Optimism bias about environmental degradation: The role of the range of impact of precautions

Optimism bias regarding environmental degradation may inhibit pro-environmental behaviour. Two studies established that optimism bias regarding environmental events exists and its determinants were investigated. In study 1 (n = 86) optimism bias was observed regarding some aspects of environmental degradation (e.g. air pollution affecting the local area), but not others. These results are consistent with the egocentrism account of optimism bias; egocentric focus on personal precautions may not contribute to optimism bias if others are also perceived to benefit from one's own personal precautions. Study 2 (n = 121) assessed this hypothesis employing a manipulation of the perceived range of impact of risk-relevant behaviours. Subjects judged the likelihood that they and their average peer would be affected by environmental hazards, phrased in either general terms (e.g. air pollution) or specific terms (e.g. respiratory problems due to air pollution). Control subjects made estimates about the specific outcomes not explicitly related to the environment (e.g. respiratory problems). Subjects identified behaviours which influence the likelihood of being affected by each hazard. As predicted, subjects asked about general environmental hazards nominated behaviours likely to benefit many people (e.g. reduced use of ozone-damaging chemicals) and demonstrated less optimism bias than subjects asked about; specific consequences of the same hazards. Optimism bias was negatively correlated with range of impact of precautions. Thus, optimism bias regarding environmental degradation may be limited by a tendency to focus on pro-environmental behaviours with a wide range of impact. (C) 2001 Academic Press.