Structures of the brain - Aggression

Question 1

How can brain damage cause aggression?

Answer 1

• Abnormalities in the prefrontal cortex = less control of impulses as the lymbic system could be able to make decisions with out the PC being able to inhibit it
• Abnormalities/increased size of amygdala = increase of angry emotions

Question 2

How does serotonin increase aggression?

Answer 2

Low levels = less able to inhibit aggressive impulses

Question 3

Why is serotonin hard to measure?

Answer 3

Can be tested through cerebral spinal fluid or through levels of receptors in the brain. Can only look for receptors after death. (ISSUE = hard to tell if aggressive people lack it)
- If there are more receptors than usual, the brain has chronic low levels of serotonin

Question 4

How does dopamine increase aggression?

Answer 4

• High levels of dopamine are associated with high levels of aggression. Provides reward after aggressive behaviours
• Amphetamine abuse increase dopamine and is also associated with aggressive behaviour

Question 5

What did Rainea do?

Answer 5

Studied murderers pleading not guilty by reason of insanity claiming brain dysfunction.

Question 6

What did Rainea find?

Answer 6

• Murderers were characterised by reduced glucose metabolism (brain isn’t working as much) in the prefrontal cortex.
• Abnormal activity in the amygdala = suggesting they would be more aggressive

Question 7

What did Mann et al find?

Answer 7

Drug dexfenfluramine depletes serotonin levels in the brain = aggression increased among males but not females

Question 8

What did Couppis et al find?

Answer 8

Dopamine causes individuals to seek out aggression because of the rewarding sensations

Question 9

What is the real world applications issue?

Answer 9

Should violent offenders be punished if they have damage to the prefrontal cortex = is it their fault they’re aggressive?

Question 10

What is the nature/nurture issue?

Answer 10

Nature explanation could be that individuals are born with a brain malfunction in the prefrontal cortex or amygdala

Question 11

What did Ferrari et al do?

Answer 11

Tested the influence of serotonin and dopamine on rats aggression:

• allowed the rat to fight everyday for 10 days
• on 11th day the rat was not allowed to fight

Question 12

What did Ferrari et al find?

Answer 12

On the 11th day in anticipation of a fight dopamine levels were high and serotonin levels were low

Question 13

What does Ferrari et al’s study show?

Answer 13

Experience had changed brain chemistry = created aggression

Question 14

How does PAS relate to Ferrari’s study?

Answer 14

May not be able to generalise to humans who are more complex