The left hemisphere of the brain is one of the two halves of the brain that have been functionally and structurally differentiated by researchers. It is primarily associated with logic and analytical thinking, verbal understanding and expression, and executive functions such as memory, problem solving and speech. The left hemisphere is also responsible for recognizing and comprehending language, processing visual stimulation and recognizing facial expressions. In addition, the left hemisphere is responsible for mathematical abilities, understanding abstract concepts and retrieving facts. In contrast, the right hemisphere is primarily responsible for visuospatial functions, including navigation and facial recognition, abstract reasoning, and emotion.

See also: evolutionary psychology, cognitive science, emergence, origin of life, evolution