section_path: Theories of motivation/Evolutionary
section_name: Evolutionary
paragraph_text: Evolutionary
  
  Several theories concern the evolutionary origins of warfare. There are two main schools: One sees organized warfare as emerging in or after the Mesolithic as a result of complex social organization and greater population density and competition over resources; the other sees human warfare as a more ancient practice derived from common animal tendencies, such as territoriality and sexual competition.
  
  The latter school argues that since warlike behavior patterns are found in many primate species such as chimpanzees, as well as in many ant species, group conflict may be a general feature of animal social behavior. Some proponents of the idea argue that war, while innate, has been intensified greatly by developments of technology and social organization such as weaponry and states.
  
  Psychologist and linguist Steven Pinker argued that war-related behaviors may have been naturally selected in the ancestral environment due to the benefits of victory. He also argued that in order to have credible deterrence against other groups (as well as on an individual level), it was important to have a reputation for retaliation, causing humans to develop instincts for revenge as well as for protecting a group's (or an individual's) reputation (" honor ").
  
  Crofoot and Wrangham have argued that warfare, if defined as group interactions in which "coalitions attempt to aggressively dominate or kill members of other groups", is a characteristic of most human societies. Those in which it has been lacking "tend to be societies that were politically dominated by their neighbors".
  
  Ashley Montagu strongly denied universalistic instinctual arguments, arguing that social factors and childhood socialization are important in determining the nature and presence of warfare. Thus, he argues, warfare is not a universal human occurrence and appears to have been a historical invention, associated with certain types of human societies. Montagu's argument is supported by ethnographic research conducted in societies where the concept of aggression seems to be entirely absent, e.g. the Chewong and Semai of the Malay peninsula. Bobbi S. Low has observed correlation between warfare and education, noting societies where warfare is commonplace encourage their children to be more aggressive.