Group Size Effects on Risk Perception: A Test of Several Hypotheses

Yamaguchi (1998) found that people perceived a lower level of risk in a group than when they were alone, despite the fact that being in a group did not reduce the objective level of risk. Three experiments were conducted to examine several potential explanations for this effect. Experiment 1 replicated the group size effect in self-perception as well as the perception of the risk level of others. Results did not support the interdependence hypothesis and the affiliation hypothesis. Experiments 2 and 3 tested a hypothesis based on the availability heuristic. The group size effect was reduced or nullified when the target of risk judgment was associated with risk-seeking behavior or when an accident, in which many people died, was made salient.