Describe and evaluate one or more of the following biological explanations for
human aggression: neural, hormonal, genetic. (Awarded 16/16)
One biological explanation for human aggression is the hormonal explanation.
Testosterone is a hormone predominantly found in males (although low amounts
are found in females), which is produced in the testes and enhances the sex
drive, also believed to regulate emotions and actions such as aggression.
Throughout the male lifetime, testosterone levels peak at adolescence and
slowly reduces as they grow older. Most research into the effect of testosterone
on aggression happens in institutions such as prisons, mental institutions, and
hospitals. Although such research would have high ecological validity due to the
natural settings used, it could be argued to be gender biassed, as most of the
research predominantly focusses on males, not females, despite them also
holding testosterone in their bodies. However, Van Goozen’s research into
transgender individuals would counterargue this. They investigated aggression
levels in people going through sex changes by hormonal treatment and found as
such: people transitioning from female to male on testosterone injections had
increasing aggression issues, whereas those transitioning from male to female on
oestrogen had decreasing aggression levels. Therefore, research evidence has
supported the effect of testosterone on aggression. To further support this,
animal studies have been conducted on mice by Wagner to further attempt to
prove testosterones effect on aggression. Wagner castrated a group of mice, in
order to measure how this would affect how aggressive they became. After
castration, their aggression levels were low, however, after being reinjected with
testosterone, they became aggressive again. Despite this research being useful,
it does pose issues. One issue with Wagner’s experiment is that only male mice
were used, and therefore, the findings would not be generalisable to all mice,
having a gender bias. A further issue is that the research findings of animals may
not be generalisable to humans, as there may be too many hormonal
differences.
A further biological explanation for human aggression is the genetic explanation.
The MAOA gene (the warrior gene) is a gene which regulates neurotransmitters
such as serotonin in the brain. However, sometimes, the gene becomes mutated
and starts to lose its functions, not allowing enough serotonin in the brain. This
often leads to outbursts of anger, which is why it is linked to aggression. On top
of this, the mutated MAOA gene is often found in criminals, and is more
identifiable in people with skin conditions such as acne. Like the mutated MAOA
gene, the XYY, or ‘supermale’ gene, is also associated with aggression. The
mutated chromosome, specifically found in males, also leads to low levels of
serotonin, leading to aggressive behaviour. However, research evidence has not
concluded whether this is a direct cause of aggression or not. Using only genetic
factors such as genes or chromosomes disputes the effect that nurture has on
aggression. The psychologist, Meaney, would argue that aggression is based on
the person’s upbringing, and presented this through a study they conducted on
rats. One rat was a mother who constantly showed her baby affection through
licking them, and the other was a mother who neglected her child, ignoring them
constantly. The child who was licked grew up to be a loving mother to her own
baby, whereas the neglected rat also acted neglectful to her own children.
However, when the next two babies were swapped, the rat born from the
neglectful mother who lived with the loving mother, grew up to be loving.
human aggression: neural, hormonal, genetic. (Awarded 16/16)
One biological explanation for human aggression is the hormonal explanation.
Testosterone is a hormone predominantly found in males (although low amounts
are found in females), which is produced in the testes and enhances the sex
drive, also believed to regulate emotions and actions such as aggression.
Throughout the male lifetime, testosterone levels peak at adolescence and
slowly reduces as they grow older. Most research into the effect of testosterone
on aggression happens in institutions such as prisons, mental institutions, and
hospitals. Although such research would have high ecological validity due to the
natural settings used, it could be argued to be gender biassed, as most of the
research predominantly focusses on males, not females, despite them also
holding testosterone in their bodies. However, Van Goozen’s research into
transgender individuals would counterargue this. They investigated aggression
levels in people going through sex changes by hormonal treatment and found as
such: people transitioning from female to male on testosterone injections had
increasing aggression issues, whereas those transitioning from male to female on
oestrogen had decreasing aggression levels. Therefore, research evidence has
supported the effect of testosterone on aggression. To further support this,
animal studies have been conducted on mice by Wagner to further attempt to
prove testosterones effect on aggression. Wagner castrated a group of mice, in
order to measure how this would affect how aggressive they became. After
castration, their aggression levels were low, however, after being reinjected with
testosterone, they became aggressive again. Despite this research being useful,
it does pose issues. One issue with Wagner’s experiment is that only male mice
were used, and therefore, the findings would not be generalisable to all mice,
having a gender bias. A further issue is that the research findings of animals may
not be generalisable to humans, as there may be too many hormonal
differences.
A further biological explanation for human aggression is the genetic explanation.
The MAOA gene (the warrior gene) is a gene which regulates neurotransmitters
such as serotonin in the brain. However, sometimes, the gene becomes mutated
and starts to lose its functions, not allowing enough serotonin in the brain. This
often leads to outbursts of anger, which is why it is linked to aggression. On top
of this, the mutated MAOA gene is often found in criminals, and is more
identifiable in people with skin conditions such as acne. Like the mutated MAOA
gene, the XYY, or ‘supermale’ gene, is also associated with aggression. The
mutated chromosome, specifically found in males, also leads to low levels of
serotonin, leading to aggressive behaviour. However, research evidence has not
concluded whether this is a direct cause of aggression or not. Using only genetic
factors such as genes or chromosomes disputes the effect that nurture has on
aggression. The psychologist, Meaney, would argue that aggression is based on
the person’s upbringing, and presented this through a study they conducted on
rats. One rat was a mother who constantly showed her baby affection through
licking them, and the other was a mother who neglected her child, ignoring them
constantly. The child who was licked grew up to be a loving mother to her own
baby, whereas the neglected rat also acted neglectful to her own children.
However, when the next two babies were swapped, the rat born from the
neglectful mother who lived with the loving mother, grew up to be loving.
