“Outline and evaluate genetic factors in aggression”
A01 –
To distinguish whether aggression is the result of genetic inheritance or
the product of environmental influences, researchers have employed a
variety of methodological techniques, including: twin studies, adoption
studies and studies of individual genes.
TWIN STUDIES
Monozygotic (identical) twins share all genes, dizygotic (non-identical)
twins share only 50%.
Researchers compare the degree of similarity for a particular trait (such as
aggression) between sets of monozygotic twins and to the similarity
between sets of dizygotic twins.
If the monozygotic twins are more alike in terms of their aggressive
behaviour then this should be due to genes rather than environment.
ADOPTION STUDIES
If a positive correlation is found between aggressive behaviour in adopted
children and aggressive behaviour in their biological parents, a genetic
effect is implied.
If a positive correlation is found between the adoptees aggressive
behaviour and the adopted children, then an environmental effect is
implied.
AGGRESSION GENE
A gene responsible for producing the protein MAOA has been associated
with aggressive behaviour.
MAOA regulates the metabolism of serotonin in the brain, and low levels of
serotonin are associated with impulsive and aggressive behaviour.
A02 –
RESEARCH 1 – Hutchings and Mednick (1975)
POINT – supports the idea of a genetic effect in terms of aggression.
EVIDENCE – conducted a study of over 14,000 adoptions in Denmark and found
that a significant number of adopted boys with criminal convictions had
biological parents (particularly fathers) with criminal convictions.
EXPLAIN – this provides evidence for a genetic effect because it shows how
aggression seemed to pass from parents to children despite the fact that the
children were not raised by their biological parents.
EVALUATE – weakness – only conducted on males – so may be subject to gender
bias – this may make it difficult to generalise the results to females – so reduces
the generalizability of the findings – weakens research support.
A01 –
To distinguish whether aggression is the result of genetic inheritance or
the product of environmental influences, researchers have employed a
variety of methodological techniques, including: twin studies, adoption
studies and studies of individual genes.
TWIN STUDIES
Monozygotic (identical) twins share all genes, dizygotic (non-identical)
twins share only 50%.
Researchers compare the degree of similarity for a particular trait (such as
aggression) between sets of monozygotic twins and to the similarity
between sets of dizygotic twins.
If the monozygotic twins are more alike in terms of their aggressive
behaviour then this should be due to genes rather than environment.
ADOPTION STUDIES
If a positive correlation is found between aggressive behaviour in adopted
children and aggressive behaviour in their biological parents, a genetic
effect is implied.
If a positive correlation is found between the adoptees aggressive
behaviour and the adopted children, then an environmental effect is
implied.
AGGRESSION GENE
A gene responsible for producing the protein MAOA has been associated
with aggressive behaviour.
MAOA regulates the metabolism of serotonin in the brain, and low levels of
serotonin are associated with impulsive and aggressive behaviour.
A02 –
RESEARCH 1 – Hutchings and Mednick (1975)
POINT – supports the idea of a genetic effect in terms of aggression.
EVIDENCE – conducted a study of over 14,000 adoptions in Denmark and found
that a significant number of adopted boys with criminal convictions had
biological parents (particularly fathers) with criminal convictions.
EXPLAIN – this provides evidence for a genetic effect because it shows how
aggression seemed to pass from parents to children despite the fact that the
children were not raised by their biological parents.
EVALUATE – weakness – only conducted on males – so may be subject to gender
bias – this may make it difficult to generalise the results to females – so reduces
the generalizability of the findings – weakens research support.
