Amish youth enter a decision-making period, beginning on their 16th birthday and lasting potentially several years, within which they are to contemplate whether they will retain or repudiate Amish identity. During this "simmie" period, Amish youth must respond to implicit cultural prescriptions for deviance that have been constructed by adult Amish culture. Because most Amish parents do not openly object to this deviance, the deviance is implicitly sanctioned. Data for the current study were collected as part of a larger ethnographic study, and it involved more than 60 in-depth interviews with Amish who ranged in age from 16 through 76, although most participants were approximately age 16 to 40. The sex ratio was equal. Assessment of the affective response to deviance was based solely on participants' qualitative self-reports and descriptions of their experiences. The findings were used to test selected propositions of Terror Management Theory (TMT) (Pyszczynski, Greenberg, and Solomon, 1997), which provides a theoretical framework through which to examine social competence and agency during youth development. One of the primary tenets of TMT is that youth culture develops as a "cultural-anxiety buffer" against the reality of mortality. This study found evidence to support the basic principles of TMT, albeit in an unexpected and indirect fashion. Rather than function as a specialized cultural-anxiety buffer against fear generated by the contemplation of mortality, as TMT would predict, the deviance prescribed for youth culture produced high levels of anxiety and depression for Amish youth. In this cultural context, youth found existential value in adult, not youth, culture. "Simmies" apparently do not feel compelled to end their period of great uncertainty and vulnerability by quickly adopting or repudiating Amish identity. They understand the significance of the decision they are being asked to make, and they engage in careful and prolonged introspection and deliberation, thus demonstrating high levels of social competence and agency. 25 references