Question

What causes aggression?

Is aggression learned or chemical in nature?

Answer 1

Aggression is a physical and/or verbal behaviour with an intention to harm oneself, another person, or surrounding people either caused biologically or socially.

Explanation:

Biological Influences:
1) Genes. If your parents (or even your ancestors) are prone to be aggressive or passive, your trait may reflect any of them.
2) Blood chemistry
a) Most drugs (including alcohol) can contribute too aggressive behaviour by decreasing self-awareness (deindividuation factor), and decreasing the ability to accurately perceive the outcome of an aggressive act.
b) Low blood sugar levels can boost aggressiveness.
c) Males with high testosterone levels are more prone to delinquency, hard drug use, and aggressive responses when provoked.
3) Environmental
a) Pain
b) Heat
c) Crowding

Social Influences:
1) Frustration creates a motive for aggression. Fear of punishment or disapproval may cause the aggressive behavior to be displaced against some other target, or oneself. Anger arises when a person who frustrates us could have chosen to act otherwise.
2) Environmental cues can amplify aggressive behavior. EX: Children who had just played with toy guns were more likely to knock down another child's blocks than children who had been playing with non-aggressive toys.
3) Upbringing of the children (Observational Learning). EX: Children will be likely more aggressive in the future when their aggressive behaviours are ignored or tolerated by the parents, or their parents are likely to be aggressive as well. Sources may include:
a) Family
b) Subculture
c) Mass Media

*Sources: https://en.wikipedia.org/wiki/Aggression http://psychology.about.com/od/aindex/g/aggression.htm http://homepages.rpi.edu/~verwyc/oh10.htm*