Neural + Hormonal Mechanisms in Aggression

Question 1

Neurotransmitters

Answer 1

Serotonin

Dopamine

Question 2

Serotonin

Answer 2

Thought to reduce aggression by inhibiting responses to emotional stimuli that might otherwise lead to an aggressive response

Question 3

Dopamine

Answer 3

Increases in dopamine activity via use of amphetamines have also been associated with increases in aggressive behaviour

Antipsychotics which reduce dopamine activity in the brain have been shown to reduce aggressive behaviour in violent delinquents

Question 4

Mann et al (serotonin)

Answer 4

Depleted people’s serotonin + using a questionnaire assessed hostility + aggression levels = drug treatment was associated with an increase in hostility + aggression scores in males not females

Question 5

Neurotransmitter research support

Answer 5

META

examined neurotransmitter levels in antisocial children + adults = found lower level of serotonin in indis described as being aggressive but found no sig rise or fall in dopa

Reduced levels of serotonin found in all antisocial groups but particularly in suicidal

Suggests serotonin depletion = impulsive behaviour which may lead to aggressive behaviour in various forms

Question 6

Hormonal Mechanisms

Answer 6

Testosterone

Cortisol

Question 7

Testosterone

Answer 7

High testosterone = high aggression

Question 8

Research on testosterone

Answer 8

Dabbs et al

Measured salivary testosterone in violent + non-violent criminals

Those with highest T = had history of primarily violent crimes, where as those with lowest levels = committed non-violent crimes

Question 9

The challenge hypothesis

Answer 9

In monogamous species, T levels should only rise above baseline breeding level in response to social challenges = male-male aggression

Suggests human T levels would rise sharply in response to such challenges

Question 10

Cortisol

Answer 10

Increases anxiety + likelihood of social withdrawal

High levels inhibit testosterone level + so inhibit aggression

Question 11

Research on Cortisol

Answer 11

Low levels of cortisol in habitual violent offenders + violent school children

Suggests that although relatively high testosterone is the primary biochemical influence on aggression, low cort plays important role by increasing likelihood of aggressive behaviour

Question 12

Archer

Answer 12

Meta

Found low +ve correlation between testosterone + aggression

However type of P + form of measurement of aggression differed between studies

Question 13

Reductionism + Biological methods

Answer 13

Link tween biological mechanisms (Test + Sero) with aggression are well established in non-human animals

Not so clear with humans

Doesn’t deny link but states the complexity of human social behaviour means that a biological explanation for human aggression is insufficient on its own to explain all aspects of aggression

Question 14

Raleigh et al

Answer 14

Vervet Monkeys on high serotonin diet showed decreased levels of aggression + those on low serotonin = high aggression

Suggests difference in aggression could be attributed to their serotonin levels

Question 15

Other evidence for importance of serotonin

Answer 15

Animals selectively bred for domestication + for increasingly docile temperaments = increase over time in concentration of serotonin in brain

Question 16

Evidence of Sero from antidepressants

Answer 16

Antidepressant drugs designed to elevate serotonin levels = reduce irritability + impulsive aggression

Question 17

Gender Bias

Answer 17

Most studies concerned with testosterone + aggression have involved males

Research shows that females with higher testosterone levels had higher occupational status, could be due to assertiveness

Also could make women act nicer depending on situation = rather than directly increasing aggression, testosterone promotes status seeking behaviour of which aggression is one type

Question 18

Weakness of Testosterone research

Answer 18

Despite many studies showing a +ve correlation between testosterone + aggression, others find no such relationship, particularly those that have compared test levels of aggressive + less aggressive indis

Most studies showing a +ve correlation have used small samples of men within prisions

Question 19

Support for Cortisol

Answer 19

4 year study of boys with behavioural studies

Boys with consistently low cort levels began antisocial acts at younger age + more aggressive

Compared to boys with higher or fluctuating costisol levels

Question 20

Real-world Application

Answer 20

Male college students = saliva sample before handling either gun or toy, and after

Gun = sig greater increases in testosterone + behaved more aggressive

Suggests why presence of guns in environment leads to increased aggression