Understanding and valuing environmental issues: The effects of availability and anchoring on judgment

This paper addresses the effects of availability and anchoring-and-adjustme nt on people's beliefs and values concerning environmental issues. The firs t three studies focus on lay people's perceptions of the causes of large sc ale environmental risks, the second series of three studies deals with how people value environmental goods and how much they are prepared to pay to m itigate environmental risks. In studies 1-3 we investigate the effects of a vailability and anchoring-and-adjustment on estimating the contribution of various factors to large scale environmental risks. Highly complex risks su ch as acid rain and global warming tend to be associated with multiple caus es, and our results show that estimating the role of these causes is clearl y affected by availability and anchoring-and-adjustment. Both have sizeable effects and persist over time. Moreover, corrective procedures only seem t o have a limited effect. Availability and anchoring-and-adjustment not only play a role in judging the possible causes of risks; they also play a role in research attempting to assess the public's willingness to pay (WTP) to protect our environment. The outcomes of WTP surveys are often used as a to ol to help policy decision making. In the second part of this article we pr esent three studies on this issue. Results provide further evidence of the impact of the two heuristics on the outcomes of WTP research. Implications for research and practice are briefly discussed.