decided to provide help. Instead, Ames et al. (2003) found that people’s attitudes towards their helper depended on the mode that they perceived their helpers had used to make the helping decision. Participants in this study reported most favorable evaluations of helpers whom they perceived as having helped “from the heart” and less favorable evaluations of helpers perceived to have been instrumentally concerned with what they would get in return, or who had simply considered role-related obligations.

To the extent that different modes of making a decision lead people to different actions, knowing which version of the “as-if” optimization models was used is of substantial help in predicting choice, accounting for 60 percent of the variance in choices in moral and ethical dilemmas, where perceived costs and benefits of choice options accounted for only 20 percent of the variance in selected options (Krosch, Figner, & Weber, 2011). Predicting behavior and reactions to new institutions or policies based on realistic assumptions about human decision making is, of course, an important role of decision models. It would be foolish not to use the full extent of what we know about when people decide how and why, as it would mean leaving some metaphorical money on the table when it comes to predicting decisions (Weber & Johnson, 2009).

**Extensions from individual decisions to households and other groups**

Research on the social amplification of risk (e.g., Pidgeon, Kasperson, & Slovic, 2003; Hulme, 2009) has examined dynamics and mechanisms beyond individual perception. Sunstein (2006) described differences in what is available to different groups and what gets amplified as a function of their deep-seated values and beliefs. More specifically, people’s worldviews have been shown to shape how they develop attitudes about phenomena like climate change. The sociological theory of moral norm activation (Schwartz, 1977) describes how people decide to act out of a sense of obligation when they become aware of negative consequences to others from some state of affairs and ascribe responsibility for those consequences to themselves. This process affects concern with environmental risks (Dunlap & Van Liere, 1978), including those of climate change (Dietz et al., 2009). Differences in how individuals or groups value consequences to themselves vs. others and about personal responsibility (Schwartz, 1994) affect this process (Stern et al., 1999). A related analysis rooted in anthropology links environmentalism to egalitarian views (Douglas and Wildavsky, 1982; Dake, 1991; O’Connor et al., 1999).

While many of the cognitive and affective processes described above influence both members of the general public and scientists in some contexts, biases in perceptions and reactions tend to be more severe for nonscientists. As a result, scientists and non-scientists differ sharply in their perceptions of climate change. A Pew Research Center (2009) poll found that while 84% of scientists said the earth was getting warmer because of human activity such as burning fossil fuels, just 49% of nonscientists in this U.S. representative sample held this view. Weber and Stern (2011) 25