I've recently been reading Why Beautiful People Have More Daughters, by Alan S. Miller and Satoshi Kanazawa. It is basically the evolutionary psychology stance on a number of very interesting and controversial questions. Evolutionary psychology differs from the social science standpoint of tabula rasa, or the idea that we are a blank slate at birth waiting for our environment to shape us. Evolutionary psychology sees human nature as greatly hardwired by evolution, and only slightly modified by environmental factors.
Here is an article adapted from the book from Psychology Today. It outlines "Ten Politically Incorrect Truths About Human Nature" including: "Why most suicide bombers are Muslim, beautiful people have more daughters, humans are naturally polygamous, sexual harassment isn't sexist, and blonds are more attractive."
Interesting stuff. Just makes me realize even more that we really have very little clue why we do what we do. Science has so many different standpoints. Who's to say what's accurate? Who's to say what I or you are more influenced by, your evolution or your environment? How can we possibly ever know for certain which of the two has influenced which life choices? How can we ever really know, as I like to say, "what's driving the bus"? It all makes my head spin. And makes me want to cower in a dark corner and never read again. Sigh.