In the Netherlands, with a population of roughly 16 million people, around 1.2 million offences are registered by the police every year. Many of those crimes are committed by young people. In 2009, over 25 per cent of all suspects arrested were aged between 16 and 22. This is over 2.5 times as many as would be expected if age and (suspicion of a) crime were unrelated (Eggen and Kessels, 2010). Unsurprisingly, adolescent delinquency is high on the agenda of criminologists and policy makers alike.
Figure 13.1 depicts the age distribution of crime in 2009 based on Dutch police data. The graph shows a steep rise from age 12 onwards to a peak during the late teenage years when offending is most common. After that, the number of offenders gradually declines during the adult years to almost zero at old age. In criminology, this skewed bell-shaped association between age and crime is referred to as the age-crime curve, which has been replicated across many countries and historical periods. Explanations offered for the age-crime curve have differed radically, as have the remedies to combat delinquency and crime emanating from them.
Against the background of this age-crime debate, this chapter focuses on one of the currently most influential explanations of the association between age and crime: the Dual Taxonomy (Moffitt, 1993). This theoretical framework proposes a complementary set of developmental theories explaining patterns of both Life course persistent and Adolescence-limited offending which it is suggested underlie the age-crime curve. The chapter describes the effects of social cognition and social influence on criminal behaviour that figure prominently in this taxonomy, the way the core premises of the taxonomy have been tested, and prevention and intervention efforts that can be derived from this taxonomy.
Explaining the age-crime curve
Criminologists define the criminal career as the longitudinal sequence of crimes committed by an individual offender (Blumstein et al., 1986). Several criminal career dimensions can be distinguished, including (age of) onset or first-time participation in offending, the frequency of offending, and the duration of the offending period, defined as the interval between the first and last offence.