ABSTRACT
We should remind ourselves that it will not do to say casually that big brains give rise to intelligence, which is obviously useful to survival. If it were this simple all creatures would have big brains. What we need to understand is why a few species of primates accelerated away from the others in terms of brain capacity about 3 million years ago. To understand this it is useful at first to examine primate intelligence. There are two popular theories at present that address the problem of why primates are vastly more intelligent than most mammals. One is that the environment of primates poses special problems in terms of the mental capacity needed to gather food; the other is that group living for primates requires considerable mental skill and agility. We will describe the reasoning behind each theory in turn and then move to examine how these theories and others can be tested.
