Peer Influence on Risk Taking, Risk Preference, and Risky Decision Making in Adolescence and Adulthood: An Experimental Study Margo Gardner and Laurence Steinberg Temple University In this study, 306 individuals in 3 age groups—adolescents (13–16), youths (18 –22), and adults (24 and older)— completed 2 questionnaire measures assessing risk preference and risky decision making, and 1 behavioral task measuring risk taking. Participants in each age group were randomly assigned to complete the measures either alone or with 2 same-aged peers. Analyses indicated that (a) risk taking and risky decision making decreased with age; (b) participants took more risks, focused more on the benefits than the costs of risky behavior, and made riskier decisions when in peer groups than alone; and (c) peer effects on risk taking and risky decision making were stronger among adolescents and youths than adults. These findings support the idea that adolescents are more inclined toward risky behavior and risky decision making than are adults and that peer influence plays an important role in explaining risky behavior during adolescence. Keywords: adolescents, risk taking, peer influence, risk preference, decision making It is well documented that adolescents are more likely than adults to engage in risky behavior. For example, adolescents are more likely than adults to drive recklessly, to drive while intoxi- cated, to use varied illicit substances, to have unprotected sex, and to engage in both minor and more serious antisocial behavior (Arnett, 1992). However, despite clinical and anecdotal evidence of heightened real-world risk taking during adolescence, labora- tory studies of age differences in risk preference, risk perception, and risky decision making have not yielded consistent evidence that adolescents are actually less risk averse than are their elders. In fact, it is often asserted that, by midadolescence, teens’ capac- ities for understanding and reasoning in risky decision-making situations roughly approximate those of adults (Fischhoff, 1992; Furby & Beyth-Marom, 1992). This assertion has been used to argue both for protecting adolescents’ rights to make autonomous decisions about their reproductive health and for holding adoles- cents to adult standards of criminal blameworthiness (see Stein- berg & Scott, 2003, for a discussion). However, as several writers have recently argued, extant studies suggesting equivalent orientations toward risk among adolescents and adults are only modestly useful in understanding how adoles- cents compare with adults in real-world decision making. These authors suggest that typical laboratory studies of risky decision making fail to consider the emotional and social contexts in which risk taking actually occurs (Cauffman & Steinberg, 2000; Scott, Reppucci, & Woolard, 1995; Steinberg, 2004; Steinberg & Cauff- man, 1996). In such studies, individual adolescents are presented with hypothetical dilemmas under conditions of low emotional arousal and are then asked to make and explain their decisions. In the real world, however, adolescents’ decisions are not hypothet- ical, they are generally made under conditions of emotional arousal (whether negative or positive), and they are usually made in peer groups. Whether the risky decision making of adolescents is truly comparable to that of adults under real-world conditions remains an open and unstudied question. A number of explanations have been advanced to account for differences between adolescents and adults in real-world, as op- posed to laboratory-based, risk taking. Some have argued that age differences in psychosocial capacities such as impulse control or sensation seeking play an important role (see Steinberg & Cauff- man, 1996). Consistent with this, Cauffman and Steinberg (2000) reported that once differences in psychosocial maturity between adolescents and adults are accounted for, age differences in risky decision making disappear. An alternative and entirely compatible account of age differences in risky behavior emphasizes the role of peers and, more specifically, peer influence. That is, adolescents may engage in more risky behavior than do adults because they are more susceptible to the influence of their similarly risk-prone peers. Support for this latter explanation comes, in part, from the criminology literature. There is a small but compelling body of evidence to suggest that when adolescents commit crimes—acts that are inherently risky—they generally do so with their peers (Erickson & Jensen, 1977; Zimring, 1998). For example, adoles- cents are usually accompanied by one or more persons when committing crimes that range in seriousness from vandalism and drug use (Erickson & Jensen, 1977) to rape and homicide (Zim- Margo Gardner and Laurence Steinberg, Department of Psychology, Temple University. This study was supported by a grant from the John D. and Catherine T. MacArthur Foundation Network on Adolescent Development and Juvenile Justice. We thank Rebecca Davis, Rebecca Garrett, Lauren Guttshall, Nermine Salama, Benjamin Steinberg, and Erica Weitz for help with data collection. We also thank He Len Chung, Alex Piquero, and Jennifer Silk for their help with the selection and implementation of the analytic method used. Correspondence concerning this article should be addressed to Margo Gardner at the Department of Psychology, Temple University, Philadel- phia, PA 19122. E-mail: mnoel002@temple.edu Developmental Psychology Copyright 2005 by the American Psychological Association 2005, Vol. 41, No. 4, 625– 635 0012-1649/05/$12.00 DOI: 10.1037/0012-1649.41.4.625 625