健康食品の効能とリスク判断に及ぼすサンプルサイズ情報の影響

抄録

This study examined whether people take sample size information into consideration when judging the dietary effect and the side-effect risk of dietary food. Undergraduate students (N = 152) were required to read one of three passages, each with different sample size scenarios (2, 40, and 1000), describing the dietary effect and the side-effect risk of dietary food. After that, they were asked to judge the probability of the dietary effect and side-effect of the food to occur and to give the reason for that judgment. As a result, while sample size information did not influence dietary effect judgments, the increase in sample size from two to 40 significantly increased side-effect risk perception. In contrast, the increase in sample size from two to 1000 did not significantly increase risk perception. Detailed analysis of the reasons given to the judgments suggests that participants were not sensitive to large sample size information.