The interface of the social and physical sciences is not unlike that of two fluids of different densities. People firmly self-identify in one category or the other, and rapidly sort themselves accordingly when given the opportunity; and yet, when mixing does occur, interesting phenomena (like gravity waves or hypothetical-hurricane-response research) can occur. I recently heard a talk by Rebecca Morss of NCAR who, in a paper that, due to the magic of Internet pre-publishing, is not coming out until the April edition of its journal, came up with several different warning messages based around the same hurricane scenario and posed them to residents of the South Florida coast. Some were told that 'Hurricane Julia' would cause a storm surge of 4 feet or higher; others, that there was a 55% chance of a direct strike on Miami; a third group, that "evacuation is the most effective way to protect" oneself; a fourth group, that food, water, and communication networks may be severed for weeks; and a final group, that the "storm surge will be extremely violent, destructive, and deadly. [...] You may die." Respondents were also shown a cone of uncertainty of the sort that the National Hurricane Center routinely produces.
The authors found that the preconceptions and heuristics of human information-processing were the single best influence on people's reactions to the hurricane. All else being equal, Hispanics and women were more likely to evacuate, as were older people, those who had evacuated before, and those who had received the "4-ft storm surge" and "extremely violent and dangerous" warnings. Going to rhetorical extremes, while effective in increasing evacuation rates and making the warning memorable, also provoked the biggest backlash; in previous studies, some people have indicated a greater desire to shelter in place because they found the message rude, the source less reliable, or wanted to prove the sender wrong. Whether this increase in urgency of tone would have diminishing returns in future storms as its potency presumably wanes is an open question -- after all, there's only so far you can go towards annihilation before you reach annihilation itself. Relatedly, people with individualist personalities were less likely to evacuate, which the authors attribute to the large body of psychology research supporting the notion that people reject information that doesn't mesh with their worldview, and the government claiming that death and destruction will be visited upon those who disobey certainly clashes with individualism in a strict sense. It's an open question how to tailor these messages to still allow people their independence while encouraging the best decision-making on a society-wide level. Not everyone should evacuate even in a strong storm, for their own specific reasons, but the general consensus among scientists and emergency managers is that more caution would be wise. Whether or not it's, say, economically optimal is another question altogether -- and a very intriguing one at that.
A yawning gap exists between "colloquial" and scientific risk assessment, traceable all the way down to the root of how a risk is described: in common parlance we use words like "dangerous" and "scary", whereas, traditionally, scientists (who write warnings) have described them purely in terms of their quantifiable qualities, for instance a 4-foot storm surge for a duration of 6 hours. As humans, we can't help but be influenced more by the appeal to emotions than to abstractions, perhaps because the abstraction requires an additional cognitive step to reach the conclusion of 'do something!' and our mental alarm bells start ringing. This was succinctly borne out by a study finding that the two biggest factors affecting people's perception of the threat posed by climate change were the elevation and distance from the coast of their own houses. Personal experience trumps vicarious experience and analytic knowledge, especially when life and property is on the line, according to this meticulous and careful review. The book "Thought Contagion" by Aaron Lynch notes more generally that the spread of many ideas can be attributed to either the "cognitive" or "motivational" advantage of adoption in the eyes of the adopter. The former occurs when we believe something to be right intrinsically, the latter when we have an objectively assessed outside motivation for believing it. Turning motivation on its head into risk is a tempting but (as far as I am aware) unproven way to explain these very personal effects on perceptions of global issues. And of course motivation can be derived equally well from conformity or non-conformity, depending on one's personality.
Much more detail on this topic is surely warranted but this post is intended primarily as a meditative musing touching on some of the most interesting questions and findings that interdisciplinary social-physical research has thus far raised. Going beyond the trite 'why do some people not believe climate change is real' study is in my view essential for generating respect for the subfield, and for raising the bar so that a new generation of research questions, taller in stature, can fit underneath.