Evolution of the Prefrontal Cortex in Non-human Primates

The primate prefrontal (PF) cortex evolved in phases. The first PF granular areas emerged as early primates and their closest ancestors adapted to an arboreal life. These areas improved the use of vision to search for foods and decide whether they were edible. Another phase of PF evolution occurred in anthropoids as they adapted to a diurnal life. They increased in body size and foraged over large distances, using foveal vision to search for resources. This exposed them to new competitors and encouraged social grouping, the advantage being that there are many eyes on the lookout for danger. The brain expanded in relation to the size of the body (encephalization) and the cortex expanded as a proportion of the brain (corticalization). At the same time, new PF areas emerged.