Aggression Flashcards
What are the 2 hormonal mechanism in aggression?
Testosterene and Progesterone
What is testosterone?
An androgen responsible for the development of masculine features
What is the role of testosterone?
Regulating social behaviour
What is the role of progesterone?
Aggression in women
low levels of progesterone have increased aggression in women
What enzyme does the MAOA gene produce?
monoamine oxidase A
What does the MAOA gene do?
Regulates serotonin
What are the 2 neural mechanisms in aggression?
The Limbic system
The Orbitolfrontal cortex and serotonin
What 3 parts of the brain is the limbic system made up of?
Amygdala, Hippocampus, Hypothalamus
What is serotonin?
A neurotransmitter that regulates mood
What study did Dolan et al do between testosterone and aggression?
60 male offenders
past of aggressive impulsive behaviours
positive correlation with testosterone levels and aggression
What is the correlation between progesterone and aggression?
Negative correlation
What is the correlation between
testosterone and aggression?
Positive correlation
What are 2 evaluations of the hormonal mechanisms of aggression? (+-)
+ Evidence from animal studies
- Injecting female rats with T increased mouse-killing behaviour
- Castration of male rats reduced aggressive behaviour during mating season
- Dual Hormone hypothesis
- More than just testosterone linking to aggression
High T leads to aggression only when cortisol levels are low
High cortisol, Ts influence on aggression is blocked
What are 2 evaluations of the neural mechanisms of aggression? (+-)
- Other brain structures
- not just the limbic system are involved in aggression - The orbitofrontal cortex also plays a role and that not in the LS
+ Serotonin and drugs
- serotonin increasing drugs reduce aggression
Berman et al - Shocks to responses with a placebo and drug group
Those with drug gave fewer shocks than placebo
Link between serotonin and aggression
What are the 4 genetic factors of aggression?
Twin studies
MAOA gene
Adoption studies
Gene x Environment
What do twin studies say about genetics in aggression?
MZ twins are more likely to share aggressive behaviours compared to DZ twins as they share 100% of genes
Concordance rates
Direct physical assault - 50%MZ 19%DZ
Verbal aggression - 28%MZ 7%DZ
What do adoption studies say about genetics in aggression?
Link between an adopted child and their biological parent
Rhee and Waldman et al -
- meta analysis of adoption studies
- on direct aggression and antisocial behaviour
found variance rates of genetic influence on 41%
(Similar results to twin studies)
What does the MAOA say about genetics in aggression?
Regulates the neurotransmitter serotonin in the body, serotonin plays the role of impulsive aggression.
Low levels of the MAOA gene can lead to high levels of aggressive behaviour
What was Brunner et al’s study on the MAOA gene in aggression?
- 28 men from a large dutch family who had high levels of aggressive, violent criminal behaviours
- They had abnormally low rates of the enzyme MAOA
What does the gene x environment say about genetics in aggression?
Genes can not function in isolation.
It appears the MAOA gene variant activity is only related to adult aggression with early traumatic life experiences.
- Suggesting more of a diathesis - stress mode
What was Frazzeto et al’s study on gene x environment in aggression?
- Link between high antisocial aggression and MAOA variant in men who had significant trauma in the first 15 years of their life
- Those with no early childhood trauma did not really have high aggression levels as adults even with the MAOA variant.
What are 2 limitations on the genetic explanations of aggression?
Mertin money distributing task said they felt social norms
Complex MAOA link
Twin studies lack validity
What is a strength of genetic explanations of aggression?
Mertin et al-
Found more evidence to support the link between the MAOA - L variant and high levels of aggression
Men with high and low levels of MAOA gene took part in a money distributing game
Men with high MAOA variants were more cooperative and made fewer aggressive moves than those with the low MAOA variant.
Supports the relationship between the MAOA gene and aggression giving the explanation increased validity and credibility
What are the 4 factors in the ethological explanations of aggression?
- Innate releasing mechanism
- Adaptive function
- Ritualistic aggression
- Fixed action patterns