aggression

Meaning: Aggression is behavior intended to harm another individual, whether physical or verbal. Hostile (reactive) aggression is driven by anger, while instrumental aggression is a means to a goal, such as taking money. Biological factors include the amygdala, which promotes aggressive responses, the prefrontal cortex, which helps restrain them, higher testosterone, and lower serotonin activity. Psychological accounts include social learning and the frustration-aggression hypothesis, in which frustration raises the likelihood of aggression.

On the MCAT: A passage may describe Bandura's Bobo doll experiment, where children who watched an adult hit the doll tended to imitate it. The explanation is observational learning (modeling). Other items ask which brain change or neurotransmitter level predicts more aggression, or whether a scenario is hostile or instrumental.

Common confusion: Intent to harm defines aggression, so accidental harm or simple assertiveness does not count. Students also treat aggression as either innate or learned, but the exam accepts both biological and learned contributions. Lower serotonin activity, not higher, is the usual association with aggression.