03. Brain and Aggression Flashcards
What is aggression?
-Behaviour that is intended to cause injury, can be psychological as well as physical.
-In animals, aggression is often directed at establishing and maintaining dominance, or acquiring resources (survival advantage).
Describe the structure of the amygdala in relation to aggression.
-The key structure involved in aggression is the amygdala.
-The reactivity of the amygdala in humans is proven to be an important predictor of aggressive behaviour.
-If the amygdala is impaired emotional behaviour is not regulated and emotions like remorse or guilt may not be processed or emotions like fear may not be recognised.
-Can also result in increased levels of irritability and aggression as an appropriate fear response might be impaired.
Describe the structure of the pre-frontal cortex in relation to aggression.
-The OFC is a region of the prefrontal cortex just above the eye sockets.
-It plays an important role in higher cognitive functions such as rational thinking and decision making.
-Involved in self control, impulse regulation and inhibition of aggressive behaviours.
-It’s believed that the left side of the PFC has a role in regulating negative emotions from the amygdala in the limbic system (suggesting they work together).
List the structures of the limbic system.
- Thalamus
- Hippocampus
- Amygdala
- Hypothalamus
What is the function of the limbic system?
Has a central role in how an organism assesses and responds to environmental threats and challenges, therefore its function is for self-preservation. If someone perceives a confrontation, the limbic system might cause an anger response to a perceived threat.
How can neurotransmitters be used to illustrate how brain functions explain aggression?
Serotonin:
-Has widespread function of inhibitory effects on transmission, it slows down neutral activity (inhibitory).
-Normal levels of serotonin in the orbitofrontal cortex (OFC) maintains a reasonable level of behavioural self control.
-Normal levels of serotonin in the OFC maintains a reasonable level of behavioural self control.
-Decreased serotonin in the OFC reduces self control and increases impulsive behaviour which can lead to an increase in aggressive behaviour.
Describe the supporting study by Damasio (1994)
STRUCTURE
-Damasio studied case of Phineas Gage who suffered damage to his pre frontal cortex, resulting in personality change making him irresponsible and aggressive.
-This is a strength as real life case studies indicate brain structure can result in individuals becoming aggressive which increases the plausibility of the explanation of brain structures affecting aggression.
Describe the supporting study by Wong (1997)
STRUCTURE
-Wong et al (1997) used MRI scans with 19 violent male criminals, fund the volume of the amygdala was smaller in violent criminals compared to controls, supporting brain structure as a factor involved in violent offending.
-Considering brain structure as a factor in human aggression could help inform the way violent offenders are perceived by the criminal justice system by including consideration of a person’s predisposition to violence.
Describe the supporting study by Berman (2009)
NEUROTRANSMITTERS AND AGGRESSION
-Berman et al (2009) findings show a direct causation between increased serotonin and lowered aggression as those who had been administered with serotonin acted less aggressively.
-Suggests lower levels of neurotransmitter serotonin can cause aggression.
-This is a strength because this knowledge can be utilised in society to reduce aggression in individuals.
Describe the supporting study by Raine (1997)
FUNCTION OF ORBITOFRONTAL CORTEX
-Raine et al investigated differences in brains of people convicted of murder, who were pleading not guilty on reasons of insanity (NGRI) and a control group.
-Each ppt had a PET scan where they were injected with a radioactive tracer.
-Next they completed a continuous performance activity which would stimulate activity in the prefrontal lobes.
-PET scans were conducted on the participants immediately after the continuous performance task.
-Results showed murderers had reduced glucose metabolism in their left and right orbitofrontal cortex, suggesting that the area is less active than in controls.
-Shows the PFC moderates ability of people to control their impulses including aggression.
Describe the refuting research against Raine’s study in regards to PET scanning techniques.
There are criticisms of the use of PET scanning techniques in the study:
-In Raine’s study PET scanning was done at 10mm slices along the canthomeatal line (an imaginary line from the outer corner of the eye to the middle of the ear).
-This line varies between individuals which makes it hard to locate precisely in ppts.
-Limitation of study as reduces internal validity of the study as it decreases accuracy of findings on impairment to the prefrontal cortex linking to aggressive behaviour.
