The goal of research in evolutionary psychology is to discover and understand the design of the human mind. Evolutionary psychology is an approach to psychology, in which knowledge and principles from evolutionary biology are put to use in research on the structure of the human mind. It is not an area of study, like vision, reasoning, or social behavior. It is a way of thinking about psychology that can be applied to any topic within it. In this view, the mind is a set of information-processing machines that were designed by natural selection to solve adaptive problems faced by our hunter-gatherer ancestors. This way of thinking about the brain, mind, and behavior is changing how scientists approach old topics, and opening up new ones. This chapter is a primer on the concepts and arguments that animate it. Debauching the mind: Evolutionary psychology's past and present: In the final pages of the Origin of Species, after he had presented the theory of evolution by natural selection, Darwin made a bold prediction: "In the distant future I see open fields for far more important researches. Psychology will be based on a new foundation, that of the necessary acquirement of each mental power and capacity by gradation." Thirty years later, William James tried to do just that in his seminal book, Principles of Psychology, one of the founding works of experimental psychology (James, 1890). In Principles, James talked a lot of "instincts". This term was used to refer (roughly) to specialized neural circuits that are common to every member of a species and are the product of that species' evolutionary history. Taken together, such circuits constitute (in our own species) what one can think of as "human nature". It was (and is) common to think that other animals are ruled by "instinct" whereas humans lost their instincts and are ruled by "reason", and that this is why we are so much more flexibly intelligent than other animals. William James took the opposite view. He argued that human behavior is more flexibly intelligent than that of other animals because we have more instincts than they do, not fewer. We tend to be blind to the existence of these instincts, however, precisely because they work so well -- because they process information so effortlessly and automatically. They structure our thought so powerfully, he argued, that it can be difficult to imagine how things could be otherwise. As a result, we take "normal" behavior for granted. We do not realize that "normal" behavior needs to be explained at all. This "instinct blindness" makes the study of psychology difficult. To get past this problem, James suggested that we try to make the "natural seem strange": "It takes...a mind debauched by learning to carry the process of making the natural seem strange, so far as to ask for the why of any instinctive human act. To the metaphysician alone can such questions occur as: Why do we smile, when pleased, and not scowl? Why are we unable to talk to a crowd as we talk to a single friend? Why does a particular maiden turn our wits so upside-down? The common man can only say, Of course we smile, of course our heart palpitates at the sight of the crowd, of course we love the maiden, that beautiful soul clad in that perfect form, so palpably and flagrantly made for all eternity to be loved! And so, probably, does each animal feel about the particular things it tends to do in the presence of particular objects.... To the lion it is the lioness which is made to be loved; to the bear, the she-bear. To the broody hen the notion would probably seem monstrous that there should be a creature in the world to whom a nestful of eggs was not the utterly fascinating and precious and never-to-be-too-much-sat-upon object which it is to her. Thus we may be sure that, however mysterious some animals' instincts may appear to us, our instincts will appear no less mysterious to them." (William James, 1890) In our view, William James was right about evolutionary psychology. Making the natural seem strange is unnatural -- it requires the twisted outlook seen, for example, in Gary Larson cartoons. Yet it is a pivotal part of the enterprise. Many psychologists avoid the study of natural competences, thinking that there is nothing there to be explained. As a result, social psychologists are disappointed unless they find a phenomenon "that would surprise their grandmothers", and cognitive psychologists spend more time studying how we solve problems we are bad at, like learning math or playing chess, than ones we are good at. But our natural competences -- our abilities to see, to speak, to find someone beautiful, to reciprocate a favor, to fear disease, to fall in love, to initiate an attack, to experience moral outrage, to navigate a landscape, and myriad others -- are possible only because there is a vast and heterogenous array of complex computational machinery supporting and regulating these activities. This machinery works so well that we don't even realize that it exists -- We all suffer from instinct blindness. As a result, psychologists have neglected to study some of the most interesting machinery in the human mind.
By Leda Cosmides & John Tooby, 1997
