Proceedings of the Annual Meeting of the Cognitive Science Society

Previous studies have shown that people’s decisions are af-fected by context in various ways, even when they are providedwith the same or analogous information. In the present study,we analyzed decisions based on verbally expressed probabilis-tic phrases (verbal probabilities) and examined how contextualfactors affected such decisions. In particular, we focused on thedifference in contexts that produced different probabilistic be-liefs with regards to uncertain events. We hypothesized thatsuch contextual effects could be explained in terms of a Deci-sion by Sampling (DbS) account (Stewart et al., 2006). In orderto examine our hypothesis, we proposed a modified version ofDbS, Decision by Belief Sampling (DbBS), and conducted be-havioral experiment about decision making. In this experiment,we set different contexts that we expected to produce differentprobabilistic beliefs regarding uncertain events for decision-makers and examined how such differences affected decisionmaking. Results showed that decisions were significantly af-fected by the variation in contexts, and DbBS well explainedsuch effects.