2.3 The Cambridge Study in Delinquent Development

One method that social scientists use to investigate the causes of antisocial and criminal behaviour is to study a large group of children over a long period of time, and see if any of them commit crimes. Differences between the group can then be explored, for example personality, home life, economic circumstances and so on, to try and determine why some go on to commit crime, as compared to others who do not. This type of research is called a ‘longitudinal study’, as it follows people over a long period to see if their behaviour changes or develops over time.

The Cambridge Study in Delinquent Development was a longitudinal study that began in the 1960s by the criminologist Donald West, although David Farrington, a forensic psychologist, took over the long-term running of the project. The study followed a group of 411 males from the age of 8 years (in 1961), up to the age of 48 years. All the boys were from working-class backgrounds and living in a deprived area of south London. The aim was to investigate the development of delinquent and criminal behaviour in inner-city males, and whether it was persistent over time. The study was not designed to test any one theory of delinquency, but to try and investigate:

• why delinquency began
• whether it could be predicted in advance
• if it continued into adult life.

The boys who took part in the study were interviewed and tested nine times throughout the study. The tests measured individual characteristics, such as personality and intelligence. The interviews investigated issues such as living circumstances, employment, relationships, leisure activities and offending behaviour. When the boys were at school, their teachers also filled out questionnaires about their behaviour and school attainment; and their peers were asked about issues such as popularity, risk-taking behaviour and honesty.

When the males reached 32 years of age, criminal record checks were conducted to determine how many had commited criminal offences and what type of offences they were. The study found a number of predictors at 8–10 years of age, which were thought to be related to later delinquency and offending. These fell into six categories (Farrington, 1995; Farrington et al., 2006):

1. Antisocial behaviour, including being troublesome in school, dishonesty and aggressiveness.
2. Hyperactivity, attention deficit disorder, daring, risk-taking and poor concentration.
3. Low intelligence and poor school attainment.
4. Family criminality, convicted parents, older siblings and siblings with behavioural problems.
5. Family poverty, large family size and poor housing.
6. Poor parental child-rearing behaviour, including harsh and inconsistent discipline, poor supervision, neglect and parental conflict.

The study also found that when the men were aged 32, just over a third (37 per cent) had been convicted of a criminal offence. This rose to only 41 per cent when the men were surveyed at 48 years. The most frequent number of offences were committed when the men were aged 17−20 years of age, suggesting that if males were at risk of becoming criminals, then this was the age at which they were most likely to offend. Farrington et al. (1986) found that the men in the study were more likely to commit offences while they were unemployed, as compared to being employed. When the types of offences were examined, it was found that the increase in offences when unemployed centred on offences that involved material gain, such as theft, robbery and fraud, and not offences that involved violence. This suggests that a shortage of money during unemployment may have been an increasing risk factor that led to crime.

The findings from the Cambridge study show that personality is an important factor in whether someone commits crime, for example those who are impulsive and like to take risks are more likely to commit crime. However, the findings from the study also showed that there were other factors in addition to personality that may influence young people to act in antisocial ways or commit criminal acts. The additional risk factors thought to be associated with future criminal behaviour included a family history of offending, child-rearing practices and family poverty. However, which risk factors were considered to be the most important or how they interacted with each other were not discussed in the findings from this study.