1. Invulnerability, Optimism Bias and Risk Behavior in Late Adolescence Daniel K. Lapsley and Patrick L. Hill University of Notre Dame, USA Available at: www.nd.edu/~dlapsle1www.nd.edu/~dlapsle1 Background Two explanations of risk behavior are prominent. One explanation suggests that risk appraisal is compromised by a pervasive optimism bias whereby individuals assume more favorable outcomes for the self than for others. This approach follows the biases-and- heuristics paradigm in its assumption that risk judgment is best modeled by asking individuals to estimate the chances, likelihood or probability that negative events would happen to the self (and to others). As intuitive statisticians individuals tend to be optimistic about their chances of getting cancer if they smoke or of contracting an STD if they are sexually active. As Weinstein (1980, p. 806) put it, “people tend to think they are invulnerable.” A second explanation links risk behavior to felt invulnerability that has a presumptive developmental source; or else treats invulnerability not as a cognitive error in decision-making but as an attitudinal variable and as a dimension of individual differences (Lapsley, 2003). To date the invulnerability and optimism bias approaches to risk judgment have not been examined conjointly. Moreover, although optimism bias and invulnerability are said to underwrite “risky decision-making”, few studies have attempted to empirically document this relationship The purpose of this study was two-fold. First, to test the relative contribution of optimism bias and invulnerability to risk behavior. Second, to determine the extent to which invulnerability and optimism bias are associated with risky decision-making. European Adolescent Research Association Turin, May 2008 Conclusions Although invulnerability and optimism bias were moderately correlated, invulnerability was more strongly and pervasively correlated with risk behavior (delinquent behavior and life time drug use) than was optimism bias; and was the sole predictor of risk behavior (and drug use) in regression analysis. In addition, the relationship of invulnerability and optimism bias to risk behavior does not seem to be underwritten by “risky decision- making” as measured by the Iowa Gambling Task. The IGT was not related to these constructs, nor was it correlated with risk behavior. Invulnerability and optimism bias appear to be overlapping but independent constructs that should not be conflated in analysis of risk behavior; nor confused with “risky decision- making” in the sense measured by the Iowa Gambling Task. Method Participants: 114 (78 males) late adolescent (M age = 19.57, SD = 1.29) university students. Instruments: Iowa Gambling Task. The IGT is a measure of “risky decision-making” that requires participants to select among 4 decks of cards that reflect varying degrees of risk. In this study the IGT was scored to reflect the percent of “safe” (non-risky) choices over 100 trials (so that high scores indicate less risky decision-making). Adolescent Invulnerability Scale. The AIS is a 20-item scale that requires participants to indicate their level of agreement with statements that reflect an inability to be injured, harmed or High scores indicate greater felt invulnerability. The reliability was α =.83 Optimism Bias. Participants judged the likelihood of negative outcomes if they engaged in each of 18 behaviors. Risk assessment was both comparative (“Compared to other Notre Dame students) and conditional (“…if you did X”). The rating scale ranged from -3 (Much below average) to +3 (Much above average). Negative scores indicate optimism bias. The reliability was α = 74. Delinquent Risk Behavior. Using a scale designed by Rowe (1985), participants rated the extent to which they engaged in 20 risk behaviors, including fast driving, stealing, fighting, and vandalism, along a 4-step continuum (no/never, one time/rarely, several times, very often). The reliability was α = 83. Lifetime Drug Use Participants indicated how many times in their life they have used alcohol, tobacco and various drugs (marijuana, hallucinogens, cocaine, meth) on scale ranging from “never” to “40 or more” times. The reliability was α = 63. Optimism Bias Ratings (negative scores indicate more optimism bias) ItemsMeanStd. Dev. being injured in a tornado if one struck near you getting caught if you cheat on a test getting an STD if having unprotected sex getting caught for vandalism getting arrested for using illegal substances getting caught illegally downloading materials getting caught for shoplifting becoming an alcoholic if drink regularly having cavities if don’t visit dentist regularly being mugged in a dangerous neighborhood failing a test if don’t study getting an “A” if you study for exam getting an interview if apply for a job being injured if involved in a fight being rejected if ask someone for a date getting divorced if you marry getting in an accident if drive over speed limit getting lung cancer if you smoke regularly -.61 -.52 -.25 -.65 -.71 -.38 -.73 -.67 -.07 -.24.08 -.51 -.87 -.14 -.55 -1.19 -.54.15 1.16 1.27 1.18 1.39 1.68 1.37 1.49 1.38 1.19 1.22 1.47 1.26 1.12 1.29 1.21 1.27 1.07