"I suspect that unpredictability in behavior is not the first thought that comes to mind when people hear the terms "intelligence" or "cognitive ability," but variability may in fact be an important component of what we mean by those terms. And Wills's notion of a positive feedback loop helps to emphasize that the selection pressures operating in evolution very much include those resulting from other organisms. A positive feedback loop also provides a satisfying and perhaps generally useful explanation for otherwise puzzling directional trends in evolution.
"So are larger brains actually 'better'? If Wills is right, the answer depends to a significant extent on whether or not there are other, larger brains around; in this case, increasing brain size is part of an evolutionary experiment whose future outcome is uncertain, as true of all evolutionary processes. On the other hand, if Wills is right, we (and some other animals) can all count on not becoming bored--and, perhaps, on becoming steadily wiser or, at least, steadily less wrong).