Risky Business: Executive Function, Personality, and Reckless Behavior During Adolescence and Emerging Adulthood Henry Pharo, Clark Sim, Mikala Graham, Julien Gross, and Harlene Hayne University of Otago Adolescence is a risky business. Despite outstanding physical health, the risk of injury or death during adolescence is 2–3 times that of childhood. The primary cause of this increase in morbidity and mortality is heightened risky behavior including drinking, driving, drug-taking, smoking, and unprotected sex. Why is it that some adolescents take big risks, while others do not? One potential source of individual differences in risk-taking behavior may lie in individual differences in executive function including judgment, impulse control, self-monitoring, and planning. Researchers have hypothesized that limited brain system integration and efficiency, particularly in the prefrontal cortex and related structures, may be involved in the range and degree of risky behavior commonly exhibited by teens. In the present study, we examined the relation between risky behavior, personality factors, and performance on neuropsy- chological tests of executive function. The community sample of 136 adolescents aged 13- to 17-years- old and 57 emerging adults aged 18- to 22-years-old exhibited marked individual differences in risk-taking behavior; participants’ scores on a alcohol, smoking, drugs, sex, driving, and antisocial behavior questionnaire ranged from 0 to near the maximum value possible. We found that risky personality and performance on the neuropsychological tests were both significant predictors of real- world risk-taking. These data have important implications for current public policies involving adoles- cents and emerging adults. Keywords: adolescence, risky behavior, executive function, personality The transition between childhood and adulthood is characterized by a remarkable developmental paradox— despite a substantial increase in both physical maturity and cognitive ability, there is also a dramatic increase in morbidity and mortality. Some statistics indicate that mortality rates during adolescence increase by as much as 200% from middle childhood (Dahl, 2004; Spear, 2000). This increase in morbidity and mortality has, in part, been attrib- uted to a sharp rise in risky and antisocial behavior during ado- lescence (Arnett, 1992; Moffitt, 1993). For example, adolescents are more likely than both children and adults to abuse alcohol, use illicit substances, have unprotected sex, commit antisocial acts, drive recklessly, and drive while intoxicated (Steinberg, 2004). But why do adolescents engage in risky behavior? For some researchers, and indeed for many concerned members of the gen- eral public, the hormonal changes that accompany puberty are thought to be responsible for reckless or risky adolescent behavior (Dahl, 2004). Consistent with this view, some researchers have documented an association between the timing of puberty and the emergence of risk-taking and delinquent behaviors. Although early puberty is related to increased risk involvement (Caspi, Lynam, Moffitt, & Silva, 1993; Martin et al., 2002; Williams & Dunlop, 1999), the situation is complicated by the mediating role of expe- rience. For example, Caspi et al. (1993) found that, although girls who entered puberty earlier were more likely to engage in antiso- cial behaviors at age 15 than girls who entered puberty later, this effect was only apparent for those girls who attended mixed-sex schools. Furthermore, the notion that only those who enter puberty early are prone to risk-taking has also been questioned. Williams and Dunlop (1999), for example, found that male adolescents who begin puberty either early or late relative to age-based norms report higher levels of risk-taking and delinquency, especially in the form of school opposition behaviors and crime. These re- searchers propose that those who enter puberty early might engage in higher levels of risk-taking as a result of advanced peer group activities, whereas those who enter puberty late may do so as a means of raising self-esteem and gaining popularity among peers. Researchers have also proposed that pubertal hormones may make a contribution to adolescent emotional volatility (Miller, Buchanan, Eccles, & Becker, 1992) and negative moods (Brooks- Gunn, Graber, & Paikoff, 1994). Although individual differences in levels of androgenic hormones, coupled with individual differ- ences in experience, have been related to variations in the devel- opment of adolescent sexual behavior (Udry, 1988), there is little evidence for a simple connection between pubertal increases in hormones and increases in other forms of risk-taking behavior (Dahl, 2004; Spear, 2000; Spear, 2010). In fact, Dahl (2004) has argued that there is no causal link between hormones and risk- This article was published Online First October 17, 2011. Henry Pharo, Clark Sim, Mikala Graham, Julien Gross, and Harlene Hayne, Department of Psychology, University of Otago, Dunedin, New Zealand. Funding for this research was provided by a Marsden grant from the Royal Society of New Zealand to Harlene Hayne. We thank Marea Co- lombo and Elliot Nicholls for help with participant recruitment, and all of the participants for consenting to take part in the research. Correspondence concerning this article should be addressed to Harlene Hayne, University of Otago, P.O. Box 56, 9054, Dunedin, New Zealand. E-mail: harlene.hayne@otago.ac.nz Behavioral Neuroscience © 2011 American Psychological Association 2011, Vol. 125, No. 6, 970 –978 0735-7044/11/$12.00 DOI: 10.1037/a0025768 970