Criminal Behaviour - Biological Explanations

Question 1

1 What does the genetic argument propose?

Answer 1

One or more genes predispose individuals to criminal behaviour

Question 2

1 What genes have been linked to criminality?

Answer 2

Monoamine oxidase A (MAOA)
Cadherin 13 (CDH13)

Question 3

1 What did Brunner et al (1993) find?

Answer 3

Analysed DNA of 28 male members of a Dutch family with history of impulsive and violent behaviours (rape/murder)
Found that the men shared a particular gene which led to abnormally low levels of MAOA (‘warrior gene’)

Question 4

1 Modern understanding?

Answer 4

No longer suggests that one or even a few genes will solely determine behaviour.

Question 5

1 Current thinking?

Answer 5

In terms of an interplay between genes and environment.

Question 6

1 What do epigenetics propose?

Answer 6

Genes are ‘switched’ on or off by epigenomes which have been effected by environmental factors (diathesis-stress model)

Question 7

1 What did Caspi et al (2002) find?

Answer 7

Used data from a longitudinal study that studied about 1000 people from when they were babies in the 1970s.
He assessed antisocial behaviour at age 26 and found that 12% of those men with low MAOA had experienced maltreatment but were responsible for 44% of violent convictions

Question 8

1 What may ‘criminal’ genes cause?

Answer 8

Differences in activity in areas of the brain or differences in key neurotransmitters

Question 9

1 What did Raine et al (2004) find?

Answer 9

Cited 71 brain imaging studies showing that murderers, psychopaths and violent individuals have reduces functioning in the prefrontal cortex (emotion regulating/controlling behaviour/moral behaviour) - associated with impulsiveness and loss of control

Question 10

1 What did Seo et al (2008) find?

Answer 10

Low levels of serotonin may predispose individuals to impulsive aggression and criminal behaviour (this neurotransmitter normally affects prefrontal cortex). Dopamine hyperactivity may enhance this effect.

Question 11

1 Supporting research (twin studies) for inherited criminality?

Answer 11

Raine (1993) - 52% concordance rate for MZ twins compared to 21% for DZ twins.
Suggests a genetic factor in delinquent behaviour

Question 12

1 Methodological issues for twin studies?

Answer 12

Comparing MZ and DZ twins potentially control environment effects.
Evidence that the environments for MZ twin s are more similar than for DZ twins (similar clothing/friends)

Question 13

1 Supporting research (adoption studies) for inherited criminality?

Answer 13

Crowe (1972) - adopted children had a 38% greater risk of having a criminal record if their biological parent was a criminal compared to adopted children who had a 6% risk if their biological parent wasn’t a criminal
Mednick (1987) - found that out of 14000 adoptees, 15% of sons who were adopted into a criminal family went on to be a criminal compared to 20% of those whose biological parents were criminal.

Question 14

1 Inherited criminality partial explanation? Blonigen et al (2005)?

Answer 14

Biological may only account for certain types of crime such as those involving violence and also psychopathy.
Blonigen - found support for a genetic basis for psychopathy looking at over 600 male and female twins.
‘criminal behaviour’ include theft, fraud, drug use, bigamy - genetic explanations fail to explain.

Question 15

2 Research focus?

Answer 15

Most research attention has focussed on a part of the brain called the amygdala

Question 16

2 What is the amygdala?
What role does it play?

Answer 16

Collection of 13 nuclei found in the limbic system in the centre of the brain. it is a highly connected structure with connections to other regions of the brain - significant effect on our mood and behaviour.
Plays a major role in how we assess and respond to environmental threats.

Question 17

2 What did Coccaro et al (2007) find?

Answer 17

Studied people with intermittent explosive disorder (IED) where each ppt viewed images of faces while hav9ing an fMRI scan.
Ppts showed high levels of amygdala activity when they viewed angry faces - overactivity in the amygdala may be responsible for our reactions to angry faces.

Question 18

2 What did Yu Gao et al (2010) propose?
What does a dysfunction mean?

Answer 18

We learn as children to inhibit aggression and antisocial behaviour through fear conditioning - aggressive behaviour leads to punishment
A dysfunction means that a child cannot identify social cues that indicate threat - does not link punishment to aggressive behaviour.

Question 19

2 What did Yu Gao et al (2010) find?

Answer 19

Conducted a longitudinal study where 1795 ppts were tested for fear conditioning at the age of 3. the measure used was physiological arousal in response to a painful noise.
Those who committed crimes at the age of 23 had shown no fear conditioning when they were 3.

Question 20

2 Supporting research (ultimatum game) for amygdala dysfunction?

Answer 20

Gospic (2011) - involves two players (proposer & responder)
- Proposer - offers to split money in a ‘fair’ or ‘unfair’ way.
- Responder - accept- money is split accordingly. Refuse - both get nothing
Rejection is considered as aggressive behaviour.
when ppts rejected unfair offers, amygdala activity was heightened and quicker, shown in fMRI

Question 21

2 Supporting research (amygdala volumes) for amygdala dysfunction?

Answer 21

Pardini (2014) - studies 56 men who had shown aggressive behaviour since childhood, including involvement in serious offences.
Found that high levels of aggression over the 20 year period were associated with lower amygdala volumes - cannot be explained by potential confounding variables or by earlier levels of aggressive behaviour

Question 22

2 Amygdala dysfunction partial explanation? Raine et al (1997)?

Answer 22

Amygdala functions together with orbitofrontal cortex (OFC) - thought to influence self control, regulate impulsive behaviour and inhibit aggression.
Raine - investigated murderers with an overwhelming degree of reactive aggression - they had higher glucose metabolism in their amygdala but abnormally low metabolism in prefrontal cortex.
Dysfunctions in the amygdala may not be enough on their own to account for criminality