Aggression: Key Terms Flashcards
The Limbic System
an area of the brain that helps to coordinate behaviours that satisfy motivational and emotional urges
2 Key Structures in Limbic System Associated with Aggression
1) amygdala
2) hippocampus
Role of Amydala in Aggression
- responsible for quickly evaluating emotional importance of sensory info + prompting appropriate response
- if certain areas of amygdala are stimulated electrically, an animal responds with aggression
Role of Hippocampus in Aggression
- involved in formation of long term memories
- allows an animal to compare conditions of current threat with similar past experiences
- impaired hippocampul function prevents nervous system from putting things into relevant + meaningful context so may cause amygdala to respond inappropriately, resulting in aggressive behaviour
Role of Testosterone in Aggression
- increased testosterone levels is related to increased amygdala reactivity which leads to aggressive behaviour
Role of MAOA in Aggression
- regulates metabolism of serotonin in the brain, mops up neurotransmitters after nerve impulse
- does this by breaking down neurotransmitter into consituent chemicals to be recycled or excreted
Difference between MAOA-H and MAOA-L
- MAOA-H is associated with high levels of MAOA and MAOA-L is associated with low levels
- those with MAOA-L variant more likely to grow up to exhibit anti-social behaviour but only if they had been maltreated as a child
- MAOA-L is more frequent in populations with a history of warfare
Fixed Action Pattern (FAP)
a repetoire of stereotyped behaviours which occur in specific conditions (ie in response to specific triggers) and which don’t require learning
6 Characteristics of Fixed Action Patterns
1) stereotyped - the behaviour always occurs in the same way
2) universal - the behaviour is the same in all conspecifics
3) independent of individual experience - the behaviour is innate, with no learning involved
4) ballistic - once triggered, the FAP can’t be changed or stopped
5) specific triggers - each FAP has a specific trigger (sign stimulus)
6) single purpose - the behaviour only occurs in a specific situation
Innate Releasing Mechanism (IRM)
a neural network that, when stimulated by the presence of a sign stimulus, communicates with motor control circuits to activate the fixed action pattern associated with that sign stimulus
Ritualistic Aggression
aggressive behaviour that involves threat displays instead of fighting
Hydraulic Model
- each fixed action pattern (FAP) has a reservoir of ‘action-specific energy’ (ASE) that builds up over time
- the appropriate sign stimulus causes the innate releasing mechanism (IRM) to release this energy and the animal then performs the FAP
- after performing the FAP, the reservoir of ASE is empty and the behaviour can’t be repeated until the ASE has built up again
How is Ritualistic Aggression Adaptive?
- high levels of aggression in males leads to dominance and more access to females
- this is evolutionary as genes are passed to the next generation
- submission rituals are advantageous because animals survive and not all are killed so the species doesn’t die out and can contribute to survival of group
Intra-species Threat Displays and How They Are Adaptive
- threat displays towards animals of same species
- makes physical aggression less likely to occur so that the existence of the species isn’t threatened
Inter-species Threat Displays and How They Are Adaptive
- threat displays towards animals of other species
- other animals can assess their relative strength before conflict
Sexual Jealousy
- motivator of aggressive behaviour in males
- because of paternal uncertainty and risk of cuckoldry
- any investment in offspring that isn’t there own is waste of resources and contributes to survival of rival’s genes and leaves father with fewer resources to invest in his own offspring
- men who avoided cuckoldry were more reproductively successful so psychological mechanisms have evolved in men to prevent cuckoldry occurring
Mate Retention Strategies
- direct guarding: male vigilance over a partners behaviour
- negative inducement: threats of dire consequences for infidelity
Dollard et al Frustration-Aggression Hypothesis
- frustration always leads to aggression
- if aggression is present there must have been frustration
- frustration leads to an aggressive drive which leads to aggressive behaviour
- aggressive urges can be relieved throught the production of aggressive behaviour which therefore has a cathartic effect
- views agression as a biological drive
- hydraulic theory of aggression
Displaced Aggression: The “Kicking the Dog” Effect
- the f-a hypothesis states that when people are frustrated they experience a drive to be aggressive towards the object of their frustration
- however this may be innapropriate, or the object of the aggression may not be available or may be an abstract concept so the aggression may then be inhibited
- dollard et al propose that the aggression may be displaced onto someone or something else
- aggression against a scapegoat leads to catharsis
Justified and Unjustified Frustration
- pastore (1952) refined the f-a hypothesis in terms of justified and unjustified frustration
- pastore showed that people express lower levels of anger when the frustration is justified
Berkowitz (1989): Revised F-A Hypothesis
- proposed that frustration is one of many kinds of unpleasant experiences that can lead to aggression
- unpleasant experiences lead to negative affect (ie negative uncomfortable feelings) which leads to aggressive behaviour
- it’s the negative affect not the frustration which trigger the aggression
- he distinguished between anticipated and unanticipated interference
- predicts that unanticipated interference is experienced as more unpleasant and is therefore more likely to lead to aggressive behaviour
Twin & Adoption Studies for Genetic Explanation
- the concordance rate for MZ twins is greater than the concordance rate for DZ twins for aggression meaning that this trait is at least partially inherited but there also must be environmental influences
- identity confusion (when MZ twins are so similar they are treated the same) could be why MZ twins are more similar than DZ twins instead of genetic factors
- adoption studies get rid of identity confusion
Key Study: Tinbergen (1951)
Procedure: presented sticklebacks with series of wooden models of different shapes and with or without red spot, highly territorial during mating season when they develop red spot on underbelly
Findings: regardless of shape if model had red spot the stickleback would show aggression, if no red spot no aggression even if model looked like stickleback, FAPs unchanging and ran its course to completion each time
Conclusion: FAPs onlu occur in specific conditions
Sexual Competition
- ancestral males seeking access to females would have had to compete with other males
- one way of eliminating competition would be through physical aggression
- those individuals who were successful against competitors would be more successful in acquiring mates and would be more successful in passing on genes