Distinguishing between Early and Late Onset Delinquents: Race, Income, Verbal Intelligence and Impulsivity

Abstract

In 1993, Terrie Moffitt proposed a dual taxonomy of adolescent delinquent behavior. She proposed that life course persistent antisocial behavior was characterized by neurological deficits in executive functions, which then result in behavioral impulsivity, and deficits in verbal intelligence. She proposed that these deficits would interact with negative environments (such as low socioeconomic status or ineffective parenting) to produce an early (preadolescent) onset of antisocial or delinquent behavior that would persist through adolescence and well into adulthood. In contrast, she described adolescence-limited delinquent behavior as being engaged in by adolescents in response to peer models, and that this type of antisocial behavior would be characterized by exposure to delinquent peers and cultural and historical context, rather than by neurological deficits involving impulsivity and low verbal intelligence. There have been several attempts to test Moffitt's predictions about the relationship between impulsivity and early onset antisocial behavior. White, Moffitt, Caspi, Bartusch, Needles, and Stouthamer-Loeber (1994) categorize the two approaches to measuring impulsivity as cognitive (using neuropsychological tests) and behavioral (using various observer or self reports of impulsive behavior). They found that behavioral impulsivity is more strongly related to delinquent behavior for males at ages 10 to 13 than is cognitive impulsivity. They did not specifically test Moffitt's hypothesis by examining the impulsivity of late onset delinquents. Taylor, Iacono, and McGue (2000) found both cognitive and behavioral impulsivity was greater in delinquents with an onset earlier than 11 years old than in late onset delinquents (onset 12 or later) or nondelinquent controls. Silverthorn, Frick, and Reynolds (2001) measured impulsivity using the Antisocial Process Screening Device (Frick & Hare, 2001) and found that adolescent males with an early onset of antisocial behavior showed significantly poorer impulse control than males with a later onset of delinquency. White, Bates and Buyske (2001) found that adolescent males, whose antisocial behavior persisted into adulthood, showed more behavioral impulsivity than did those whose delinquency ended after adolescence. Raine, Moffitt, Caspi, Loeber, Stouthamer-Loeber, and Lynam (2005) used cognitive measures of executive functioning/impulsivity and found no difference in the functioning of adolescents with adolescence-limited antisocial behavior and those with life course persistent antisocial behavior. However, Raine et al. (2005) did find that adolescents with life course persistent antisocial behavior had higher rates of diagnosis with attention deficit/hyperactivity disorder than did adolescents with adolescence limited antisocial behavior. There have been few direct tests of Moffit's (1993) hypothesis regarding lower verbal intelligence in early onset delinquents. Taylor, Iacono, and McGue (2000) reported lower verbal intelligence in a sample of early onset delinquents, when compared to the later onset delinquency group and a non-delinquent control group. This study included 36 early onset delinquents, 86 late onset delinquents, and 25 nondelinquent controls. Silverthorn, et al. (2001) compared the intelligence of males with early onset delinquent behavior to males with late onset delinquent behavior and found no significant difference. However, the sample sizes were so small (11 early onset and 12 late onset) that statistical power was extremely limited. White, et al. (2001) compared the verbal abilities of adolescence-limited delinquents with the verbal abilities of adolescents whose antisocial behavior persisted through adulthood and found no significant difference. The trend, though non-significant, was for adolescence-limited delinquents to have higher verbal ability than the persistent delinquents. This study included 230 adolescence-limited delinquents and 49 delinquents whose criminal behavior persisted into adulthood. …