AGGRESSION

Flashcards on Aggression.

What brain structures are included in the limbic system?

The amygdala and hippocampus

What is the amygdala responsible for?

Rapidly interpreting sensory information and providing an appropriate emotional response.

What happens when parts of the amygdala are electrically stimulated in hamsters?

They show signs of aggression, such as preparing to attack.

What happens when the amygdala is surgically destroyed in hamsters?

They no longer respond to stimuli that would have previously produced an aggressive response.

What is the hippocampus responsible for?

The formation of long term memories.

What happens if an animal is attacked?

A long-term memory of the encounter will be formed.

How does the pre-frontal cortex play a role in aggression?

It controls impulsive behavior, such as the urge to behave aggressively.

What type of data suggests that the amygdala is linked to aggression?

Clear cause and effect data

What did PET scans of murderers reveal?

Abnormalities in the limbic system

What did Raine et al find in serial killers?

Lowered levels of activity in the Pre-Frontal Cortex

Why is much of the research linking the limbic system and aggression correlational?

Because it is not ethically possible to determine a causal link between these two variables, especially in humans.

What do individuals with limbic system abnormalities not showing aggressive behavior suggest?

That abnormalities within the limbic system may predispose people to aggression, but not necessarily be the cause of such behaviour.

What effect does serotonin usually has on neurons firing in the brain?

A calming effect, particularly in the pre-frontal cortex.

What is the pre-frontal cortex responsible for?

Resisting the urge to behave aggressively when the limbic system is stimulated.

What happens when the pre-frontal cortex becomes flooded with serotonin during development?

The brain becomes less sensitive to the calming effect of serotonin.

What happens consequently, when stimulated, if the pre-frontal cortex is not acting as a brake?

The individual may be more likely to behave aggressively

What did researchers find in people with aggressive and impulsive behavior in regards to serotonin?

Lower levels of a waste product of serotonin in the cerebrospinal fluid

What effect does tryptophan have on monkeys behavior?

Monkeys given a diet rich in tryptophan, which increases serotonin, showed lower levels of aggression.

What actions are lower serotonin levels associated with in humans?

Assaults, self-injury and violent suicide

What affect does alcohol have on Serotonin?

High levels of alcohol reduce serotonin

What effect did the drug dexfenfluramine have on males in a study?

Taking the drug increased scores of aggression and hostility

How is aggression with hormones connected to gender?

Females do not react in the same way to decreased serotonin and points to a gender difference in neural mechanisms and aggressive behaviour

What is associated with increased physical aggression in many species?

High levels of the hormone testosterone

How are males and females different in physical aggression?

Males have higher testosterone levels than females and tend to show more physical aggression.

When are the highest levels of violence found by males?

Aged 15-25 years old which is when testosterone levels are at their highest.

What may testosterone alter, rather than making a person aggressive?

The way they react to a stimulus.

What did females who were injected with testosterone show?

A higher than usual increase in heart rate when shown photographs of angry faces.

What does testosterone reduce the amount of?

Serotonin that is available for transmission across the synapses of the nerves in the brain.

What did Albert et al (1993) point out about testosterone and aggression?

Many studies into the link between testosterone and aggression show no correlation.

What study found people with high occupational status have higher testosterone levels?

Increased assertiveness that comes from higher testosterone levels.

What is one effect testosterone has on women?

Testosterone could make women nicer rather than more aggressive, depending on the situation.

What does testosterone promote for both men and women?

Status seeking behaviour, aggression being only one type of such behaviour.

What affect does Cortisol have on levels of aggression?

Higher levels of cortisol are associated with lower levels of aggression, i.e. there is a negative correlation.

Why may higher levels of cortisol be associated lowered aggression?

High levels of cortisol increase anxiety and withdrawal

What does it mean if cortisol inhibits testosterone levels?

This may therefore result in lower aggression.

What did low levels of cortisol find in violent criminals and violent schoolchildren?

Low levels of cortisol have been found in violent criminals and violent schoolchildren.

What does the Dual Hormone Hypothesis suggest?

Both hormones interact together to produce aggression, that it is neither hormone acting alone.

What happens when high levels of cortisol inhibit?

Testosterone, when levels are low, testosterone’s effect is not inhibited, and aggression is exhibited.

What genotype were early psychologists interested in examining in connection to aggression?

XYY

What were individuals with a genotype of XYY often referred to as?

Super males

What did Jacobs et al (1965) find in Men in prison with a chromosomal abnormality?

3% of men in prison had this chromosome pattern.

What did Theilgaard (1984) find in XYY men compared to XY men?

XYY can cause an increase in height in individuals but not an increase in aggression.

What has the MAOA gene been associated with?

Aggression

What enzyme does the MAOA gene produce?

MAOA (Monoamine Oxidase A).

What is the MAOA enzyme responsible for?

Breaking down a number of neurotransmitters including serotonin as part of neurotransmission.

What is more commonly found in populations with a history of warfare?

MAOA-L gene

What is MAOA-L gene termed?

Warrior gene

What did Caspi et al (2002) find in boys with the MAOA-L gene?

Boys with the MAOA-L gene were significantly more likely than others to show aggressive behaviour when they grew up but only if they had also been treated badly as children.

What did Brunner et al (1993) find in male members of one Dutch family, regarding the MAOA gene?

These males had been repeatedly involved in impulsively aggressive behaviour such as rape, attempted murder and physical assault. Researchers found that these males had abnormally low levels of MAOA in their brains and possessed the MAOA-L gene.

What did findings from one study show about participants forcing an unpleasant substance?

That when provoked, MAOA-L participants displayed higher levels of aggression compared to participants who did not have this gene variant. ‘Aggression’ was operationalised as forcing a fictional participant to eat an unpleasant hot and spicy sauce.

What did Vassos (2014) find in a meta analysis into genetics and aggression?

Vassos instead claimed that hundreds of thousands of genes are likely interacting in very complex ways to determine aggression.

What does ethologists study?

Behaviours such as aggression shown by animals in their natural environments and believe it is appropriate to generalise their findings to humans.

What provides the adaptive function of aggression?

Seen in all animal species and is believed to be an innate behaviour

What did Lorenz (1966) propose about aggression in animals?

Often ritualistic, such as in the case of threat displays and appeasement rituals, rather than killing.

What is the built-in neural structure animals have that cause release of aggressive behavior?

Innate Releasing Mechanism (IRM).

What is the resulting aggressive behavioral response called?

Fixed Action Pattern (FAP).

What environmental trigger is activated by male sticklebacks?

If another male enters their territory displaying a red spot

What did Tinbergen investigate about FAPs?

in sticklebacks. He

What does Nisbett (1996) laboratory experiment suggest about aggression?

When South American white males were insulted they were more likely to respond aggressively than white North American males under the same conditions. This research demonstrates cultural differences in aggression

What example is given for environmental factors playing a more influential role?

Some dogs may chase cats but some dogs do not. The differences in behaviour may be down to training, or may be down to species differentiation as a result of selective breeding of characteristics.

What adaptive strategy is aggression seen as?

Solved a number of challenges for our ancestors, such as obtaining scarce resources and finding a mate.