Criminal psychology-topic 1.


What makes a criminal?-topic 1


Lombrosso- suggested criminals had similar features. For example, prominent jaw, and large ears. He linked this to the process of natural selection, taking into account evolution. He also took into account social factors, including prisons, which he described as criminal universities.

Sheldon- identified three body types; ectomorphs (thin, fragile, and interverted), mesomorphs (muscular, hard, and aggressive), and endomorphs (fat, soft, and sociable). He proposed that mesomorphs were the most likely to commit criminal offences. However, there was minimal evidence to support this theory.

More modern physiological explanations for criminality focus on genes. However, psychologists are careful to acknowledge that there is not just one gene for crime, but many hereditary factors that contribute. One trend that psychologists were keen to explain was why men commit more crime than women. In an attempt to explain this they took into account genetically normal men (XY chromosomes), and the genetic abnormality XYY. They found that XYY men were more agressive. (They make up 0.001% of the general population, but 1.5% of prisoners). XYY men are also less intelligent, and this is generally used to explain why they turn to crime.

Twins- Monozygotic/identical twins share 100% of their genetic make up. Where as dizygotic twins/fraternal share only 50%. Therefore, any characteristic that is genetically controlled should be the same in MZ twins. Lyons studied juvenile behaviour in twins and found that identical twins were not much more similar that fraternal twins. This suggests that environment plays a massive part in raising a criminal. However, in adulthood MZ twins were much more similar when tested on aggression. This suggests that when DZs have freedom from eachother their behaviour becomes much more different, suggesting a genetic effect.

Adoption studies- Research findings.....Having biological parents with a criminal record increases the chance of sons having a criminal record, suggesting that genes


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