Abstract Empirical studies have indicated a relationship between self-complexity and stress, such that greater self-complexity is associated with reduced stress. In addition, previous research has suggested that greater self-complexity allows for more advantageous decisions. Finally, previous studies have demonstrated a bidirectional relationship between adaptive decision-making and stress, such that increased stress is associated with a decreased ability to make adaptive decisions, which, in turn, increases future stress. However, no research to date has examined the mechanism behind these relationships. We hypothesized that greater self-complexity would lead to less stress and this relationship would be mediated by increased adaptive decision-making. Fifty-six college students at a private Midwestern university took part in the study. We manipulated self-complexity by asking participants to assign traits to their future self according to three (low complexity) or seven (high complexity) different self-aspects, consistent with a previous manipulation of self-complexity by Setterlund (1994). Next, participants underwent a task—used previously by Levin et al. (2007)—to measure their adaptive decision-making in which they selected either one cup for a guaranteed amount of money, or a set of cups, which would statistically yield a greater or lesser sum of money. Finally, participants took a college student stress scale. The main hypothesis was not supported, as the present study did not find that adaptive decision-making mediated the relationship between self-complexity and stress. However, self-complexity did significantly predict adaptive decision-making for the “risky loss” trials. No other paths yielded significant relationships
