Evolutionary psychology

Evolutionary psychology is the study of how the situation in which a population has evolved has shaped their psychological traits through natural selection. Evolutionary psychology serves to investigate the evolutionary origin of the various specific character traits, behavioral instincts, and preferences. The study of evolutionary psychology may apply to any conscious animal, but most study of evolutionary psychology is focused on humans. The study of evolutionary psychology especially focuses on the psychological traits that have a non-obvious origin.

There are 2 different aspects of human evolutionary psychology, which are:
 * 1) the study of why all humans have a particular psychological trait
 * 2) the study of why some humans have a particular psychological trait while others have a different psychological trait