Informational Cascades, Reputational Cascades, Group Polarization, and the Climate Emails

Cite this Article
Thomas A. Lambert, Informational Cascades, Reputational Cascades, Group Polarization, and the Climate Emails, Truth on the Market (December 10, 2009),

It’s been interesting to observe the responses to the hacked emails from the Climate Research Unit at the University of East Anglia. The emails seem to show leading global warming scientists massaging data to generate the result they prefer (i.e., “I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years … to hide the decline”), scheming to squelch opposing evidence (i.e., “I can’t see either of these papers being in the next I.P.C.C. report. Kevin and I will keep them out somehow—even if we have to redefine what the peer-review literature is!”), admitting to a need to hide certain data from critics (“If they ever hear there is a Freedom of Information Act now in the UK, I think I’ll delete the file rather than send to anyone”), and even confessing that they were “tempted to beat” up researchers with opposing viewpoints.

The mainstream press and climate policymakers have largely brushed off these emails and have treated anthropogenic global warming as a settled scientific fact. For example, in reporting the story of the climate emails, the New York Times stated that “[t]he evidence pointing to a growing human contribution to global warming is so widely accepted that the hacked material is unlikely to erode the overall argument.” At the White House, Climate Czar Carol Browner dismissed the emails as an irrelevant distraction. And in announcing the EPA’s recent conclusion that carbon dioxide endangers public health and welfare (and is thus subject to extensive regulation under existing environmental statutes), EPA Administrator Lisa Jackson deflected questions about the emails by curtly noting that “[t]he science has been thoroughly evaluated.”

What could explain this apparent lack of concern about these emails, which strongly suggest that the scientific evidence has been doctored? An obvious possibility is that the powers that be realize we’re on the verge of implementing policies they’ve long favored — significant carbon caps, either via legislation or EPA rulemaking — and they don’t want to do or say anything that might prevent that outcome.

But we might be able to explain the absence of alarm on less cynical grounds. As Cass Sunstein has observed, when people have to make complicated risk judgments under uncertainty, they frequently fall prey to psychological and social forces that make them wary of questioning the conventional wisdom about particular risks. In his 2002 book, Risk and Reason, Sunstein explained how informational cascades, reputational cascades, and group polarization can collectively cement — and even strengthen — ill-founded risk judgments:

An informational cascade occurs when people with little personal information about a particular matter base their own beliefs on the apparent beliefs of others. Imagine, for example, that Alan says that abandoned hazardous waste sites are dangerous, or that Alan initiates protest activity because such a site is located nearby. Betty, otherwise skeptical or in equipoise, may go along with Alan; Carl, otherwise an agnostic, may be convinced that if Alan and Betty share the relevant belief, the belief must be true. It will take a confident Deborah to resist the shared judgments of Alan, Betty, and Carl. The result of th[is] set of influences can be social cascades, as hundreds, thousands, or millions of people come to accept a certain belief simply because of what they think other people believe. …

In the case of a reputational cascade, people do not subject themselves to social influences because they think that others are more knowledgeable. Their motivation is simply to earn social approval and avoid disapproval. … If many people are alarmed about some risk, you might not voice your doubts about whether the alarm is merited, simply in order not to seem obtuse, cruel, or indifferent. … Sometimes people take to speaking and acting as if they share, or at least do not reject, what they view as the dominant belief. As in the informational context, the outcome may be the cleansing of public discourse of unusual perceptions, arguments, and actions. … Lawmakers, even more than ordinary citizens, are vulnerable to reputational pressures; that is part of their job. They may even support legislation to control risks that they know to be quite low. …

When like-minded people are talking mostly to one another, especially interesting things are likely to happen. If members of a group tend to think that global warming poses a signficant danger, their discussions will move them, not to the middle, but to a more extreme point in line with their original tendencies. … If members of a group tend to believe that for cancer, the serious dietary problem lies in the use of pesticides, those same people will tend, after discussion, to have a heightened fear of pesticide use. All these are examples of group polarization — a process by which people engaged in process of deliberation end up thinking a more extreme version of what they already thought. Group polarization is central to the cascade-like processes discussed here. If like-minded people are speaking mostly with one another, they can end up with intensely heightened concerns about small risks.

Now I’m not arguing that the risks associated with anthropogenic global warming are small. On that matter, I’m agnostic. I do think it’s appropriate, though, to ask whether our climate policymakers and the members of our media elite are beset by the same social forces that influence the masses. Their lack of concern about the climate emails suggests that they may be. Consider, for example, Climate Czar Browner’s response to questions about the emails:

There has been for a very long time a very small group of people who continue to say this isn’t a real problem, that we don’t need to do anything. On the other hand, we have 2,500 of the word’s foremost scientists who are in absolute agreement that this is a real problem and that we need to do something and we need to do something as soon as possible. What am I going to do, side with the couple of naysayers out there or the 2,500 scientists? I’m sticking with the 2,500 scientists.

Of course, many of the 2,500 scientists “who are in absolute agreement” are Betties, Carls, Deborahs, Edwards, etc. who have formed their beliefs, at least in part, on the basis of evidence presented by a tainted Alan. And the Carol Browners and Lisa Jacksons of the world are certainly worried about preserving their reputations (not to mention, their jobs)! And they and their fellow policymakers have left their nests of like-minded folks in Washington, Geneva, etc. and convened to form an even larger community of like-minded folks in Copenhagen. Informational cascades, reputational cascades, and group polarization — oh my!