An integrative look at criminal behaviour

2.3 The biological level of analysis

Criminal behaviour

• Name programmes you know that are about solving crime…

• And some of them that integrate medical and psychological information into the episodes…

Category: Crime television series

• CSI (Miami, NY…)• Wire in the Blood• Criminal Minds• Midsomer Murders• Detective Linley• Miss Marple• Rebus• Bones• Dexter• In this category: 597

The nature of crime

• We are both appalled and fascinated by the nature of crime

• We also want to prevent and solve crime, right?• So what makes people turn to criminal

behaviour? Born a criminal? Bad environment? In this chapter we are going to investigate criminal behaviour from the biological level of analysis and come back to use the cognitive and sociocultural when we have studied them.

What makes one turn to criminal behaviour?

• Early theorists believed that there were “criminal types” (and some still do!) that they came from certain ethnic groups, had certain physical characteristics (strong jawline, high cheekbone, large ears, extra fingers or toes)

• Today, psychologists recognize that the origins of criminal behaviour are complex, resulting of a combination of risk factors – both biological and environmental factors – which interact.

• The more of these factors – the more likely the individual is to engage in criminal behaviour

The biological level of analysis

• Genetics• Brain• Neurotransmitters• Hormones

Are some born to be criminals?

• No, however Biological factors can contribute to criminality

Genetics

• Twin studies• Christiansen 1977 studied 3586 sets of twins• Results indicate that there may be some

genetic factors: concordance rate: 35% in MZ males, 13% DZ males

• 21 % MZ females, 8% DZ women• Limitations: ?

Limitations

• Share same environment• MZ twins Get treated more similar than DZ

twins

Adoption studies

• Hutchings and Mednick (1975)• Results: found that if both the biological and

adoptive fathers had criminal records , 36,2 % of sons had a criminal record

• If only the biological father had it, it dropped to 21,4 %

• If only the adoptive father, it fell to 11,5%• When none of the fathers had a record, 10,5%

of sons had one

Adoption studies

• This study shows the importance of environmental factors in combination with genetic factors

Limitations:1. Similar homes2. Some children are several years when they

are adopted

Limitations with genetic factors

1. What is a “crime gene” – and which crime does it reflect…tax crime? Drugs? Murder?

2. Can’t explain why it change over time in a person’s life – peak in their 20s and declining after 30

The brain

• Blair et al (1999) examined brains of convicted psychopaths using PET scans that revealed impairment of the pathways between amygdala and the frontal lobe.

• Amygdala – responsible for emotional responses• Frontal lobe - decision making

The Brain

• The theory is that due to this impairment, they have a difficulty in moderating their emotional reactions, which in turn has an effect on social relationships which leads to undeveloped empathy, undeveloped feeling of guilt and that they act more impulsively

The brain

• The frontal brain hypothesis – the theory behind that due to a malfunctioning relationship between frontal cortex and the limbic system (amygdala is part of the limbic system) could cause criminal behaviour

• Does not explain all criminal behaviour

Raine et al (1997)

Read Raine et al (1997) study on brain abnormalities in murderers indicated by positron emission tomography (PET) and write a summary of it. Use max 200 words, Include: the aim, method and results.

Neurochemical imbalances

Neurotransmitters and hormones• Seems to best explain the significant gender

difference with regard to crime• 2004 US, 90,1 % arrested murderers were

male, 82,1% arrested for violent crime were male

Neurochemical imbalances

Two explanations for this is: • Low levels of serotonin (which men usually

have) is linked to antisocial and impulsive behaviour

• Violent criminals have higher doses of testosterone than non-aggressive criminals

• Limitations: correlational studies = no cause and effect

• Unsure if chemical imbalances are due to genetic factors or environmental

Nature of crime

• Biological level of analysis can’t on its own give the full explanation of the nature of crime, to be continued…

• But what if…• (TOK: ethics on p. 63)