Neural Mechanisms - Biochemistry

Question 1

High levels of what, and low levels of what have been linked to aggressive behaviour? What else

Answer 1

High levels of dopamine and low levels of serotonin have been linked to aggressive behaviour.

Abnormally high levels of serotonin also linked to aggression too.

Levels deviate and fall outside on a range, with serotonin.

Question 2

Are serotonin levels that are linked to aggression fixed?

Answer 2

No, levels can deviate and fall outside of a range, with serotonin.

Question 3

What is serotonin? What does it do?

Answer 3

A NT that has a widespread inhibitory effect on the brain.

It slows down and dampens neuronal activity.

Question 4

What are normal levels of serotonin in the OFC linked with?

Answer 4

Reduced firing of neurons, and this is associated with a greater degree of behavioural self-control.

Question 5

Outline the study of Denson et al in 2012. What supports this?

Answer 5

Stated that decreased serotonin may well disturb the OFC, reducing self-control and leading to an increase in impulsive behaviour including aggression.

This is supported by patients with OCD, as they experience a reduction in serotonin which also leads to impulsive behaviour.

Question 6

Outline the study completed by Bond in 2005.

(Children and adults)

Answer 6

Stated that lower levels of serotonin are found in children & adults prone to violence.

Question 7

Outline the study completed by Bond in 2005.

(Milgram type)

Answer 7

Stated that lowering serotonin levels in a lab increases a response to aversive events and willingness to deliver supposed electric shocks.

This shows that lower levels of serotonin are more likely to trigger aggressive behaviour.

Question 8

Outline the study completed by Mann in 1990. Was this seen in female studies?

Answer 8

Stated that when levels of serotonin are artificially reduced by a drug, participants responses to a ‘hostility and aggression’ questionnaire were increased.

This was not seen in female studies though.

Question 9

Outline the study completed by Cherek et al in 1996.

Answer 9

Stated that when men are given serotonin boosts it causes a calming effect and a lowering of aggressive responses.

Question 10

Outline the study completed by Crockett and Passamonti et al in 2011.

Answer 10

Stated that an individual with low serotonin has less control over their emotional response, and this can lead to aggression.

Question 11

Outline the study completed by Berman et al in 2009.

Answer 11

Gave PPs either a placebo or paroxetine (a drug which enhances serotonin activity).

PPs then took part in a laboratory based game in which electric shocks of varying intensity were given or received in response to provocation.

The group that took paroxetine consistently gave fewer and less intense electric shocks compared to the placebo group.

However, this was only true of PPs who had no history of aggressive behaviour.

Nevertheless, this study is useful evidence of a link between serotonin function and aggression that goes beyond correlational findings.

Question 12

Outline the study completed by Raleigh et al in 1991.

Answer 12

Provide support for the importance of serotonin in aggressive behaviour.

Studied vervet monkeys.

Those monkeys fed on diets high in tryptophan (which increases serotonin levels in the brain) exhibited lower levels of aggression.

Those fed on diets low in tryptophan exhibited increased levels of aggression.

Question 13

Outline the study completed by Popova in 1991.

Answer 13

Applied knowledge of serotonin by selectively breeding more docile animals for domestication.

This allowed for the gain of higher levels of brain concentrations of serotonin over generations.

Question 14

Outline the study completed by Ferrari et al in 2003.

Answer 14

Conducted an experiment that forced rats to fight at exactly the same time every day for 10 days.

On the 11th day the rats were not allowed to fight and the level of serotonin and dopamine was measured in their brain.

It was found that the rat’s serotonin levels had decreased and their levels of dopamine had increased.

This demonstrates that consistent aggressive behaviour can alter brain chemistry.

Question 15

What is dopamine?

Answer 15

The chemical that mediates pleasure in the brain.

Question 16

When is dopamine released?

Answer 16

It is released during pleasurable situations and stimulates one to seek out the pleasurable activity or occupation.

Question 17

Give 3 examples of stimulants of dopamine release in the brain. What areas are influenced by dopamine the most?

Answer 17

Food.

Sex.

Several drugs.

Question 18

What areas are influenced by dopamine the most?

Answer 18

The nucleus accumbens and prefrontal cortex.

Question 19

Outline the study completed by Lavine in 1997.

Answer 19

Stated that an increase of dopamine activity via use of amphetamines has been associated with increases in aggressive behaviour.

Question 20

Outline the study completed by Buitlaar in 2003.

Answer 20

Stated that antipsychotics, which have been shown to reduce dopamine activity in the brain, have been shown to reduce aggressive behaviour in violent delinquents.

Question 21

Outline ‘much research involves non-human animals’.

(As an evaluation of biochemistry associated as a neural mechanisms of aggression)

Answer 21

Extrapolations are weak as many animals do not share the same brain structures as humans.

Many ethical considerations when using animals in research, researchers must respect the animals’ worth regardless of utility value.

Animal studies do not reliably predict human outcomes, they are an unrepresentative sample.

Question 22

Outline ‘using biochemistry is biologically deterministic’.

(As an evaluation of biochemistry associated as a neural mechanisms of aggression)

Answer 22

There is a focus on nature, more than nurture, so doesn’t necessarily consider other human characteristics.

Presents aggression in a negative way, as it assumes all human behaviour is lawful and fixed.

Lacks free will and doesn’t consider the impacts of individual differences that can shape one’s own outcomes.

Question 23

Outline ‘implications on the legal system’.

(As an evaluation of biochemistry associated as a neural mechanisms of aggression)

Answer 23

Stephen Mobley: Convicted murderer executed 1991, his attorneys stated he was genetically predisposed to seeking violent solutions to conflict. The murder was apparently not results of evil free will, but of tragic consequences of gene disposition.

Abdelmalek Bayout: Stabbed and killed a man, received a sentenced of 9 years and 2 months. An appeal court judge in Italy cut Bayout’s sentence by a year after finding out he had gene variants linked to aggression.

Undermines the legal system, as people should be held responsible for their actions.

More people are likely to commit and appeal crimes if there is a chance of getting away with crimes. There could be greater economic implications in government spending if more criminals appeal for gene tests.

Question 24

Outline ‘drugs’.

(As an evaluation of biochemistry associated as a neural mechanisms of aggression)

Answer 24

Drugs can have other effects on the body. E.g. OCD - antipsychotics have a dopamine lowering effect.

Significantly reductionist, as it breaks complex behaviours into small constituent parts to then be treated.

Not holistic, the entire human should be studied in order for a treatment to be chosen. This is supported by the humanistic approach.

Question 25

Outline ‘dopamine and serotonin in other behaviours/ conditions’.

(As an evaluation of biochemistry associated as a neural mechanisms of aggression)

Answer 25

Disorders such as OCD: antipsychotics, reduce levels of dopamine in order to treat OCD.