Biological theory of aggression Flashcards
What did sequencing in the Bruner study reveal?
It revealed the genetic abnormality to be a missense mutation resulting in a dysfunctional MAOA gene
What did the Dutch males produce more of?
They produced dramatically raised levels of monoamines serotonin and noradrenalin as a result of a dysfunctional MAOA
What did meta analysis of twin and adoption studies conclude about genetic factors?
They concluded that genetic factors account for between 40%-50% of the variance in aggressive behaviour
What does the 40-50% variance suggest?
It suggests that aggression as a characteristic is highly heritable
Who conducted a depletion study?
Kim et al 1997
What did kim do?
Kim removed the MAOA gene from mice
Kim found that the knockout mice with dramatically elevated levels of monoamines are hyper aggressive and demonstrate extreme fear responses
True or false
True
What else did the Kim study show?
It showed that elevated levels of monoamines during the development and growth of the brain change structure and function
What is the more common version of the MAOA called?
MAOA L
Who studied the Dutch family ?
Brunner
Aggression can be adaptive and serve a fitness advantage it’s likely to have what ?
A genetic component
Why were historical aims to isolate the Y chromosome flawed?
Due to poor methodology
Describe the relationship between aggression and genes
Highly complex with multiple genetic variants contributing and interacting with each other and the environment
What does MAOA do?
It oxidises monoamines
Who came up with landmark research linking a single rate genetic mutation to high levels of aggressive behaviour?
Brunner
What did Kim’s mice demonstrate ?
They demonstrated extreme fear responses
What did the depletion studies show?
It shows how elevated levels of monoamines during development and growth of the brain can change brain structure and function
If a male has the MAOA L gene what will his behaviour be like?
He has the potential to be particularly aggressive however ONLY with an adverse childhood
What did Caspi 2002 studies show?
The complexity of genes and the environment
MAOA L and childhood
Genes can predispose not determine behaviour and can act differently in different environment
True or false
And who concluded this statement
Caspi
True
What were Caspi’s strengths?
Large sample - 1000+ Even male female ratio Human sample Prospective design Reliability - replication by Kim-Cohen 2006
Who replicated Caspi’s findings in a large scale meta analysis
Kim Cohen 2006
Who extended the knowledge of mechanism of MAOA L gene?
Meyer-linenberg
Under in necessary environmental conditions what can happen to brain structure and chemistry according to lindenberg
The limbic system and prefrontal cortex reduction. Hyperactivity of amygdala.
