Abstract
The purpose of this study was to examine and make clear a riky shift phenomenon. In other words, it was attempted to explore the mechanism of diffusion of responsibility that was assumed to exist in a group decision-making situation, operating the extent to which the decision makers felt responsibility toward group members including themselves by varying the number of decision makers within the group.
The task was to bet on simple probability preference. The subjects were 130 first-year students (15 to 16 years old) of a girls commercial high school. The results of this study can be summarized as follows.
1. The larger the number of decision-makers within a group, i. e., the less responsibility they feel toward group members including themselves, the riskier the content of the decision.
2. In cases where there is just one decision-maker within a group, the decision-maker's decision is more cautious than a personal decision prior to the group situation.
The above results suggest that there exists a mechanism of diffusion of responsihility in a group discussion situation and that a risky shift phenomeon is caused by that mechanism.
