Biological Explanations for Aggression
Neural Explanations for Aggression
The limbic system and serotonin
Neural refers to the nervous system – the CNS and the PNS. These are part of the
biological explanation for aggression which stresses internal and physiological factors
rather than external/psychological ones. In the aggression topic we will focus on the
roles of the limbic system within the brain and the neurotransmitter serotonin.
The limbic system
The limbic system is subcortical (below the cortex) and therefore deep within the brain
The limbic system has a crucial role to play in emotional behaviour. It includes a number
of different components but the two most important for aggression are the amygdala and
the hippocampus.
The role of the amygdala is to:
1. Identify our emotional state in response to an external stimulus
2. Launch a behaviour (e.g. aggression) which satisfies this emotional state
This is responsible for quickly evaluating the emotional importance of sensory
information and prompting an appropriate response.
The role of the hippocampus is to:
1. Search our LTM for how we responded in similar situations in the past and to
consider the outcome of those responses. Therefore, if we used aggression in a
similar situation in the past and the outcome was not positive, the hippocampus
could brake or check the aggressive impulse from the amygdala.
,This is involved with the formation of long-term memories, and so allows an animal to
compare the conditions of a current threat with similar past experiences. For example,
if an animal had previously been attacked by another animal, the next time they encounter
that animal they are likely to respond either with aggression or fear, whichever is more
appropriate. Impaired hippocampal function prevents the nervous system from putting
things into a relevant and meaningful context, and so may cause the amygdala to respond
inappropriately to sensory stimuli, resulting in aggressive behaviour.
A03
Point Evidence Conclusion
A strength of the neural Many of the studies listed This is a strength of the
explanation is that the below were conducted in neural explanation as it
research adopts a laboratory conditions and suggests that the evidence
scientific approach to are based on the researcher on which it is based has
study and is able to manipulating levels of internal validity.
demonstrate cause and serotonin and observing
effect (for serotonin). and recording the effects
on levels of aggression.
A weakness of the neural Both the limbic system and This is a weakness of the
explanation is that it could serotonin explanations neural explanations as it
be seen as overly could be seen as overly ignores the argument that
deterministic. deterministic as they individuals have free will
suggest that aggressive and choose to act
behaviour is determined aggressively or not. This has
by internal factors that are clear implications for the
beyond our control. criminal justice system; if
an individual’s aggression is
determined by neural
factors, they cannot be
held responsible for their
aggressive behaviour.
Evidence to support the Gospic found that when This supports neural
amygdala’s role in the responders aggressively explanations for aggression
limbic system as part of the rejected an unfair offer as it suggests a link
neural explanation for from the proposer in “The between the
aggression comes from the Ultimatum Game”, fMRI responsiveness of the
work of Gospic. scans of their brains amygdala and aggression.
revealed a fast and
heightened response by
the amygdala.
Evidence to support the Kluver and Bucy found that This supports the
amygdala’s role as part of destroying the amygdala importance of the limbic
, the limbic system / neural of a dominant monkey system as an explanation
explanation for aggression caused it to lose its for aggression as without
comes from the work of dominant position within its amygdala, the monkey
Kluver and Bucy. the hierarchy. no longer responded to
external threats with
aggression.
The Kluver and Bucy study The Kluver and Bucy study The use of NHAs may
may not provide valid data is based on studying non- undermine the usefulness
to support the neural human animals. of the study in terms of the
explanation of aggression. extent to which its findings
can be used to support
neural explanations of
aggression amongst
humans.
Evidence to support the Boccardi et al found that This supports the neural
role of the hippocampus in habitually violent explanation for aggression
the limbic system as part of offenders exhibited as those with hippocampal
the neural explanation for abnormalities of abnormalities were less
aggression comes from hippocampal functioning. able to put sensory
Boccardi et al. information into a valid
and meaningful context,
making a more aggressive
response from the
amygdala more likely.
2nd part of the neural explanation:
- Serotonin
As with the limbic system, serotonin is part of the biological explanation for
aggression, which stresses internal and physiological factors, rather than
external/psychological ones.
- As a neurotransmitter, serotonin is an endogenous chemical released by neurons
to cross the synaptic cleft and allow the transmission of nerve impulses.
- The neurotransmitter serotonin is particularly important in the control of
aggressive behaviour.
Neural Explanations for Aggression
The limbic system and serotonin
Neural refers to the nervous system – the CNS and the PNS. These are part of the
biological explanation for aggression which stresses internal and physiological factors
rather than external/psychological ones. In the aggression topic we will focus on the
roles of the limbic system within the brain and the neurotransmitter serotonin.
The limbic system
The limbic system is subcortical (below the cortex) and therefore deep within the brain
The limbic system has a crucial role to play in emotional behaviour. It includes a number
of different components but the two most important for aggression are the amygdala and
the hippocampus.
The role of the amygdala is to:
1. Identify our emotional state in response to an external stimulus
2. Launch a behaviour (e.g. aggression) which satisfies this emotional state
This is responsible for quickly evaluating the emotional importance of sensory
information and prompting an appropriate response.
The role of the hippocampus is to:
1. Search our LTM for how we responded in similar situations in the past and to
consider the outcome of those responses. Therefore, if we used aggression in a
similar situation in the past and the outcome was not positive, the hippocampus
could brake or check the aggressive impulse from the amygdala.
,This is involved with the formation of long-term memories, and so allows an animal to
compare the conditions of a current threat with similar past experiences. For example,
if an animal had previously been attacked by another animal, the next time they encounter
that animal they are likely to respond either with aggression or fear, whichever is more
appropriate. Impaired hippocampal function prevents the nervous system from putting
things into a relevant and meaningful context, and so may cause the amygdala to respond
inappropriately to sensory stimuli, resulting in aggressive behaviour.
A03
Point Evidence Conclusion
A strength of the neural Many of the studies listed This is a strength of the
explanation is that the below were conducted in neural explanation as it
research adopts a laboratory conditions and suggests that the evidence
scientific approach to are based on the researcher on which it is based has
study and is able to manipulating levels of internal validity.
demonstrate cause and serotonin and observing
effect (for serotonin). and recording the effects
on levels of aggression.
A weakness of the neural Both the limbic system and This is a weakness of the
explanation is that it could serotonin explanations neural explanations as it
be seen as overly could be seen as overly ignores the argument that
deterministic. deterministic as they individuals have free will
suggest that aggressive and choose to act
behaviour is determined aggressively or not. This has
by internal factors that are clear implications for the
beyond our control. criminal justice system; if
an individual’s aggression is
determined by neural
factors, they cannot be
held responsible for their
aggressive behaviour.
Evidence to support the Gospic found that when This supports neural
amygdala’s role in the responders aggressively explanations for aggression
limbic system as part of the rejected an unfair offer as it suggests a link
neural explanation for from the proposer in “The between the
aggression comes from the Ultimatum Game”, fMRI responsiveness of the
work of Gospic. scans of their brains amygdala and aggression.
revealed a fast and
heightened response by
the amygdala.
Evidence to support the Kluver and Bucy found that This supports the
amygdala’s role as part of destroying the amygdala importance of the limbic
, the limbic system / neural of a dominant monkey system as an explanation
explanation for aggression caused it to lose its for aggression as without
comes from the work of dominant position within its amygdala, the monkey
Kluver and Bucy. the hierarchy. no longer responded to
external threats with
aggression.
The Kluver and Bucy study The Kluver and Bucy study The use of NHAs may
may not provide valid data is based on studying non- undermine the usefulness
to support the neural human animals. of the study in terms of the
explanation of aggression. extent to which its findings
can be used to support
neural explanations of
aggression amongst
humans.
Evidence to support the Boccardi et al found that This supports the neural
role of the hippocampus in habitually violent explanation for aggression
the limbic system as part of offenders exhibited as those with hippocampal
the neural explanation for abnormalities of abnormalities were less
aggression comes from hippocampal functioning. able to put sensory
Boccardi et al. information into a valid
and meaningful context,
making a more aggressive
response from the
amygdala more likely.
2nd part of the neural explanation:
- Serotonin
As with the limbic system, serotonin is part of the biological explanation for
aggression, which stresses internal and physiological factors, rather than
external/psychological ones.
- As a neurotransmitter, serotonin is an endogenous chemical released by neurons
to cross the synaptic cleft and allow the transmission of nerve impulses.
- The neurotransmitter serotonin is particularly important in the control of
aggressive behaviour.
