Participating in aggression simply makes us more, not less, aggressive. The involvement in crime usually rises in the early teens to mid teens which happen at the same time as testosterone levels rise.
We might normally notice the presence of a police officer or other people around us, which would remind us that being aggressive is not appropriate, but when we are drunk we are less likely to be so aware.
Birth complications Birth complications have been repeatedly found to be associated with later increased aggressive behavior in childhood Cocchi et al. Furthermore, aggression can be used to increase an individual's dominance in their social environment.
The relationship is not perfect, and it does not hold for everyone, but it is clear. Another evolutionary theory explaining gender differences in aggression is the Male Warrior hypothesiswhich explains that males have psychologically evolved for intergroup aggression in order to gain access to mates, resources, territory and status.
Children's competitive peer aggression during reward and punishment.
The pattern of male and female aggression is argued to be consistent with evolved sexually-selected behavioral differences,  while alternative or complimentary views emphasize conventional social roles stemming from physical evolved differences.
In this context, aggression is important to nursing in a number of ways.
In addition to helping us experience fear, the amygdala also helps us learn from situations that create fear. DHEA levels also have been studied in humans and may play a role in human aggression.
The amygdala is activated in response to positive outcomes but also to negative ones, and particularly to stimuli that we see as threatening and fear arousing.
Even in non-anarchic situations, survival instincts and fear can be very powerful forces, and they may be incited instantaneously.
Game theory is used to understand how such behaviors might spread by natural selection within a population, and potentially become 'Evolutionary Stable Strategies'.