Forensics - Biological explanations for offending - genetic and neural

Question 1

What did Cesare Lombroso believe?

Answer 1

He believed that certain physical characteristics were more common in criminals than in non-criminals; a type of positivist criminology.

Question 2

What is positivist criminology?

Answer 2

Positive criminology states that there is no free will involved in the committing of a crime - behaviours are a result of certain predetermined physical or mental features.

Question 3

What physical characteristics did Lombroso discover criminals were more likely to have? What are these known as ?

Answer 3

Strong jaw, heavy brow, sloping shoulders, large/lobeless ears, high defined cheekbones, long arms relative to the body, flat nose, and drooping eyelids.

These are known as atavistic features

Question 4

What link did Lombroso make?

Answer 4

He linked the idea that primitive/atavistic physical features were likely to result in primitive/ atavistic instincts. From these instincts, criminal behaviours could develop.
These primitive instincts survived evolutionary natural selection therefore, criminals were ‘genetic throwbacks’ to an earlier time.

Question 5

What are the strengths of linking physical characteristics to crime?

Answer 5

+ It was the first time biology was emphasised in the explanation of criminal behaviour.
+ Lombroso tried to explain criminal acts from many factors and how they interact such as , psychological, biological and social factors. This was influential in later theories of criminology.

Question 6

What are the limitations of linking physical characteristics and crime?

Answer 6

• There was no control group, Lombroso did not compare the atavistic features of the criminal group to a non-criminal group, meaning the AF may not be unique only to criminals, but could be found in the whole populations, regardless of criminality.
• Due to a lack of technology, Lombroso could only focus on the physical features - there could be chromosomal/genetic abnormalities or psychological disorders that could have been factors.

Question 7

What are the three main pieces of evidence for the genetic explanation of criminality?

Answer 7

Adoption studies, genetic influences on aggression and extra Y chromosome studies.

Question 8

What do adoption studies examine?

Answer 8

They examine concordance rates of criminal activity.
Concordance = if one person shows criminal behaviours, the likelihood that another person will.

Question 9

In the case of adoption studies, who is concordance measured between?

Answer 9

The adopted child and adoptive parents
The adopted child and genetic/biological parents

Question 10

What have adoption studies found out about concordance rates and criminality?

Answer 10

They have found that there is a higher concordance rate of criminal activity between the adopted children and their biological parents.

This demonstrates strong evidence of the role of genetics in criminality

Question 11

What is an example of an adoption study?

Answer 11

Mednick et al (1984) - studies criminal behaviour in adopted children

Question 12

What was Mednick’s method?

Answer 12

14,427 Danish adopted children were analysed according to concordance.

The concordance rates of criminality were compared between:
The adopted children and their adopted parents.
The adopted children and their biological parents.

Question 13

What is the conclusion of Mednick’s study?

Answer 13

He concluded that there is a genetic link of criminality.
However, overall the concordance rates are low, meaning that it is likely to be other factors that lead to criminality.

Question 14

What are the strengths of Mednick’s study?

Answer 14

+ Adoption studies are important in the nature vs nurture debate as they can separate out the genetic and environmental influences. Therefore, this is a powerful study.
+ Large sample size was very large, increasing the validity of the results

Question 15

What are the weaknesses of Mednick’s study?

Answer 15

• The study only looked at criminal convictions, not at crimes committed.
• People could have committed crimes and not been convicted. This could cause different results.

Question 16

What could higher levels of aggression lead to?

Answer 16

Could lead to criminal activity

Question 17

What did Christiansen’s twin study find?

Answer 17

Male identical twins had 35% concordance for criminality
Whereas male non-identical twins had only a 12% concordancence rates

Female identical = 21%
Female non-identical = 8%

Question 18

What did Jacobs et al find relating to extra Y chromosomes?

Answer 18

By examining a prison population, Jacobs et al. (1965) found that there was a higher percentage of prisoners with the atypical chromosome pattern (XYY) compared to non-prisoner population.

• Extra Y chromosome could be linked to increased testosterone production and increased violent behaviour

Question 19

What could the chromosomal pattern XYY result in?

Answer 19

Hyperactivity
Increased impulsivity
Lower IQ

Question 20

Raine et al conducted a study to examine the link between brain abnormalities and criminal behaviour. What was their method?

Answer 20

PET scans create 3D images of processes that occur within the brain.
PET scans detect differences in glucose metabolism, an important process of neuron conduction.
- Raine scanned 41 murderers and 41 control participants
- The murderers had plead not guilty by reason of insanity

Question 21

What were the results of Raine’s study?

Answer 21

There were differences in glucose metabolism in three areas of the brain:
- Prefrontal cortex
- Superior parietal gyrus
- The corpus callosum
(limbic system)
These three areas had reduced glucose metabolism in the murderers as compared to the controls
There was also asymmetric activity in the two hemispheres in the murderers.

Overall, some brain processes were dysfunctional in the murderers.

Question 22

What were the conclusions of Raine et al’s study?

Answer 22

Raine found evidence of neural differences in murderers compared to controls.
The evidence supports a link between brain dysfunction and violent criminal activity like murder.

Question 23

What is a strength of Raine’s study?

Answer 23

+ The researchers used a control group who were matched on age and sex, increasing the validity of the results.

Question 24

What are limitations of Raine’s study?

Answer 24

• Correlation between brain dysfunction and violent behaviour, despite a causal relationship, cannot necessarily be concluded. This is because the researchers could not randomly assign the participants into the murderer group and the control group.
• To study the causality of brain dysfunction on criminal behaviour, a longitudinal study would have to be done.

Question 25

What are the strengths of the biological explanation of criminal behaviour?

Answer 25

+ Scientifically tested = makes theories more reliable

Question 26

What are the weaknesses of the biological explanation of criminal behaviour?

Answer 26

• Cannot account for 100% of criminal behaviour (think of concordance rates)
• Inherited emotional instability or mental illness could indirectly result in criminal behaviour instead of genetics.
• too reductionist and too deterministic

Question 27

What are neural explanations?

Answer 27

They consider how structures of the brain maybe different in chemicals as well as there being differences in neurotransmitter levels.

Question 28

What did Keysers et al find?

Answer 28

Found that criminals appear to have a ‘neural switch’ why they can use to turn their capacities for empathy on or off. This may explain why criminals lack empathy towards their victims.

Question 29

What support is there for the use of a diathesis-stress model in explaining criminality?

Answer 29

Mednick et al (1984)
Siblings adopted separately into different homes tended to be concordant for convictions, especially if they shared biological father also had a record of criminal behaviour . Criminality is only likely to be an outcome if a genetic susceptibility is paired with environmental stressors.

Question 30

Why were Lombroso’s methods criticised ?

Answer 30

He lacked adequate controls , when he studied prisoners he didn’t pay the same kind of attention to non-prisoners . Had he done so, it is likely that he would have found as many non-prisoners with the same characteristics as he found in prisoners. A key study conducted by Goring found there were no differences between 3000 convicts and non-convicts except for the fact that convicts were slightly smaller.

Question 31

Why were Lombroso’s suggests gender biassed?

Answer 31

He believed that women were less evolved than men. They were naturally jealous and insensitive to pain but they were also passive, low in intelligence and had a maternal instinct - all of which neutralised their negative traits and meant they were less likely to be criminals . Those women who did become criminals, has masculine characteristics which were beneficial in a man but in a women created a ‘monster’.

Question 32

What were Mednick’s results?

Answer 32

15% of adopted sons by a criminal family went on to be criminals compared to 20% whose biological parents were criminal , suggesting that inherited genes are a marginally more significant factor.

Question 33

What are the two main candidate genes ?

Answer 33

MAOA and CDH13

Question 34

Who found the role of MAOA and its link to offending behaviour?

Answer 34

Brunner conducted a study on 28 male members of a Dutch family who had histories of impulsive and violent criminal behaviours such as rape and attempted murders. Brunner analysed the DNA of these men and found hey shared a particular gene that led to abnormally low levels of MAOA.

Question 35

Who found the role of CDH13 and its link to offending behaviour?

Answer 35

Recent Finnish study by Tiihonen with 900 offenders found evidence of low MAOA activity and also low activity from the CDH13 gene. They estimated that 5-10% of all violent crime in Finland is due to abnormalities in one of these two genes.

Question 36

What link does the prefrontal cortex have to offending behaviour?

Answer 36

Raine cited 71 brain imaging studies showing murderers , psychopaths and violent individuals have reduced functioning in the prefrontal cortex, the area of the brain that is involved in regulating emotion and controlling moral behaviour in general. Lower activity is associated with impulsiveness and loss of control.

Question 37

What role does the neurotransmitter, serotonin play?

Answer 37

Seo suggests that low levels of serotonin may predispose individuals to impulsive aggression and criminal behaviour, partly because serotonin normally inhibits the prefrontal cortex. Dopamine hyperactivity may enhance this effect.

Question 38

What role does the neurotransmitter, noradrenaline play?

Answer 38

Both very high and very low levels of noradrenaline have been associated with aggression , violence and criminality. High levels of noradrenaline are associated with activation of the sympathetic nervous system and the fight-or-flight response and are therefore linked to aggression. Noradrenaline also helps people to react to perceived threats , so low levels would reduce this ability.

Question 39

NE = Explain difficulty establishing cause and effect in neural explanations

Answer 39

One issue is about 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. Research only highlights a correlation between head injuries and later criminality. It is possible that it is a false relationship, for example, someone who grew up in a violent household might be more likely to suffer head injury. In such a case the link between head injury and offending behaviour could be because of a violent childhood.

Question 40

What real world application is there for neural explanations?

Answer 40

Can lead to possible methods of treatment. If low levels of serotonin cause increased aggressiveness in criminals , then people in prison could be given diets that would enhance their serotonin levels and hopefully lower their aggression.

Question 41

Explain why neural explanations may be related to aggression rather than offending

Answer 41

Research on neurotransmitters often relies on studies of animals. In such cases it is not criminality that is being studied but aggressiveness, as is also the case in many of the human studies. This undermines the potential relevance of such information for understanding offending behaviour.