Aggression

Neural Mechanisms: Key Concepts

Hypothalamus - Control of endocrine and hormones

Hippocampus - Formation of LTM

Amygdala - Evaluates sensory info and gives appropriate response

Decreased Serotonin - reduces self control and increase impulsive behaviours

Neural Mechanism: Evaluation

+ Pardini et al

H Correlational

+ King case study

+ Berman et al's Serotonin and aggression

H Exact role is unclear

I/D: Biological Reductionist

Amygdala study

Pardini et al

56 male ppts with varying history of violence

MRI scans at 26

Neg. Correlation between volume of amygdala and higher levels of violence

Amygdala Case Study

King (1961)

Woman’s amygdala electrically stimulated during brain surgery

Became threatening and verbally aggressive until current turned off

Serotonin Research

Berman et al (2009)

Lab based game of giving and receiving electric shocks in response to provocation

Ppts who took Paraetine (enhances Serotonin) consistently gave fewer and less intense shocks than placebo

Hormonal Mechanisms: Key Concepts

Testosterone - regulates social behaviours

Progesterone - low levels →female aggression

Hormonal Mechanisms: Evaluation

+ Simpson - hormone substraction and replacement

- Klinesmith et al - Aggressive tasks: opposite causal effect

I/D: Nature/Nurture

Hormone Substraction & Replacement Research

Simpson (2001)

Measured normal levels of aggression of mice

Castrated mice → decrease in aggression

Replacement through hormone therapy → increase of aggression

Aggressive Tasks Research

Klinesmith et al (2006)

Male students

Saliva sample taken

Take object apart and reassemble, test & write instructions

Group 1: pellet gun, Group 2: mousetrap game

Saliva sample taken again

100 x more testosterone in group 1 saliva than group 2

Progesterone Research

Ziomkiewicz et al (2012)

Negative correlation between progesterone levels and self reported aggression

Ways of Studying Genetics

Study Twins (concordance)

Studying Adopted Children

Aggression Concordance Rates

87% in MZ twins

72% in DZ twins

Adopted Children in Aggression Variance

Genetic factors account for 41% variance in aggressive behaviours

Genetic Factors: Key Concepts

Low function MAOA Gene

Breaks down excess neurotransmitters (Serotonin & dopamine)

When in low function, less broken down

Diathesis stress

Triggered by child abuse

Genetic Factors: Evaluation

+ Caspi et al (2002) - Longitudinal NZ study

+ Brunner (1993) - Extreme violence in Dutch family

I/D: Socially sensitive (Bradley Waldroup) & Determinism

Ethological Explanation: Key Concepts

Adaptive

Benefits: reduces competition for resources

Ritualistic (Lorenz) doesn’t threaten species existence

Innate Releasing Mechanism
Neural Network
Triggered by Sign Stimulus
Activated FAP

Fixed Action Pattern
Innate sequence
Cannot be altered

Stereotyped, Universal, Innate, Ballistic, Specific Triggers

Ethological Explanation: Evaluation

+ Support for FAP - Tinbergen Stickleback Fish

- Population validity
interacting influences (SLT, media etc) for humans & animal influences not relevant

+ I/D: Interactionist - nature (IRMs & FAPs) caused by need in environment (nurture)

Stickleback Fish Experiment

Tinbergen (1951)

Clay models

Sign stimulus: red underside

FAP: Aggression and attacking model

Evolutionary Explanations: Key Concepts

Increases individual survival and procreation

Anti-Cuckoldry Behaviours

Females: certain maternity, risk loss of resources & emotional infidelity
Males: uncertain paternity, worry of sexual infidelity

Mate Retention Strategies

Bullying
Females: verbal, secures partner’s fidelity & resources
Males: physical, ensures access & reduces threats and rivals

Mate Retention Strategies

Direct guarding and vigilance

Negative Inducements (Threats of consequences: financial control, violence etc)

Evolutionary Explanations: Evaluation

+ Research Support for Aggression as Mate Retention Strategy (Shackelford)
H Correlational

- Temporal validity
Not all heterosexual or desiring to be parents or to have biological children

+ Real world application for devising antibullying interventions

I/D: Socially sensitive - shouldn’t excuse domestic violence

Research Support for Aggression as Mate Retention Strategy

Shackelford (2005)

Surveyed 461 men and 560 women

Positive correlation between men using MRS and using violence

Positive correlation in women between those with jealous partners and being victims of violence

Frustration-Aggression Hypothesis Researcher

Dollard (1939)

Frustration-Aggression Hypothesis

Drive to Goal

Obstacle to Goal

Frustration

Aggression

Catharsis success or Punishment (Frustration)

Frustration-Aggression Hypothesis: Factors Affecting Likelihood and target

Motivation

Proximity

Justification

Displacement

Frustration-Aggression Hypothesis: Evaluation

+ Support for Proximity - Harris (1974) Queuing study

+ Support for justification - Pastore bus study

+ Support for Displacement - Jigsaw puzzle (Green)

I/D: Soft deterministic - actively promotes idea of choice over level & type depending on factors

Frustration Proximity Research Queuing Study

Harris (1974)

Ppts who were naturally standing in line

Deliberately cut in line either close to head or at rear

Person at front was more proximate to their goal

Reaction coded for severity of aggression

Ppts displayed more aggression when closer to goal

Frustration Justification Bus Study

Pastore

Asked how they’d respoind to various hypothetical

Said they’d not be angry if bus not stopping seemed reasonable

Frustration Displacement Jigsaw puzzle

Green (1968)

Male uni students

4 groups: Solvable, impossible to solve, ran out of time as confederate interferes, insulted by confederate

Given opportunity to give electric shocks to confederate

All groups gave more intense than control (solvable)