Aggression 1
Neural and hormonal mechanisms
14-01-21
Neural mechanisms
In our brain we have a network of structures
o The Limbic System
o It is related to aggression
The amygdala
Plays a key role in humans and animals
Impacts our response to an environment, threats and challenges
The limbic system
Gospic et al 2011
Used a lab experiment to assess aggressive behaviour
o Proposer offers to split a sum of money
o If the responder accepts then the money is split
o During the game they underwent an fMRI
o When unfair offers were rejected, the amygdala was very active
o Benzodiazepine was a drug that was found to be effective at reducing
activity in the area
Serotonin
Neurotransmitter
Has inhibitory effects on the brain
o Slows and dampens neuronal activity
Normal levels are linked with reduced firing of neurones = Self-control
Decreased levels disturb the mechanisms = No self-control = Aggression
Virkkunen et al (1994)
o Compared levels of serotonin in the breakdown of products
o Looked at violent impulsive and violent non-impulsive
o Found that levels were lower in impulsive offenders
o Also that they experienced more sleep irregularities
Serotonin also regulates sleep patterns
o Disturbances are known to affect aggression levels
Hormonal mechanisms
Testosterone and progesterone
Observed that men are more aggressive than women
Testosterone is believed to impact this
o It regulates social behaviour
o Male sex hormone
Giammanco et al (2005)
o Used animal studies to show that increases in testosterone are greater
related to aggressive behaviour
Dolan et al (2001)
o Found a positive correlation between testosterone levels and aggression
in male maximum security hospitals
Evidence shows that progesterone affects aggression in women
Exam questions
Neural and hormonal mechanisms
14-01-21
Neural mechanisms
In our brain we have a network of structures
o The Limbic System
o It is related to aggression
The amygdala
Plays a key role in humans and animals
Impacts our response to an environment, threats and challenges
The limbic system
Gospic et al 2011
Used a lab experiment to assess aggressive behaviour
o Proposer offers to split a sum of money
o If the responder accepts then the money is split
o During the game they underwent an fMRI
o When unfair offers were rejected, the amygdala was very active
o Benzodiazepine was a drug that was found to be effective at reducing
activity in the area
Serotonin
Neurotransmitter
Has inhibitory effects on the brain
o Slows and dampens neuronal activity
Normal levels are linked with reduced firing of neurones = Self-control
Decreased levels disturb the mechanisms = No self-control = Aggression
Virkkunen et al (1994)
o Compared levels of serotonin in the breakdown of products
o Looked at violent impulsive and violent non-impulsive
o Found that levels were lower in impulsive offenders
o Also that they experienced more sleep irregularities
Serotonin also regulates sleep patterns
o Disturbances are known to affect aggression levels
Hormonal mechanisms
Testosterone and progesterone
Observed that men are more aggressive than women
Testosterone is believed to impact this
o It regulates social behaviour
o Male sex hormone
Giammanco et al (2005)
o Used animal studies to show that increases in testosterone are greater
related to aggressive behaviour
Dolan et al (2001)
o Found a positive correlation between testosterone levels and aggression
in male maximum security hospitals
Evidence shows that progesterone affects aggression in women
Exam questions
