Genetic Factors Flashcards
What does this suggest about aggression?
It is possible that high levels of testosterone or fluctuating levels of serotonin could be genetically determined because of the individual’s predisposition
How are genetic factors measured?
They are investigated through twin and adoption and family studies. Looking at concordance rates, if one twin is aggressive is the other? If yes, then it indicates a genetic link
What is the role of the MAOA gene?
It is an enzyme that breaks down important neurotransmitters in the brain including dopamine, noradrenaline and serotonin. There are variations of this gene found in humans as some people produce less of the MAOA gene whilst others produce higher levels of the gene
How is the MAOA gene implicated in aggression?
Studies have found a correlation between the low activity form of the MAOA gene and aggression. This is because the low activity form creates a higher level of neurotransmitters because the excess amounts are not mopped up
How does the MAOA gene link with the environment?
The shortened version of the MAOA gene doesn’t automatically cause aggression as this seems to only occur if they have been abused as a child so therefore aggression is sensitive to social experiences in early development
Who conducted the first study to support the role of the MAOA gene and what did he do and find?
Brunner. He studied 5 men in a family in the Netherlands and found that they all possessed the low activity version of the MAOA gene. He found this through monitoring urine samples and found that they had excess monoamines because they didn’t have enough MAOA to mop up the excess. Therefore there is a link between the MAOA gene and increased levels of aggression
Who conducted the second study into the MAOA gene and what did they do and find?
Caspi et al. Studied 500 males over 26 years. Antisocial behaviour was measured and those with the genotype for high MAOA activity were far less likely to behave anti socially. Those with the low MAOA activity and who had been maltreated as a child were more likely to display anti social behaviour. This shows that there is a genetic variant for MAOA but only when certain environmental factors occur therefore interactionist view should be taken
Who conducted the third study to support the MAOA gene and what did they find?
Mattson found that MAOA deficient male mice attacked new mice introduced into their cage and failed to establish usual dominant submissive relationships
What are five limitations of the MAOA gene affecting aggression?
- small samples in studied
- research conducted on animals
- gender bias especially beta bias as MAOA is not often expressed in women
- there is an issue with separating genetics and the environment
- reductionist theory
What is a strength of the MAOA gene affecting aggression?
Evolutionary advantages as it gives a competing edge and risk taking behaviour is more likely. This may be more attractive to opposite sex and therefore makes reproduction more likely
Who does genetic factors in aggression link to issues and debates?
- gender bias as MAOA not expressed in women
- deterministic as biological theory
- nature as due to biological mechanisms
- reductionist as biological theory
