Aggression: Intentional behavior aiming at causing physical or psychological harm

Hostile Aggression: Aggression from feeling of anger, aimed at inflicting pain (e.g. most murders, linebacker tackling a blocker because they’re angry)
Instrumental Aggression: Aggression as a means to a goal, not for causing pain (e.g. terrorist acts, violent acts of retribution or sexual coercion, linebacker tackling a blocker to catch a ball)

Reason for Aggression

Sigmund Freud: Humans are born with instinct toward life (Libido) and death or aggression (Thanatos)

Build up and must be released, or else it will cause illness
Problem - Explaining by naming: It’s explaining aggression by naming it, doesn’t really explain why the instinct exist
Problem 2: Aggressive instinct isn’t innate (cats don’t attack rats when raised together) Human aggression is too variable to be identified as innate. (e.g. cultural variation)
Problem: Even though aggression has survival value, all organisms have ways to inhibit aggression

Genetics influence brain’s sensitivity to aggressive cues. (evidence: guard dogs can be selectively breed for aggression)

Genes interact with the environment: (combination of gene that alters neurotransmitter balance and childhood maltreatment)

Amygdala: Area in the brain associated with aggressive behavior

Is flexible (e.g. stimulating amygdala in male monkeys, they only attack weaker ones)

Prefrontal Cortex: Prefrontal cortex is 15% smaller for men with antisocial personality disorder.

Neurotransmitters: