On April 13, 2006, at least five F-2 tornadoes with wind speeds of 150 mph left a path of destruction 4 miles long and 1/3rd of a mile wide in downtown Iowa City the home of the University of Iowa. The storms inflicted serious injuries and extensive damage to several businesses, over 1,000 homes and apartments, and hundreds of automobiles. Many college students and permanent residents were forced to leave their homes because of storm damage. It is estimated that the storms resulted in at least $10 million in damages to public buildings and tens of millions more to private property. This natural disaster provides a unique, time-limited opportunity to examine important questions about perceptions of vulnerability. When people encounter a natural disaster that inflicts extensive injury and damage on their community, what effect does the experience have on their beliefs about vulnerability and preparedness for future disasters? Prior research with populations that have not experienced natural disaster or other kinds of major negative life events indicates that most people tend to believe they are less vulnerable (i.e., unrealistically optimistic) than their peers to future disasters. Less is known, however, about whether this belief changes when a significant negative event actually occurs. The proposed research will determine whether people return to unrealistic optimism and how this relates to future efforts aimed at emergency preparedness. Building on preliminary research with 220 participants contacted within 3-weeks after the tornadoes struck, this project will survey both community residents and college students who reside in Iowa City and were present at the time of the tornados to identify the trajectory of beliefs following a disaster and to advance knowledge about motivational and cognitive processes contributing to unrealistic optimism. Questionnaires/Interviews will be administered at 6- and 10-months post-disaster that contain the same items about beliefs, absolute risk, and objective likelihood. There also will be items about any experience with weather-related disasters or other major negative events since the April tornadoes. ANOVA, t-tests, correlations, and chi-square will be used to examine differences as a function of subject groupings. The tests of changes over time will be assessed with growth curve analysis. ANOVA (or ANCOVA with demographics) will be used to assess differences across cross-sectional samples. Multiple regression will be used to examine the role of potential moderators and mediators of beliefs and preventive behaviors. Because social psychologists conceptualize the illusion of non-vulnerability as one of the fundamental ways that people cope with uncertainty and anxiety about the future, the answers to these questions, in the context of natural disaster, are important and potentially can extend understanding about coping with disasters that affect entire communities. Findings from this research will address theoretical and practical questions about whether the degree of personal exposure and consequences of a disaster influence beliefs of non-vulnerability and emergency preparedness behaviors.