A comparative perspective on lateral biases and social behavior.

Cerebral lateralization and associated motor behaviors were historically thought to be characteristics unique to humans. Today, it is clear that these features are present and visible in other animal species. These shared attributes of brain and behavior suggest inheritance from a distant common ancestor. Population-level motor biases are likely to reflect an early evolutionary division of primary survival functions of the brain's left and right hemispheres. In modern humans, these features may provide a foundational platform for the development of higher cognitive functions, inextricably cementing the ties between the evolution and development of cognition. This chapter focuses on the links between a vertebrate-wide right hemisphere dominance for perceiving and producing social signals, left side motor biases (inclusive of visual field preferences), and the evolution and development of cognition in modern humans.