Genetic Factors Flashcards
AO1 What is determining the role of genetic factors essentially a question of?
Nature vs nurture
AO1 What approach are explanations such as genetics play a role linked with?
Biological approach
AO1 What do biological approaches believe regarding aggression?
The prosperity for aggression lies in an individuals genetic makeup
AO1 In order to establish the genetic influences behind aggression, what has research mainly focused on?
Twin and adoption studies
AO1 What are identical twins called?
Monozygotic
AO1 What are non-identical twins called?
Dizygotic
AO1 In twins, monozygotic twins..
share all of their genes, whereas non-identical twins share 50%
AO1 Studies focus on comparing the degree of similarity for a particular trait (aggression, in this case)..
as if MZ twins are alike in terms of aggressive behaviour, then this should be attributed to genes rather than the environment
AO1 Coccaro studied..
- Aggression in twin adult pairs
- Nearly 50% of variance in aggression could be accredited to genetic factors
AO1 What do the results of Coccaros research show?
Suggest that genes do have a strong influence over our levels of aggression in addition to environmental factors, thus providing substantial evidence to support the role of genetics
AO1 In adoption studies, what can imply a genetic effect?
A positive correlation between aggressive behaviour in an adopted child and aggressive behaviour in their biological parent.
AO1 However, if there is a correlation between the adoptees aggression and aggressive behaviour from their adopters, what is implied?
An environmental effect
AO1 The idea of a genetic effect in adopted children is supported by what?
- Study of 14,000 adoptions in Denmark
- Signif. number of adopted boys with criminal convictions had a biological parent with a criminal conviction also
- Provides evidence to support the role of genetic factors
AO3 Methodologically, why can research into adoption studies be credited?
Large sample size, meaning they are likely to have good generalisability and be highly reliable
AO1 What is a gene associated with aggressive behaviour?
MAOA
AO1 What does MAOA do?
Regulates metabolism of serotonin in the brain, low levels of which are known to influence aggression
AO1 Which study demonstrates the role of MAOA?
1980 study of a Dutch family
AO1 What was found in the 1980 study of a Dutch family?
- Abnormally low levels of MAOA due to a gene defect
- Men acted in particularly violent and aggressive manners with many involved in serious crimes such as rape
- Provides support for the role of genetics
AO2 The link between the MAOA gene and aggressive behaviour was investigated by..
Capsi in a study of 500 male children
AO2 What did Capsi find?
- Those with low MAOA levels were significantly more likely to grow up and exhibit antisocial behaviour
- But ONLY in those who had been maltreated
- Those with low levels who had not been mistreated did not exhibited same behaviours
What do Capsi’s findings show?
That it is a gene/environment interaction that is a determinant of aggressive behaviour rather than genetics alone
AO3: However, what is a limitation of Capsi’s study?
- Only male children were used which lacks generalisability
- We do not know if the gene affects females so cannot draw conclusions that apply to both genders/all age and cultural groups
- Could lead to false stereotypical beliefs about female aggression
Contrasting to the perceived role of MAOA in influencing aggression…
It has been suggested that no specific gene for violent crime
- Inherited temperamental or personality characteristics may place individuals at higher risk
What do adoption studies show, related to the idea that there may not be a specific gene for aggression?
Highest rates of criminal violence occurs when both biological and adoptive parents have a history of violence (G/E interaction)
However, when the criminal history of an adopted male was compared with the criminal history of both biological parents and adoptive parents,
- G influences were significant in property crime but not violent crimes
- Conflicting support in terms of the role played by genetics in aggressive behaviour
- Complex and cannot be generalised to all crimes
What is a criticism of the idea that genetic factors are associated with aggression’s assessment?
Research methods have been found to reduce the reliability of studies by influencing results
What are some research methods associated with Miles and Carey’s studies?
- Self report methods used to assess violence explained a large proportion of the variance in violence
- Observational methods showed no difference between mZ and dZ twins
What do the methodological flaws of Miles and Carreys findings suggest?
Differences in aggression were due to environmental factors rather than genetic
Overall, what do the research limitations suggest about the role of genetics?
- Questions the reliability
- Influence of genetics or influence of methods used to collect data?
Poorly designed earlier studies into inheritance of criminal violence suggest a strong correlation between genetics and crime..
- But studies fail to distinguish important factors such as violent/non violent
- Only focuses on extremes (convicted) so lacks generalisability
- May not necessarily be violent criminals if only a one off crime
What is the proper AO2 for the poorly designed studies..point?
- Offers a possible explanation therefore why so many studies have found little or no evidence of heritability of violence - if studies are unable to collect real data from crimminals
