Human brain evolution writ large and small.
Human evolution was marked by an extraordinary increase in total brain size relative to body size. While it is certain that increased encephalization is an important factor contributing to the origin of our species-specific cognitive abilities, it is difficult to disentangle which aspects of human neural structure and function are correlated by-products of brain size expansion from those that are specifically related to particular psychological specializations, such as language and enhanced "mentalizing" abilities. In this chapter, we review evidence from allometric scaling studies demonstrating that much of human neocortical organization can be understood as a product of brain enlargement. Defining extra-allometric specializations in humans is often hampered by a severe lack of comparative data from the same neuroanatomical variables across a broad range of primates. When possible, we highlight evidence for features of human neocortical architecture and function that cannot be easily explained as correlates of brain size and, hence, might be more directly associated with the evolution of uniquely human cognitive capacities.
Department of Anthropology, The George Washington University, Washington, DC, USA. sherwood@gwu.edu
Chet C
CC
Sherwood
Amy L
AL
Bauernfeind
Serena
S
Bianchi
Mary Ann
MA
Raghanti
Patrick R
PR
Hof
D000818:Animals; D005075:Biological Evolution; D049628:Body Size; D001921:Brain / Q000033:anatomy & histology* / Q000502:physiology*; D001931:Brain Mapping; D006801:Humans; D009474:Neurons / Q000166:cytology; D009929:Organ Size; D011323:Primates / Q000033:anatomy & histology / Q000502:physiology