Anthony Gottlieb has written (New Yorker 9/17/12) an important critique of the increasing application of evolutionary accounts of human behavior. He writes:
Today’s biologists tend to be cautious about labeling any trait as an evolutionary adaptation—that is, one that is spread through a population because it provided a reproductive advantage. It’s a concept that is easily abused …
While his discussion of evolutionary psychology is wide ranging, I want only to summarize the methodological limitations that in his view, as well as mine, characterize the field. It doesn’t matter what your conclusions are if they are based on a limited, error-prone method.
And there are several methodological weaknesses in most current evolutionary studies of human thought and action.
1. Disentangling the separate effects of culture and biology (e.g. reproductive advantage) is perhaps the greatest difficulty faced by evolutionary psychologists. In the absence of hard evidence, say rigorous, well-controlled randomized experiments, this is a problem for most attempts to explain behavior.
2. Research in this area is of limited value when it is based almost entirely on self reports that are extremely unreliable and subject to a number of biases inherent in the laboratory study of human behavior
3. The vast majority of evolutionary psychology studies are carried out with college sophomores, taking a psychology course, where experimental participation is a course requirement.
4. These studies are also conducted almost entirely with students in Western, industrialized nations largely in the United States.
Establishing very general, universal principles of evolutionary psychology is the goal of this discipline. At the same time, the field seems to have little concern for human variation, for the enormous differences there are between individuals. American college sophomores are hardly the basis for developing such a science.
It is well known they are quite different in several respects (styles of reasoning, individual versus group perspective, etc.) from comparable groups in non-Western cultures. To formulate a set of very general principles is going to require a cross cultural program of research in which a fair number of influential variables are examined in well-controlled, multivariate designs.
While many of these limitations are understood and often acknowledged, they are often forgotten or ignored. The same is true for discussions of other areas of psychology, economics, and sociology. It is unfortunate they are so easily set aside.