, claims to reject the tabula rasa view of the mind and rejects any hypotheses that suggest it may have any definable architecture on the grounds that conceding this is genetically deterministic. If the mind is not a blank slate, then it should have some architecture. For a Darwinian, this architecture is partly (not wholly) determined by our genetic heritage which, in turn, has been shaped by aeons of selection in a particular type of environment (whatever that may be). We can argue about what this architecture may look like through proposing hypotheses and empirically testing them.

Rose chooses to ignore the abundant evidence of the vibrancy of evolutionary psychology where hypotheses and theories are continually tested, debated, modified and discarded. It is a fast-moving field where one can quickly be overtaken by new ideas and new evidence. Take, for example, the waist-to-hip ratio that Rose has cited. The suggestion was made in the early 1990s that there may be a universally attractive human female shape that signals maximum reproductive value. This triggered transcultural comparison studies by evolutionary psychologists that showed that there were exceptions to this (see for example Marlowe & Westman, 2001). It is likely that the hypothesis will now be modified to incorporate the effect of ecological influences. There are many other examples of such vigorous hypothesis-testing such as in the area of human sexuality where major theoretical modifications have taken place based upon empirical findings (see Buss, 2000).