Psychobiological Theories

Constitutional Theories  Do criminals look different to everyone else? Sheldon believed that criminals have a specific body shape or physique that accompanies personality type that makes them different from other people. Studied a large sample of males in a rehabilitation institution rating their body types and he produced a typology as a result.

Which one do you think would be labelled a criminal?

Ectomorphic Ectomorphs body types: Thin Fragile Flat chested Delicate build Young appearance Tall Lightly muscled Large brain Stoop-shouldered Associate Personality Traits: Self-conscious Preference for privacy Introverted Inhibited Socially anxious Artistic Mentally intense Emotionally restrained Solitary Thin and bony ectomorphs: introverted and restrained.

Endomorphic Endomorphic Body Type: Soft body Underdeveloped muscles Round shaped Over-developed digestive system Associated Personality Traits: Love of food Tolerant Even display of emotions Love of comfort Sociable Good humoured Relaxed Need for affection Enjoy the company of others Large and heavy endomorphs: sociable and relaxed.

Mesomorphic Mesomorphic Body Type: Hard muscular body Overly mature appearance Rectangular shaped Thick skin Upright posture Associated Personality Traits: Adventurous Aggressive Desire for power and dominance Courageous Indifferent to what others think or want Assertive, bold Zest for physical activity Competitive Love for risk and chance High pain tolerance Callous Careless of others’ feelings Broad and muscular mesomorphs: aggressive and adventurous

Can you think of any problems with Sheldon’s work? Criticised on methodological and subjective grounds as he rated his subjects’ body types himself! Criticised on methodological and subjective grounds as he rated his subjects’ body types himself!

Genetics  Lombroso: 19 TH Century Italian hospital doctor, believed:  Criminals were genetically different to non-criminals and this could be seen in their faces.  Criminality could be acquired by direct contact with other criminals: direct heredity  A third of offenders are born criminals.

Genetics Suggested that criminals display a range of physical characteristics which reveal clues that they are throwbacks to more primitive times.

Genetics  At the same time it was also a belief of some that criminality was related to intelligence.  Goring: after studying 3000 English convicts found them to be less intelligent than would be expected. ‹

Evaluation of Lombroso’s Work Did not use a control group of non-criminals Highly unrepresentative sample: criminals who were mentally disturbed or had chromosomal abnormities. Lombroso known as the father of modern criminology suggesting great importance to his work.

Recent Research  Focused on: FamilyAdoptees Twins

Family Studies  The closer the biological relationship: the higher the genetic similarity.  If criminality is inherited: criminal families should produce criminal children.  Osborn & West (1940): 40% of sons of criminal fathers were criminals themselves. 13% sons were criminal from non-criminal fathers.

Family Studies  N.B.:  The study only implies that a relationship exists between criminality and the closeness of a relationship. It is not possible to infer causation.  It could be that environmental variables such as poor housing and unemployment caused both parent and child to commit crimes.  It may be possible that social and psychological factors within the family are responsible for the transmission of criminal values.

Twin Studies  Monozygotic twins (MZ): share identical genetic makeup  Dizygotic twins (DZ): non-identical  If crime is inherited: MZ twins should have a higher concordance rate for crime than DZ twins.  Concordance = a percentage that expresses the degree to which a related pair of participants exhibit the same behaviour.

Twin Studies RESEARCHER MZs CONCORDANCE (%) DZs CONCORDANCE (%) Lange (1929) 7712 Legras (1932) 1000 Yoshimasu (1965) 500 Chriastiansen (1977) 3212 SUMMARY OF THE FINDINGS: What does this table show? Higher rate of concordance for MZ twins than DZ twins for criminal behaviour.

Evaluation of Twin Studies  Often difficult to obtain samples of twins especially MZ. Therefore sample sizes tend to be small and caution has to be taken when generalising.  Studies were carried out years ago when distinction between MZ and DZ was based on appearance. Difficult to tell if set is MZ or DZ: problems with the methodology.  The table showed concordance rates for MZ decrease in later studies: main reason is that the later studies had the means to assess the zygocity to a higher degree of accuracy.  MZ twins share more than genes. Tend to form closer relationships than DZ twins and therefore could display similar behaviour including criminal behaviour.  There does however, appear to be evidence to suggest a link between genes and criminality.

Adoption Studies  Does the child follow the biological or adopted parent? Nature-Nurture Debate! Crowe (1974): 50% of adoptees convicted of a criminal offence had mothers with a criminal record compared to a control group of 5% of adoptees born to mothers with a non-criminal record. Crowe (1974): 50% of adoptees convicted of a criminal offence had mothers with a criminal record compared to a control group of 5% of adoptees born to mothers with a non-criminal record.

Adoption Studies Adoptive Parents CriminalNon-Criminal Criminal24.5%14.7% Non-Criminal20%13.5% Biological Parents Shows that having a biological parent who is criminal does lead to higher criminal rate for male adoptees. Higher percentage when both biological and adoptive parents are criminal. Table showing the % of adoptees with criminal records according to criminality of parents:

Evaluation of Adoption Studies  Studies only looked at two variables: criminal behaviour and the relationship with parent/s.  Bohman (1995) showed that the environment has most effect on those children who might have already been genetically predisposed towards criminal behaviour. Adoptive Parents Criminal Record Adoptive Parents No criminal record Biological Parents Criminal Record 40%12% Biological Parents No criminal record 7%3%

Evaluation of Adoption Studies  Adoptive families are often selected on basis of their similarity to the original family.  Sample sizes end to be small and there are contamination effects as children have been adopted at different ages.  Overall results from family, twin and adoption studies suggest heritable factors increase the likelihood of criminal behaviour

Biochemical/Neurological Theories  Research suggested that the development of criminal behaviour may be related to neurological and biochemical factors.  Firstly we will look at the neurological factors.  The central nervous system (CNS) consists of the brain and spinal cord. Studies of the CNS involve the measurement of brain activity.

Biochemical/Neurological Theories Electroencephalogram (EEG): measures electrical activity of the cortex of the brain. Electroencephalogram (EEG): measures electrical activity of the cortex of the brain. Generally, studies have not shown any long term relationship between EEG abnormality and any future criminal behaviour. Problems with this type of research: EEG recordings can be affected by technical factors e.g. position of electrodes. Previous injury can affect recording. Need to consider contribution of social and economic factors. Lack of baseline measurement. Researchers have compared EEG recordings of matched criminal and non-criminal samples

Biochemical/Neurological Theories Research examined levels of neurotransmitters: electrochemical messengers that are responsible for relaying information throughout the nervous system. Serotonin (main neurotransmitter) acts to inhibit behavioural responses and is thought to play a role in aggressive and violent behaviour. Studies suggest that low levels of serotonin is associated with violence. Fishbein (1990) criticises this research:  Not all studies define violence in the same way  Nor realistic to isolate serotonin and study it in relation to aggression: therefore reductionist approach  Neurotransmitters affected by other drugs such as alcohol.

Biochemical/Neurological Theories Hormones: chemical messengers which are released by certain glands in the body also have strong influence on behaviour. Focus on the relationship between male testosterone and criminal behaviour. Findings suggest a link between testosterone and criminal behaviour:  Delinquency and aggression increase during puberty  Makes are said to be more violent than females N.B. high levels of testosterone have been found in males with no record of violent behaviour and criminal behaviour does not necessarily involve violence.

Personality Theory Eysenck (1959) defined two dimensions of personality:  Extravert (E) and Neuroticism (N) Each dimension is perceived as a continuum with most people falling in the middle of the range.

Personality Theory  Extraversion ranges from high: extravert to low: introvert.  Neuroticism ranges from high: neurotic to low: stable. The extravert is cortically under-aroused and as a result needs to constantly seek out stimulation to keep cortical arousal at an optimal level: The extravert is cortically under-aroused and as a result needs to constantly seek out stimulation to keep cortical arousal at an optimal level: impulsive by nature, seek excitement, enjoy company, lively parties and are optimistic. The introvert is cortically over-aroused, avoid stimulation to keep arousal levels comfortable: reserved, cautious, dislike change and noisy gatherings.

Personality Theory  Neuroticism (emotionality) related to the functioning of the Autonomic Nervous System (ANS).  Individuals that score high on the neuroticism scale have and excitable ANS: causes strong reactions to painful or aversive stimuli and neurotic tend to be moody and anxious.  Individuals that score low on the neuroticism scale: calm and even tempered even under times of stress.

Personality Theory  Link been found between conditionality and neuroticism and extraversion.  Individuals high on N: condition less easily  Individuals low on N: efficient conditioning  Extroverts less easy to condition than introverts  Psychotic: lack of feeling, aggression and preference for solitude. RECAP: STABLE INTROVERTS CONDITION BEST NEUROTIC EXTRAVERTS CONDITION POORLY

Personality Theory Eysenck suggests it is through conditioning that children learn to control anti-social behaviour thought the development of a conscience. E.G. Money Child takes (anti-social behaviour) Parental anger links Child experiences pain and anger of parents End result Socialised child

Personality Theory Eysenck believed that the ease and speed of conditioning i.e. socialisation depends on the child’s personality in terms of E and N.  He predicted that individuals with high E and high N should be well represented in offender groups.  High E, Low N and Low E, High N would be expected to be represented fairly in both offender and non-offender groups.  Low E and Low N should be under-represented in offender groups.  Individuals with strong anti-social tendencies tend to be high on P, E, and N.

Personality Theory Evidence to support Eysenck’s theory. McGurk and Dougall (1981):  Found high levels of P, E, and N only in delinquent samples.  Low E and low N only found in the non- delinquent group of the research.  Even though there is support for Eysencks theory of relationship between personality and crime it does not explain all crime and is not applicable to all offenders.

Evaluation of biological theories of crime! ACTIVITY!  Think in pairs of two positives and two negatives of the biological theory of crime!

Evaluation of biological theories of crime! They draw attention to the importance of biology, particularly genetics, in influencing behaviour They take account of personality differences that might exist from birth, such as impulsiveness and a desire for excitement They help us understand how genetic potential can lead to such problems such as poor achievement in school and inadequate socialisation, which in turn may result in criminality They are simplistic theories, taking account of only one factor i.e. biology. It is very unlikely that criminal behaviour can be reduced to a biological explanation alone. They ignore or underestimate the social causes of crime such as antisocial role models and an emotionally deprived childhood

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