uncertainty and ambiguity of positive benefits of environmentally-responsible choice options will more likely be seen as a handicap rather than an opportunity. It also suggests a perhaps unexpected advantage of educating the public about technological innovations. Such education not only provides more accurate input for people’s analytic processing of environmentally-relevant choice options, but will also help to remove negative affective reactions to uncertainty that are associated with not well-understood probabilistic mechanisms related to climate events and their consequences.

# **Effect of Small Probabilities**

An important distinction has been recently made between uncertain or risky decisions made from personal experience and those made from statistical description, because the ostensibly-same information about possible outcomes and their likelihood of choice alternatives can lead to different choices depending on how the information was acquired (Hertwig, Barron, Weber, & Erev, 2004, 2006). Decisions from experience know about the range of outcomes of different choice options and their likelihood based on learning (by getting rewarded or by getting hurt), i.e., repeated personal encounters with the uncertain choice options and their realized outcomes, the way animals learn about different foraging environments in their risky foraging decisions (Weber, Shafir, & Blais, 2004). Even though the outcomes of choice options may initially be completely unknown (decisions under ignorance), repeated choices provide the decision maker with feedback about possible outcomes and their likelihood, in the limit with great objective accuracy. Decisions from description, on the other hand, are made based on outcome and probability information provided in some statistical summary that is communicated in verbal, graphic, or numeric form, i.e., learning by being told. This way of information communication and acquisition is available only to humans, with their ability for abstract, symbolic representation, but is the method by which almost all laboratory studies of risky decision making have communicated information about available choice options to respondents (Weber, Shafir, & Blais, 2004).

Knowing how people have come to know about the possible outcomes of real-world choice options and their probabilities matters, because choices differ quite dramatically under the two information conditions when choice options include small probability events. Members of the general public and domain experts often learn about choice option outcomes and their probabilities in different ways. In the case of insurance decisions (e.g., federally subsidized flood insurance (Kunreuther, 1984)), individuals considering the purchase of insurance appear to make their decision based on personal experience with flood events in previous years, whereas the industry experts have access to actuarial information and thus make decisions from description. In the case of childhood inoculation decisions, the situation is the opposite. The pediatrician who administers hundreds of inoculations per year knows about the outcomes and their probabilities of inoculating or failure to inoculate from personal experience, whereas parents make this decision based on a description of outcomes provided in AMA pamphlets or websites. Weber et al.

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