Aggression
Some scholars believe that behaviors like aggression may be partially learned by watching and imitating people's behavior, while other researchers have concluded that the media may have some small effects on aggression. There is also research questioning this view. For instance, a long-term outcome study of youth found no long-term relationship between playing violent video games and youth violence or bullying. One study suggested there is a smaller effect of violent video games on aggression than has been found with television violence on aggression. This effect is positively associated with type of game violence and negatively associated to time spent playing the games. The author concluded that insufficient evidence exists to link video game violence with aggression. However, another study suggested links to aggressive behavior.
Primate
Both humans and nonhuman primates, such as chimpanzees, exhibit proactive aggression, a type of preplanned aggression with a reward. This aggression is expressed between neighboring groups. Proactive aggression ultimately increases the fitness of the community as a whole as the size of the community increases. Unlike proactive aggression, reactive aggression is low in humans but high in chimpanzees. Reactive aggression is a result of anger in order to cease a stressful stimulus. Low reactive aggression in humans can be attributed to tolerance and cooperation. Wrangham found “evolution of within-group tolerance, such as individual selection for cooperative breeding, group selection for parochial altruism, and cultural group selection for prosocial norms”. Ranking in nonhuman primates stems from the most aggressive male, while nomadic hunter-gatherers are respected for their prestige and ability to form alliances and negotiations. Boehm proposed the “execution hypothesis”, or the approval by the community of killing group members who violate the norm of the group or are deemed a bully. Hunter-gatherers who attempted to utilize aggression were viewed as a threat and removed from the group. The removal of community threats can be likened to modern capital punishment, more specifically the death penalty.