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Ingrid L.Stefanovic

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Lecture 21: Aggression
Lecture Overview
x Aggression
x Approaches to Aggression
x Television & Violence
Intentional behaviour aimed at causing physical or psychological pain
x Two dimensions of classification:
o Type of pain
o Goal of pain
Type of Pain
x Physical Aggression
o Aggression inflicting physical pain
x Verbal or Relational Aggression
o Saying or doing psychologically hurtful things
Goal of Aggression
x We make a distinction between hostile and instrumental aggression
o What is the goal of the aggression?
Hostile Aggression
x Aggressive behaviour that:
o Stems from feelings of anger
o Has the goal of inflicting pain
Instrumental Aggression
x Aggressive behaviour that:
o Inflicts pain
o The pain is a middle step toward another goal (the outcome goal is not pain, pain
is used to achieve the outcome goal)
Big Picture Questions
1. Is aggression:
x A .A positive thing
x B. A negative thing
x C.I t depends
2. Is aggression:
x A. Societally produced (derived from culture)
x B. A natural thing (derived from biology)
x C. An interaction of the two
Approaches to Aggression
x Think about a time when you hurt someone else
x Why did you do it?
Why We Hurt: Typical Answers
o Genetic Predisposition
o Chemical Influence
o Frustration-Aggression Theory
o Social Learning Theory
Genetic Predisposition
x Theory and early work
x Neural Structure:
o Amygdala
o Pre Frontal Cortex
x Hormones and Neurotransmitters:
o Testosterone
o Seratonin
Genetic Predisposition?
x Basic Theoretical Premise:
o Aggression is adaptive and has survival value
x Earliest evidence:
o Animals can be bred for aggression (e.g., Rottweilers have been selected over
time for aggressive traits)
o Twin studies find high heritability for aggression
High similarity in aggression for identical twins relative to fraternal twins
± this suggests a genetic component to aggression
x Stimulating amygdala can lead to aggression
x Depends on context: (good evidence of an interaction between biology and social
o Sometimes leads to withdrawal/fear
If one is in a confrontation where they are likely to win, and the amygdala
is stimulated, the person will be aggressive. However, when in a context
were the person is likely not to win, stimulation of the amygdala produces
a withdrawal response
o Relative social status matters
When the amygdala is stimulated, and rats are in the presence of higher
status rats, they retreat in fear. When the amygdala is stimulated and rats
are in the presence of lower status rats, they approach and aggress. Social
status makes a big difference in response.
Pre Frontal Cortex
x PFC may be the regulator of aggressive impulses
o Generally involved in planning & behavioural regulation
o The more activity in the PFC, the more able one is to regulate their aggressive
behaviour, even if the amygdala is activated
x Relation of PFC and Aggression:
o Murderers have less PFC activity than normal controls
o PFC becomes activated when contemplating an aggressive act
going to do it
x The steroid hormone testosterone may increase aggression
x Greater exposure to testosterone in womb (related to finger length) linked to aggression
x But:
o Injecting testosterone does not increase aggression
o Testosterone-aggression is weak/small effect, r = .14