bio explanations: genetic & neural

Question 1

what do genetic explanations for crime suggest

Answer 1

would-be offenders inherit a gene/s that predispose them to commit a crime

Question 2

types of genetic explanations

Answer 2

• twin & adoption studies
• candidate genes
• diathesis-stress model

Question 3

twin studies research

Answer 3

karl christiansen 1977

Question 4

describe twin studies research

Answer 4

• 3500+ twin pairs in denmark
• found concordance rates for offender behaviour were 35% in MZ males & 13% for DZ males
• lower for females
• all twins born 1880-1910 in region of denmark
• offender behaviour checked against danish police records

Question 5

what does the twin studies data suggest

Answer 5

not just behaviour inherited but underlying predisposing traits

Question 6

MZ twins

Answer 6

monozygotic = identical

Question 7

DZ twins

Answer 7

dizygotic = non-identical

Question 8

adoption research

Answer 8

raymond crowe 1972

Question 9

describe adoption research

Answer 9

• found adopted children with biological mother who had criminal record = 50% risk of having criminal record by 18
• compared to 5% risk for adopted children whose biological mother doesn’t have criminal record

Question 10

candidate genes research

Answer 10

tiihonen et al. 2015

Question 11

describe candidate genes research

Answer 11

• genetic analysis of ~800 finnish offenders
• two genes (MAOA & CDH13) associated with voilent crime
• MAOA gene regulates seretonin & linked to agressive behaviour
• CDH13 gene linked to substance abuse & attention deficit hyperactivity disorder (ADHD)
• found 5-10% of all voilent crime in finland attributable to MAOA & CDH13 genotypes

Question 12

describe diathesis-stress model

Answer 12

• genetic influence on offending partly moderated by effects of environment
• tendency towards offending behaviour may arise from combination of genetic predisposition & biological/psychological trigger
• eg. raised in dysfunctional environment, criminal role models

Question 13

idea for neural explanations

Answer 13

neural differences in brains of offenders & non-offenders

Question 14

where is much of the evidence for neural explanations from

Answer 14

antisocial personality disorder (APD)
= reduced emotional responses, lack of empathy & condition which characterises many convicted offenders

Question 15

(neural) research on prefrontal cortex

Answer 15

adrian raine
(lot of studies on APD brain)

Question 16

(neural) describe research on prefrontal cortex

Answer 16

• reported there’s several dozen brain-imaging techniques showing individuals with APD have reduced activity in prefrontal cortex
• prefrontal cortex = regulates emotional behaviour
• raine & colleagues (2000) found 11% reduction in grey matter in prefrontal cortex of those with APD vs. controls

Question 17

(neural) research on mirror neurons

Answer 17

christian keysers 2011

Question 18

(neural) describe research on mirror neurons

Answer 18

= recent research suggests those with APD can experience empathy but more sporadically

research (keysers 2011)
- when offenders asked to empathise = empathy reaction (controlled by mirror neurons) activate
- suggests APD individuals not totally without empathy but may have neural ‘switch’ to turn on/off

Question 19

genetic AO3: (-) issues with twin evidence

Answer 19

P: a limitation of using twin studies for genetic evidence is the assumption of equal environments

E: twins being studied may not have experienced constant environmental factors growing up. this ‘shared environment assumption’ may apply more to MZ twins than DZ twins as MZ twins appear identical so people (especially parents) will treat them more similarly which impacts their behaviour

T: thus, higher concordance rates for MZ twins may be due to their similar treatment compared to DZ twins

Question 20

genetic AO3: (+) support for diathesis-stress

Answer 20

P: research support for diathesis-stress model

E: study of 13,000 danish adoptees by mednick et al. (1984) where neither biological/adoptive parents had convictions, percentage of adoptees which did was 13.5% (quite high). this rose to 20% when either of biological parents had convictions & 24.5% when both adoptive/biological parents had convictions

T: shows genetic inheritance plays role in offending but environmental factors clearly influence also which provides support for this model

Question 21

EXTRA genetic AO3: (+/-) nature v. nurture

Answer 21

(+) it’s presumed adoption studies (eg. mednick et al.) are good way of separating nature v. nurture & if crime has genetic component, then adopted child should still experience influence of biological parent (without living with them)

(-) however, many adoptions occur when they’re older & so, spend several years with biological parents. also, many adoptees encouraged to maintain contact with biological families so exert environmental influence

Question 22

neural AO3: (+) brain evidence

Answer 22

P: support for link between crime & frontal lobe

E: kandel & freed (1989) reviewed evidence of frontal lobe damage (incl. prefrontal cortex) & antisocial behaviour. people with damage often showed impulsive behaviour, emotional instability & inability to learn from mistakes. frontal lobe associated with planning behaviour

T: supports idea that brain damage may be causal factor in offending behaviour

Question 23

neural AO3: (-) intervening variables

Answer 23

P: link between neural differences & APD is complex

E: other factors may contribute to APD & thus, offending. farrington et al. (2006) studied group of men who scored high on psychopathy (APD). they had experienced various risk factors in childhood eg. raised by convicted parent, physically neglected etc. it could be argued that these early experiences caused APD & some of neural differences associated with it eg. reduced activity in frontal lobe from trauma (rauch et al. 2006)

T: suggests relationship between neural differences, APD & offending is complex as may be many intervening variables which impact it

Question 24

EXTRA neural AO3: (+/-) biological determinism

Answer 24

• biological approach suggests offending behaviour determined by genetic/neural factors which aren’t controlled by individual. thus, they shouldn’t be held responsible for crime.
• however, our justice system is based on notion that we all have responsibility for our actions. only in extreme circumstances (eg. mental disorder) is individual judged to lack responsibility. the identification of possible biological precursors to crime complicates this principle