Face Processing as a Brain Adaptation at Multiple Timescales

Abstract

I consider face processing as the brain's adaptive response to phylogenetic, ontogenetic, and task-specific factors. Focusing on wide-ranging evidence from both my own laboratory and others, evidence for a primitive “quick and dirty” route for face processing that exists prior to postnatal experience is reviewed. Next, I trace the emergence of cortical specialization for face processing influenced by individual developmental experience (ontogenetic adaptation) and suggest that this ontogenetic adaptation is also heavily constrained by the phylogenetic system. Finally, I turn to recent evidence on task-specific modulation of activity in the core face network that illustrates brain adaptation at a finer timescale than that for the other systems. Current evidence indicates that task-specific modulation of the cortical face network does not emerge until the teenage years. As previously proposed for other components of cognition, I propose that these systems are complementary to each other, each compensating for the others' weaknesses. Different face-related systems are adapted to respond to survival pressures at different timescales, from millennia, to months, to microseconds.