biological explanations of offending behaviour: Genetic and neural

Epigenetics

refers to the material in each cell of the body that acts like a set of 'switches to turn genes on or off.

what are genetic explanations?

The likelihood of behaving in a particular way is determined by a person's genetic make-up, i.e. it is inherited from parents.

neural explanations?

involve areas of the brain and nervous system and the action of chemical messengers in the brain known as neurotransmitters in controlling behaviour.

what is the gene which has been asociated with aggression?

low activity MAOA gene

What did Brunner conduct a study on?

observed 28 male members of a Dutch family who had histories of impulsive and violent criminal behaviours such as rape and attempted murder

what were Brunner’s findings?

analysed the DNA of these men and found they shared a particular gene that led to abnormally low levels of MAOA.

what do the resuts of concordance rates suggest about genetics?

the concordance rates for MZ twins is not 100%, and so this suggests that an interaction between the environment and genetics together produces the outcome of criminality, and so the traditional diathesis-stress model can be used to account for this.

what did Caspi study?

used data from the longitudinal Dunedin study (in New Zealand) that has followed about 1,000 people from when they were babies in the 1970s.

what did the findings of Caspi’s study find?

assessed antisocial behaviour at age 26 and found that 12% of those men with low MAOA genes had experienced maltreatment when they were babies but were responsible for 44% of violent convictions.

what did Raine do?

cited 71 brain imaging studies

what were Raine’s findings?

that murderers, psychopaths and violent individuals have reduced functioning in the pretrontal cortex, the area of the brain that is involved in regulating emotion and controlling moral behaviour in general. Lowered activity in this area is associated with impulsiveness and loss of control.

whta is the limbic system?

This is a set of subcortical structures, such as the thalamus and the amygaala, that are linked to emotion and motivation.

what did Raine find in relation to the limbic system in criminals?

Compared with matched controls, they found abnormal asymmetries in the limbic system of the murderers, especially the amygdala - there was reduced activity on the left and increased activity on the right.

what role does serotonin play in criminals?

suggest that low levels of the neurotransmitter serotonin may predispose individuals to impulsive aggression and criminal behaviour. Low levels mean a lack of inhibition, by the prefrontal cortex, of impulsive aggressive urges. Dopamine hyperactivity may enhance this effect.

what role does noradrenaline play in criminals?

Both very high and very low levels of this neurotransmitter have been associated with aggression, violence and criminality

what are high levels of noradrenaline associated with in criminals?

High levels of noradrenaline are associated with activation of the sympathetic nervous system and the fight-or-flight response, and High levels of noradrenaline are associated with activation of the sympathetic nervous system and the fight-or-flight response, and thus are linked to aggression.

what are low levels of more adrenaline linked with in criminals?

Noradrenaline also helps people react to perceived threats, so low levels would reduce this ability

whats the limitation with using twin studies as a means of investigating the genetic basis of behaviour

such studies assume that the only difference between twins is the amount of genetic information they share. This is an incorrect assumption and would be better addressed through the use of an interactionist approach. For example, the fact that MZ twins are likely to share the same environment as opposed to normal siblings may explain why MZ concordance rates are higher than for normal siblings, despite both sharing 50% of their genes.

what’s a limitation about biology being a determinist explanation?

It can be argued that the genes a person is born with determine later behaviour and so they blame their biology, its not their fault or their responsibility, a deterministic view is at odds with the justice system and societies understanding of responsibility

what’s a problem with cause and effect in the biological explanation?

whether abnormalities in regions of the brain or levels of neurotransmitters are the cause of offending behaviour, the result of it, or actually just an intervening variable. for example, someone who grew up in a violent household or engages in risky behaviours

how has the biological explanation applied to the real world?

methods of treatment.

For example, if low levels of serotonin are, related to increased aggressiveness in criminals, then people in prison could be given diets that would enhance their serotonin levels and hopefully decrease their aggression.

what was the shot sauce study?

pps had option to punish those they believed had taken money from them by using spicy sauce, normal MAOA gene vs MAOA-L, low provocation condition (not a lot of money taken) not significant difference between control and experimental group, high provocation condition aggression increased especially in MAOA-L group

evaluation

• strengths: supporting evidence for the MAOA-L gene Brunner dutch family

• strength: supporting evidence for abnormal neurological structures Raine

• limitations: biological determinism

• limitation: caspi biological pre disposition wasn’t enough

• social sensitivity: labelling individuals as potential criminals