Jacob's XYY Study

• 'Super Male Syndrome' is a male inheriting an extra Y chromosome which leads to them developing such characteristics; tall, well - built, low intelligence, more aggression and violence ( this can lead to them committing violent crimes such as murder).
• The general population having XYY - 1 in 1000 men

  Men in prison having XYY - 15 in 1000 men (suggests genes can influence crime).
• Price & Whatmoore (1967) - studied imprisoned criminals in secure psychiatric hospitals where a higher percentage of inmates had XYY syndrome. These males were unstable, tending to commit motiveless property crimes.
• SUPPORTED - There is a clear association found out by Jacob et al between XYY syndrome and violent offenders. Supporting evidence by Price & Whatmoore.
• INFLUENCED - Helped to highlight why some males may be more aggressive and likely to commit crime. This helps our understanding.
• IGNORES - Too simplistic - fails to recognise other important factors as to why people turn to crime. Even if violent offenders have XYY syndrome, there is no proof it is the cause of their behaviour.
• Jacobs also failed to consider that many of these individuals would have grown up with difficult childhood experiences or suffered from mental health problems which could explain their actions rather than genetics.
• They did not take into account any environmental influences on criminality such as poverty, poor education, lack of employment opportunities etc.
• The sample size was very small so we cannot generalize findings to all men with this chromosome combination
• NOT ALL PEOPLE - Ignores women and the reasons why they commit crimes. This is known as androcentrism (focuses solely on men). Women can have an extra chromosome - XXX- which also affects their behaviour.
• NOT ALL CRIMES - Cannot explain much of the crime that happens since it is only explaining violent crimes - it doesn't explain intelligent crimes such as white collar and technological.
• ETHICAL CONCERNS - If someone has been diagnosed with a particular gene linked to violence, then they may feel stigmatized and treated differently because of it.
• ETHICAL CONCERNS - There are concerns about how genetic information will be used by governments and insurance companies to make decisions about people based on their genes.
• ETHICAL CONCERNS - Some argue that it is unethical to use genetic testing to determine whether someone will become a criminal. They believe that everyone deserves a fair trial based on evidence, not just their DNA.
• ETHICAL CONCERNS - There are ethical concerns about using genetic information to predict future behavior. It may be used by employers or insurance companies to discriminate against those who carry certain genes.