There is behavioral ecology, which looks closely at the difference different ecologies make to behavior and other features of animals and humans. There's evolutionary individual psychology, there's evolutionary social psychology. In Darwin's terms, evolution couldn't exist without variation, and variation is important in behavioral genetics. And so on, and so on. There are so many instances in which evolution actually sharpens the precision, I think, with which one can find out the importance of differences. We're interested in differences as well as commonalities.