Evolutionary Explanations of Human Aggression Lesson Objective: To understand how jealousy and infidelity can influence aggressive behaviour

What is evolutionary psychology? Combine ideas from evolutionary biology and neuroscience Believe that the innate brain functioning contributes to our behaviours We adapt to our environments Looking at how the human brain has evolved we can explain human behaviour (ie. Aggression)

What is evolutionary psychology? Evolutionary psychologists try to identify how aggression developed in the first place Knowing the roots of aggression, we can understand about aggression in humans today IS THIS USEFUL?

DEFINITIONS: match up! Ethology Benign aggression Malignant aggression Ritualised aggression Appeasement tactic Behaviour that stops the aggression, avoids injury. The animal admits defeat and Shows submissive behaviour. Showing of aggression for asserting power and maintaining status Study of animal behaviour Similar to animal aggression, it involves an impulsive act if threatened An evil act which is not instinctive

Aggressive behaviour by ANIMALS WHY WOULD AN ANIMAL HAVE TO FIGHT?

Aggressive behaviour by ANIMALS Animals don’t try to kill other animals It is their aim to get their attacker to back down LORENZ (1966) – ethologist Four main drives: Fear Reproduction Hunger Aggression Functions of Aggression Only the fittest/strongest are selected as mates Ensure survival of the young (protecting offspring) Animals could have their own territories

Displays of animal aggression Ritualised aggression – in social life and ‘tribe’ Morris (1990) animals show restraint, they often use appeasement tactics

Aggressive behaviour by HUMANS Fromm (1973) states that human aggression comes in two forms: Benign aggression (parent defending child) Malignant aggression (gangs, genocide) LORENZ MISSES OUT 3 BASIC THINGS Nelson (1974) The process of learning Structural causes Psychological causes

Aggressive behaviour by HUMANS Infidelity and Jealousy Daly and Wilson (1988) men have evolved strategies to deter their female partners to commit adultery From vigilance to violence Fuelled by jealousy Evolved to deal with the treat of PATERNAL UNCERTAINTY

Infidelity and Jealousy Cuckoldry and Sexual Jealousy Men can never be certain that they are a father Always at risk of cuckoldry Might have to invest resources in children that are not theirs Adaptive function of sexual jealousy to stop sexual infidelity

Infidelity and Jealousy Male retention and Violence Buss (1988) men have strategies to keep a mate How??!

Infidelity and Jealousy Male retention and Violence Buss (1988) men have strategies to keep a mate Direct Guarding Negative Inducements

Infidelity and Jealousy UX……………… (wife-killing) Guard against infidelity either by BENEFITS or COSTS Not all men can provide benefits, so many result to violence (costs) Daly and Wilson (1988) death from physical violence may be an unintended outcome of an evolutionary adaptation that was designed for control

evolutionary instinct? Case Study Killers? Victims of their evolutionary instinct? Pipat Lueprasitkul Stephen Grant www.foxnews.com/story/0,2933,256840,00.html

The Evolution of Homicide Lack of Resources Killers – large proportion are: Unemployed Unmarried Lack an ability to attract long-term mates Is this being used as excuse? What are the causes of murder?

The Evolution of Homicide Loss of Status Killers – defending their status in a large peer group Loss of status is bad for survival and reproduction Mechanisms continue to operate, triggered by events that would triggered them in our ancestral past

The Evolution of Homicide Sexual Jealousy Same-sex killings Male-male homicide can be the result of ‘love triangles’

AO2 GENDER BIAS – focus on men BLAME? Apply to real-life

AO3 Correlation Case Studies Surveys (self-report) = social desirability Evolutionary Perspective