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Psychology unit 3 aggression
Genetic factors into aggressive behaviour- XYY chromosome
Some people have an extra Y chromosome. As males are more aggressive than
females this extra Y chromosome is thought to cause additional aggressive
Jacobs found that 3% of inmates had the XYY chromosome compared to 0.1% of
the wider population. This suggests that XYY might be linked to criminality. This
could also be due to lack of intelligence meaning these criminals are the ones who
are most likely to be caught. Additionally it has been found that XYY's tend to
have higher testosterone levels and lack intelligence.
Witken found that whilst XYY's were more likely to commit crimes, their crimes
didn't appear to be aggressive in nature. This means that XYY is more likely to be
linked to criminality and not to aggression.