Aggression - role of neural and hormonal mechanisms

Question 1

Brown (serotonin)

Answer 1

• waste product of serotonin low for people who display impulsive/aggressive behaviour
• non-experimental ad observational
• hard to draw conclusions about causality as unclear about direction

Question 2

Mann (serotonin)

Answer 2

• among males, hostility and aggression levels increased after using dexfenfluramine (reduces level of serotonin in the brain)
• questionnaire - self report
• experimental as manipulated IV
• allows conclusions about causality to be drawn
• in males, not females
• social desirability may have hidden effect in females - dangerous to conclude that serotonin doesn’t cause aggression in females

Question 3

Ferrari (serotonin)

Answer 3

• allowed rat to fight everyday at specific day
• on the 11th day rat was not allowed to fight
• serotonin levels decreased
• experimental
• animal, hard to generalise to humans

Question 4

Lavine (dopamine)

Answer 4

• increases in dopamine activity via the use of amphetamines are associated with increase in aggressive behaviour

Question 5

Buitelaar (dopamine)

Answer 5

• use of antagonists (drug which reduces normal activity of neurotrasmitters in the brain such as dopamine) have been used successfully to reduce aggressive behaviour

Question 6

Ferrari (dopamine)

Answer 6

• rat’s dopamine level increased in anticipation of fight

Question 7

Couppis (dopamine)

Answer 7

• evidence that dopamine plays important reinforcing role in aggression
• some individuals intentionally seek out aggressive encounters because of rewarding sensations caused by increased dopamine

Question 8

Bard and Mountcastle (brain structure; hypothalamus)

Answer 8

• lesioning cats’ higher and lower brains

- concluded that hypothalamus initiates aggressive behaviour

Question 9

Flynn (brain structure; hypothalamus)

Answer 9

• stimulated lateral hypothalamus in cats, showed predotorial aggression
• stimulating medial hypothalamus showed more vicious attack behaviour

Question 10

Zagrodzka (brain structure; amygdala)

Answer 10

• using cats

- showed damage to amygdala was significant factor in predator attacks

Question 11

Phineas Gage (brain structure; frontal lobe)

Answer 11

• damage led to aggressive behaviour
• as Gage did not exhibit this behaviour before the accident it is plausible that the frontal lobe, if damaged, has an effect on aggressive behaviour

Question 12

Delgado (role of brain structure)

Answer 12

• stimulated brain region of a bull
• bull immediately stopped being aggressive
• particular nucleus has been shown to affect voluntary movement, questionable as to whether this really relates to aggression

Question 13

Nelson (testosterone)

Answer 13

• positive correlation between level of testosterone and aggressive behaviour in female and male prisoners
• testosterone was not measured at precise point when aggressive act was performed

Question 14

Wagner (testosterone)

Answer 14

• male mouse castrated then levels of aggression tend to reduce
• if castrated mouse recieves testosterone then aggression levels increase
• manipulation of the variable, cause and effect can be drawn

Question 15

Mazur and Booth (testosterone)

Answer 15

• 2100 air force veterans over 10 year period
• testosterone levels varied, reduced when married and increased when divorced
• supports reciprocal model

Question 16

Kouri (testosterone)

Answer 16

• double-blind procedure
• men given either doses of testosterone or placebo
• paired with fictional partner, told by pushing a button they could reduce amount of cash their partner recieved
• told their partner was reducing amount of cash for them
• those who recieved testosterone pushed button significantly more times
• supports basal model