Forensic psychology: biological explanation (genetic)

Question 1

how are genetics used to explain why people commit crimes?

Answer 1

.twin studies
.candidate genes
.diathesis stress model

Question 2

who conducted research that supported the genetic biological by using twin studies?

Answer 2

Johannes Lange (1930)

Question 3

what did johannes lange do (1930) do?

Answer 3

.investigate 13 identical (MZ) twins and 17 non-identical (DZ) twins
.one of the twins in each pair had served time in prison

Question 4

what did johannes Lange find?

Answer 4

.10 of the MZ twins had a co-twin who was also in prison
.2 of the DZ twins had a co-twin who was also in prison

Question 5

who conducted further research supporting twin studies?

Answer 5

Christianson (1977)

Question 6

what did christianson do?

Answer 6

.studied 3500 twin pairs in Denmark

Question 7

what did christianson find?

Answer 7

.found a concordance rate for offender behaviour of 35% for identical (MZ) twins and 13% for non-identical (DZ) twins

Question 8

what does each research about twin studies tell us about the genetic influence of offender behaviour?

Answer 8

.the more similar genes you have with someone or the more genes you share you are more likely to develop behaviour they also have eg:criminality

Question 9

what are candidate genes?

Answer 9

.genes that create a vulnerability to a particular disorder or illness (increases the likelihood)

Question 10

who conducted candidate gene research to support the influence of genes on criminality?

Answer 10

Tiihonen et al (2014)

Question 11

what did tiihonen et al (2014) do?

Answer 11

.he examined 2 genes linked to violent crimes
.looked at 800 offenders

Question 12

which 2 genes did tiihonen et al (2014) look at?

Answer 12

.MAOA gene (controls serotonin and dopamine in the brain) -linked to violence
.CDH13 gene (linked to substance abuse and attention deficit disorder)

Question 13

what did tiihonen et al (2014) find?

Answer 13

.individuals with this high-risk combination are 13 times more likely to have a history of violent behaviour

Question 14

how does the diathesis stress model support the influence of genetics in offenders

Answer 14

.genes predispose someone to have criminal behaviour however the behaviour will only be shown if there is a precipitating factor in the environment.

Question 15

who conducted diathesis stress model research to support the influence of genetics on criminality?

Answer 15

Capsi et al (2002)

Question 16

what did capsi et al (2002) do?

Answer 16

studied 500 male children

Question 17

what did capsi et al (2002) find?

Answer 17

.those with low levels of MAOA were more likely to exhibit antisocial behaviour BUT only if they had been maltreated as children

Question 18

how does capsi’s et al (2002) research support the research of diathesis stress model in the influence of genetics in criminality?

Answer 18

.because it shows that the gene that predisposes someone to act in a certain way however a stressor in the environment triggers the gene so if there is no stressor nor no gene, the person won’t offend.
.criminal behaviour may be due to a genetic disposition and psychological trigger.

Question 19

what are some negatives to the genetic explanation of criminality?

Answer 19

.hard to separate nature and nurture -the evidence from twin studies may not of been from the similarity in genes but because of the environment -twins are brought up in the same or similar environment more often than not so it may be the environment that’s causing high concordance rates.

Question 20

what are some positives to the genetic explanation of criminality?

Answer 20

.less reductionist -as it acknowledges the environment as a potential factor (diathesis stress model)
-capsi et al (2002) said the males with low levels of MAOA gene were more likely to commit crime BUT only if they had been maltreated as a child