genetic factors in aggression
- Created by: mollskie49
- Created on: 09-06-13 14:37
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- genetic factors in aggression
- Twin studies
- Monozygotic (MZ – identical) twins and dizygotic (DZ- share 50% DNA). If MZ twins are alike in aggressive behaviour it is due to their genes not environment
- Coccao et al – nearly 50% of variance in direct aggressive behaviour could be due to genetic factors
- Monozygotic (MZ – identical) twins and dizygotic (DZ- share 50% DNA). If MZ twins are alike in aggressive behaviour it is due to their genes not environment
- Adoption studies
- If positive correlation between aggressive behaviour in adopted kids and aggressive behaviour in their biological parents then genetic effect implied
- If positive correlation found between adoptee and rearing family’s aggressive behaviour then environmental effect
- 14000 adoptions, Denmark - significant number of adopted boys w/ criminal convictions had biological parents w/ criminal convictions – Hutchings and Mednick
- If positive correlation found between adoptee and rearing family’s aggressive behaviour then environmental effect
- If positive correlation between aggressive behaviour in adopted kids and aggressive behaviour in their biological parents then genetic effect implied
- a gene for aggression
- the role of MAOA
- There is no individual gene but gene responsible for producing a protein (monoamine oxidase A - MAOA) is associated with aggression and low levels of serotonin
- Dutch family, many male members behaved in very aggressive manner e.g. arson/**** and found to have low levels of MAOA – Bruner et al
- There is no individual gene but gene responsible for producing a protein (monoamine oxidase A - MAOA) is associated with aggression and low levels of serotonin
- Gene-environment interaction
- Caspi et al – 500 male kids. Those with low levels of MAOA more likely to grow up and exhibit antisocial behaviour but only if they had been maltreated as kids
- Children with high levels of MAOA who were maltreated and those with low levels who were not maltreated did not display antisocial behaviour
- Shows interaction between genes and environment determines behaviour.
- Children with high levels of MAOA who were maltreated and those with low levels who were not maltreated did not display antisocial behaviour
- Caspi et al – 500 male kids. Those with low levels of MAOA more likely to grow up and exhibit antisocial behaviour but only if they had been maltreated as kids
- the role of MAOA
- Genetics and violent crime
- Researchers claim inherited temperament or personality characteristics place some people more at risk
- When adopted children have both biological and adoptive parents with a history of violent crime they are at more risk of committing violent crime
- Gene-environment interaction theory
- Genetic influences were significant in cases of property crime but not in case of violent crime – Brennan and Mednick
- Gene-environment interaction theory
- When adopted children have both biological and adoptive parents with a history of violent crime they are at more risk of committing violent crime
- Researchers claim inherited temperament or personality characteristics place some people more at risk
- Difficulties of determining role of genetic factors
- Hard to establish genetic cause because more than one gene contributes to a given behaviour
- Many genetic and non genetic factors
- Influences may interact with each other
- Supports Caspi’s gene-environment interaction study
- Influences may interact with each other
- Many genetic and non genetic factors
- Hard to establish genetic cause because more than one gene contributes to a given behaviour
- Problems of assessing aggression
- Parent or self-report or observational techniques
- Miles and Carey – Meta analysis – mode of assessment found to be a significant moderator of aggressive behaviour
- Genetic factors explained in large proportion of variance in aggressive behaviour in studies using parental/self-reports
- Observational techniques showed significantly less genetic contribution and more influence of environmental factors
- Bandura et al – Bobo doll study – no difference in correlations between MZ and DZ twins
- Suggesting individual difs in aggression were more product of environmental influence than genetic factors – Plomin et al
- Bandura et al – Bobo doll study – no difference in correlations between MZ and DZ twins
- Observational techniques showed significantly less genetic contribution and more influence of environmental factors
- Genetic factors explained in large proportion of variance in aggressive behaviour in studies using parental/self-reports
- Miles and Carey – Meta analysis – mode of assessment found to be a significant moderator of aggressive behaviour
- Parent or self-report or observational techniques
- Methodological limitations
- Studies using genetic factors often fail to distinguish between violent and non-violent crime, making it more difficult to untangle the role of genetic factors in specifically aggressive violence
- Also fail to distinguish between criminals who are habitually violent and those who performed the violent crime as a one-off
- Studies using genetic factors often fail to distinguish between violent and non-violent crime, making it more difficult to untangle the role of genetic factors in specifically aggressive violence
- IDA - Real World Application
- Too unstable for actual immediate application but raises concerns because some links have been shown
- Twin studies
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