摘要：Previous research has demonstrated systematic discrepancies between description- and experience-based risky choices. This description-experience gap has been attributed to several factors such as reliance on small samples and differential probability weighting patterns. Because context-dependent outcome expectation regarding safe options might influence experience-based risky choices, it constitutes another potential contributor to the gap. Using a free-sampling paradigm and risky options with rare outcomes that were either attractive or unattractive relative to the frequent ones, two experiments examined the existence and impact of such outcome expectation in experience-based risky choices. Both experiments had two information conditions: hint information meant to eliminate outcome expectation was provided in one condition but not the other. Experiment 1, which indicated the numbers of possible outcomes regarding both safe and risky options under the hint condition, revealed different choice behaviors regarding risky-safe trials between the two information conditions, no matter whether the rare outcome of the risky option in such a trial (i.e., the local context) was attractive or unattractive. However, this result provided only indirect evidence for the role of outcome expectation because it was unclear whether the hint information affected only the outcome expectation and thus evaluation of safe options or the evaluations of both safe and risky ones. With refined hint information arguably removing potential impacts on the evaluation of risky options, Experiment 2 showed that expectation of a non-existent rare outcome of safe options did contribute to experience-based risky choices. In addition, it appeared that the rare outcomes of the risky options in other decision problems presented in the same experiment (i.e., the global context) also affected outcome expectation. Future research could investigate how the interaction between local and global contexts determines outcome expectation to deepen our understanding of its contribution to experience-based risky choice and the description-experience gap.
