It was (and is) common to think that other animals are ruled by "instinct" whereas humans lost their instincts and ruled by "reason," and that this is why we are so much more flexibly intelligent than other animals. William James, in his book Principles of psychology, 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."
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 central 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 problem we are bad at, like learning math or playing chess, than ones we are good at. But 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 heterogeneous 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.
William James believed that man is more flexibly intelligent than other animals because man is more ______.

A. adaptive
B. reasonable
C. instinctive
D. sophisticated