Corticalization and composition

Abstract

Abstract In modern primates, the cerebral cortex dwarfs the remainder of the brain: a dominance that developed in phases, mostly in Eocene crown primates, Miocene anthropoids, and Pleistocene hominins. In each case, a larger cortex evolved at a different time than the group’s characteristic skeletal traits, which points to different driving forces for bodies and brains. Notably, cortical expansion in Miocene hominoids occurred while they still closely resembled cercopithecoids, their sister group. The cortex also changed in composition. An extensive suite of primate- and anthropoid-specific areas emerged, many of which improved the efficiency of long-range foraging journeys. In Miocene monkeys and hominoids, faster forms of locomotion evolved in concert with a larger cortex. Later, in Pleistocene hominins, the enlargement of primate-specific cortical areas, along with the hippocampus, supported uniquely human cognitive capacities, including a prodigious accumulation of semantic generalizations and a limitless capacity to imagine the future and the past.