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Cultural Cognition of Scientific Consensus

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Cultural Cognition and Public Policy

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SCS vs. AOT ... latest "politically motivated reasoning steel cage match" 

So here’s a bit more on the new paper that I mentioned yesterday.

In it, Jonathan Corbin & I analyze how Actively Open-minded Thinking (AOT) relates to acceptance of (“belief in”) human-caused climate change.  AOT reflects the disposition to  seek out, engage, and give appropriate weight to evidence that challenges one’s existing beliefs (Baron 2008; Stanovich and West, 1997).

But we found that higher levels of AOT, as measured by a standard scale (Baron et al. 2015; Harat et al. 2013), magnify political polarization over the reality of human-caused climate change. 

This is surprising because AOT consists in a tendency to resist confirmation bias of the sort that would predictably reinforce partisan divisions on contested issues. So one might well have expected AOT to result in some degree of convergence, not enhanced divergence, in the beliefs of those partisans who score highest on a standard AOT measure.

As I’ve noted in some posts relating to a recent paper in the Annenbenberg Public Policy Center/Cultural Cogniton Project Science of Science Communication Initiative series (Kahan, Landrum, Carpenter, Helft & Jamieson in press), science curiosity does seem to generate that sort of convergence.  As rare glimpse of precise moment of conception of academic paper . . . click it!partisans’ science curiosity, measured by the APPC/CCP Science Curiosity Scale (SCS) increase, their acceptance of human-caused climate change uniformly increases.

Indeed, the magnification of polarization perversely associated with greater science comprehension generally is negated in individuals who score high in SCS.

Jonathan and I wanted to figure out if this was a feature SCS shared with AOT.

But in fact, the greater magnification of polarization that these reasoning dispositions manifest—a dynamic I’ve referred (or attributed) to “motivated system 2 reasoning”—seems to affect AOT, too.

So in this regard, AOT, like numeracy, CRT, and Ordinary Science Intelligence is recruited as a foot soldier in the imperial campaign of our identity-protective selves to rule over the empire of our cogntive life . . . .

Our that’s one interpretatioin. Maybe something else is going on!

But in any case, SCS alone seems to resist this tendency.

So in this sense, the paper is an outgrowth of the latest string of motivated-reasoning “seel-cage matches,” in which SCS has gone toe-to-toe, neuron-to-neuron against an all-star cast of reasoning-disposition measures and bested all of them in the search for an individual difference that counteracts the tendency of people to form and persist and beliefs that cohere with their identity-defining group affiliations.

In this ase, AOT and SCS were not in the same data set, so it was sort of a virtual cage-match. So critical, reflectiveve readers should take that into account as well in taking stock of the results.

SCS continues on its undefeated rampage in brutal cognitive steel-cage matches ... I hope everyone is wearking protective headgear! Click click click!That that into account along with all the other considerations that bear on the weight to be assigned on bit of evidence relevant to an issue or set of issues no one study or even set of studies should ever be taken to “definitively resolve.”

The advancement of knowledge consists in the permanent assimilation of all that is known without all that we may yet come to know in our assessment the relative plausibility of competing conjectures.

Now there is at least one other thing to say about my and Jon’s new paper: it’s inconsistency with the so-called “asymmetry thesis,” which posits that the incidences of politically motivated reasoning are a feature uniquely or at least predominantly associated with ideological conservatism as a personality trait (e.g., Jost et al. 2003).

More on that “tomorrow. . . .”


Baron J (2008) Thinking and deciding. New York: Cambridge University Press.

Baron J, Scott S, Fincher K, and Metz, SE (2015) Why does the cognitive reflection test (sometimes) predict utilitarian moral judgment (and other things)? Journal of Applied Research in Memory and Cognition 4: 265-284.

Haran U, Ritov I, and Mellers BA (2013) The role of actively open-minded thinking in information acquisition, accuracy, and calibration. Judgment and Decision Making 8: 188.

Jost JT, Glaser J, Kruglanski AW, and Sulloway FJ (2003) Political conservatism as motivated social cognition. Psych. Bull. 129: 339-375.

Kahan, D.M., Landrum A.R., Carpenter, K., Helft., L., & Jamieson, K.H. Science curiosity and political information processing (in press). Advances in Political Psychology),

Stanovich KE, West RF (1997) Reasoning independently of prior belief and individual differences in actively open-minded thinking. Journal of Educational Psychology 2: 342-357.


Does "Actively Open Minded Thinking" Aggravate Political Polarization on Climate Change? Looks like it . . . (New paper)

I’ll likely have more to say about this little (it really is little—< 2,000 words) paper.  But for now suffice it to say that I’ve fallen off the wagon and am back to the asymmetry thesis . . . . It will never let me go!


SCS vs. CRT: Another politically motivated reasoning steel cage match!

I’ve been getting a lot of questions about how the   Annberg Public Policy Center/Cultural Cogntion Project “Science Curiosity Scale” (SCS) relates to other measures of open-mindedness.

The Cognitive Reflection Test (Frederick 2005), which assesses the disposition of individuals to consciously and deliberately interrogate their intuitions, is often viewed as such a measure (e.g., Campitelli & Labollita 2010; Pennycook, Cheyne et al. 2013).

One would expect there to be a modest correlation between a measure of open-mindedness and science curiosity, and there is one between CRT and SCS:

But the correlation is only modest: the probability that someone in the top general population decile of CRT—someone who scores a perfect 3—is only 2x as likely as someone who scores zero on CRT to be in the top general population decile of SCS. 

Obviously, the two aren’t measuring the same thing.

This is a picture of the "raw" data for the figure below. Always always consume raw data before exposing yourself to a multivariate analysis--or you could end up bamboozled!They also don’t predict the same style of political information processing.

Despite arguably being the best measure of reflective thinking (Toplak, West & Stanovich 2013), CRT magnifies politically motivated reasoning (Kahan 2013).

That’s why polarization on an issue like human-caused climate change increases as CRT scores go up. As their SCS scores go up, in contrast, individuals don’t become more polarized but rather become more accepting, regardless of their political outlooks.

Here's the regression model for the last figure. If someone shows you only this when reporting his or her data, demand your money back!Indeed, the polarizing influence of science comprehension is suppressed by higher science curiosity as measured by SCS.

As I explained “yesterday,” this is plausibly attributed to the willingness of individuals who are high in science curiosity to expose themselves information that contravenes their political predispositions, something that partisans ordinarily are loath to do and that is not predicted by other dispositions, including CRT, associated with greater science comprehension.

This is one of the findings in the APPC/CCP paper “Science Curiosity and Political Information Processing,” which is forthcoming in Advances in Political Psychology.

There’s no question that the CRT measures an important species of critical reasoning.  I’d experience a degree of shock that even the subjects in the Milgram experiment would have balked at imposing were it to turn out that SCS came within a mile of CRT in predicting resistance to heuristic information processing generally.

But when it comes to predicting resistance to politically biased information processing, SCS picks up on an individual difference in cognition that evades CRT.


Campitelli, G. & Labollita, M. Correlations of cognitive reflection with judgments and choices. Judgment and Decision Making 5, 182-191 (2010).

Frederick, S. Cognitive Reflection and Decision Making. Journal of Economic Perspectives 19, 25-42 (2005).

Kahan, D.M. Ideology, Motivated Reasoning, and Cognitive Reflection. Judgment and Decision Making 8, 407-424 (2013).

Kahan, D.M., Landrum, A.R., Carpenter, K., Helft, L. & Jamieson, K.H. Science Curiosity and Political Information Processing. Advances in Political Psychology  (in press).

Pennycook, G., Cheyne, J.A., Barr, N., Koehler, D.J. & Fugelsang, J.A. Cognitive style and religiosity: The role of conflict detection. Memory & Cognition 42, 1-10 (2013).

Toplak, M.E., West, R.F. & Stanovich, K.E. Assessing miserly information processing: An expansion of the Cognitive Reflection Test. Thinking & Reasoning 20, 147-168 (2014).




Cultural cognition of weather: a cool (or warm) guest post!

And now for something completely different-- a guest post from someone who knows what he's talking about! (And is this just my politics speaking or was July really friggin hot?!)

Cultural Cognition of Weather
by Larry Hamilton
Carsey School of Public Policy, Univ. New Hampshire

December of 2015 was the warmest ever recorded in New Hampshire, by far. Indeed, in temperature anomaly terms (degrees above or below average) it was the warmest of any month for at least 121 years. January, February and March of 2016 were less extreme but each still ranked among the top 15, making winter 2015–2016 overall the state’s warmest on record — eclipsing previous records set successively in 1998, 2002 and 2012 (Figure 1).

Seeing in this record a research opportunity, colleagues and I added a question to a statewide telephone survey conducted in February 2016, to ask whether respondents thought that temperatures in the recent December had been warmer, cooler, or about average for the state. Two months later (April), we asked a similar question about the past winter as a whole. Physical signs of the warm winter had been unmistakable, including mostly bare ground, little shoveling or plowing needed, poor skiing, spring-like temperatures on Christmas day, and early blooming in a state where winters often are snowy and springs late. Not surprisingly, a majority of respondents correctly recalled the warm season. Their accuracy displayed mild but statistically significant political differences, however. Tea Party supporters, and people who do not think that humans are changing the climate, less often recalled recent warmth (Hamilton & Lemcke-Stampone 2016). Although percentage differences were not large, these patterns echoed greater differences seen in studies that asked about longer-term changes. Our February and April surveys had found counterparts on a much more immediate, tangible scale.

Fig. 1

Although the February and April 2016 results fit with broader patterns, they were not overwhelming by themselves. Believing in the value of replication, we asked the question one more time on a July 2016 survey, with winter several months behind. Most people still recalled the unseasonable warmth. Our July wording and results are as follows:

Thinking back to earlier this year, would you say that THIS PAST WINTER, the weather where you live was generally colder, warmer, or about average for winter in your area? ROTATE 1–3

1          Colder than average winter for your area (4%)
2          Warmer than average winter for your area
3          About average winter for your area
98        DK/NA (4%)

Political and climate-belief gaps now appeared wider than they had been earlier in the year. Figure 2 shows one striking example: a 21-point gap between supporters of Clinton and Trump (this was, after all, primarily a political poll).

Fig. 2Figure 3 breaks down the percentage of “warmer” responses on the July survey by other respondent characteristics, including their beliefs about climate change. P-values summarize tests from probability-weighted logit regression.

Fig. 3One notable pattern in Figure 3 involves political identification; we see a 17-point gradient from Tea Party supporters to Democrats in recollections about the winter they had all just experienced. Climate-change beliefs produce wider differences: respondents who don’t believe that climate is changing, or that climate is changing but for natural reasons, were much less likely to recall the warm winter.

Figure 4 places this July poll in context with political gradients (using the same 4-party scheme) from five previous surveys that asked longer-term climate/weather questions. Panels (a) and (b) involve atmospheric CO2 levels and Arctic sea ice (Hamilton 2012, 2015). Panels (c) and (d) depict results from two Northeast Oregon surveys that asked whether summers there had become warmer in the past two decades (Hamilton et al. 2016). Panel (e) charts responses to a question about whether flooding in New Hampshire had increased over the past decade (Hamilton et al. in press). Panel (f) repeats the unpublished July survey results described earlier, on whether New Hampshire’s recent winter had been warm.

Fig. 4What underlies this replicable pattern? Atmospheric CO2 levels and Arctic sea ice are not directly experienced by most people. They are measured and communicated mainly by scientists, so public resistance to these well-observed realities might be conceived as a problem of science communication, highlighting the need for ideologically-tailored methods. But science communication on these topics already involves many different organizations, research teams, and individual scientists taking diverse and ofttimes innovative approaches. An alternative hypothesis is that the partisan gradients reflect not shortcomings of science communication but the efficacy of counter-science communication, convincing ideologically receptive audiences that undisputed facts are false. The sociological literature about such counter-messaging has recently been summarized by Dunlap and McCright (2015).

Science communication seems distant, moreover, from panels c–f, which involve phenomena that can be directly experienced. Warmer, dryer summers in Northeast Oregon have exacerbated insect and disease threats to forests, both directly and indirectly contributing to the frequency of large wildfires. Such changes are visible, and in isolation seem equally compatible with individual beliefs that climate is change is happening either for natural or anthropogenic reasons — which together comprise 85% of the respondents in both Oregon surveys. Nevertheless, we find steep political gradients. Similar observations apply to flooding in New Hampshire, which has caused significant damage, and is most salient not through scientific reports but through news coverage if not personal experience. Again, most news coverage made no explicit connections with climate change, and most people (89% on these surveys) agreed anyway that climate is changing, whether from human or natural causes.

Although wildfires and floods might not impact everyone, or impress them with decadal change, the snowiness or un-snowiness of a winter affects daily life for just about everyone living in New Hampshire. Panel f depicts ideology-influenced perceptions at the mundane scale of recent weather.


Dunlap, R.E. & A.M. McCright. 2015. “Challenging climate change: The denial countermovement.” Pp. 300–332 in R.E. Dunlap & R.J. Brulle (eds), Climate Change and Society: Sociological Perspectives. New York: Oxford University Press.

Hamilton, L.C. 2012. “Did the Arctic ice recover? Demographics of true and false climate facts.” Weather, Climate, and Society 4(4):236–249. doi: 10.1175/WCAS-D-12-00008.1

Hamilton, L.C. 2015. “Polar facts in the age of polarization.” Polar Geography 38(2):89–106. doi: 10.1080/1088937X.2015.1051158

Hamilton, L.C., J. Hartter, B.D. Keim, A.E. Boag, M.W. Palace, F.R. Stevens & M.J. Ducey. 2016. “Wildfire, climate, and perceptions in northeast Oregon.” Regional Environmental Change doi: 10.1007/s10113-015-0914-y

Hamilton, L.C. & M. Lemcke-Stampone. 2016. “Was December warm? Family, politics, and recollections of weather.” Durham, NH: Carsey School of Public Policy.

Hamilton, L.C., C.P. Wake, J. Hartter, T.G. Safford & A. Puchlopek. in press. “Flood realities, perceptions, and the depth of divisions on climate.” Sociology doi: 10.1177/0038038516648547



Science curiosity vs. politically motivated reasoning: An experimental steel cage match!

So today I’ll finally tell you what we did in the information-seeking experiment featured in our new paper “Science Curiosity and Political Information Processing.”

It was pretty darn simple.

We assigned subjects to one of two conditions. In each, subjects were presented with two news story headlines: a “climate realist” one, which announced that scientists had uncovered evidence consistent with human-caused climate change; and a “climate skeptical” one, which announced that scientists had uncovered evidence that qualified or called into question the human contribution to climate change.

The difference in the conditions concerned the relative novelty of the opposing pieces of scientific evidence being featured in the respective headlines.

Thus, in Condition 1—“Realist unsurprising, Skeptical surprising”—the  respective newspaper headlines were “Scientists Find Still More Evidence that Global Warming Actually Slowed in Last Decade” and “Scientists Report Surprising evidence: Arctic Ice Melting Even Faster Than Expected.”

In contrast, in Condition 2—“Realist surprising, Skeptical unsurprising” condition—the respective headlines read, “Scientists Report Surprising Evidence: Ice Increasing in Antarctic, Not Currently Contributing To Sea Level Rise” and “Scientists Find Still More Evidence Linking Global Warming to Extreme Weather.”

Subjects were instructed to “pick the story most interesting to you,” and told they’d be asked some questions after they finished reading it.

Aversion to “counterattitudinal” information—that is, information that is contrary to one’s political outlooks—is one of the incidences of politically motivated reasoning.  When given the option, partisans tend to seek out information that is consistent with their predispositions rather than information that is contrary to them (Hart, Albarracín et al. 2009).

That’s exactly what we observed among subjects who were relatively low in science curiosity.

Among subjects who were relatively high in science curiosity, however, we saw the opposite effect.  Thus, relatively right-leaning science-curious subjects—who tended to be climate skeptical—nevertheless preferred the novel or “surprising” realist news story over the unsurprising skeptical story.

Likewise, relatively left-leaning science-curious subjects—who tended to be climate concerned—preferred the surprising skeptical story over the unsurprising realist one.

The effect sizes, moreover, were quite large: moderately science curious subjects were on average 32-percentage points (± 19, LC = 0.95) more likely to select the story that was contrary to their political predispositions than were moderate science incurious ones.

We are motivated to investigate this hypothesis by an unexpected observation in our “science of science filmmaking” studies.  As subjects’ science curiosity increased, their perceptions of contentious risks tended to move in the same direction. Moreover, high-curiosity subjects seemed to resist the normal tendency of individuals to polarize as their proficiency in science comprehension increased. 

We surmised that these individuals might be indulging their appetite for surprise by more readily examining evidence that contravened their political predispositions.  Being exposed to a greater volume of “counterattitudinal data,” they’d form views that were more uniform, and less prone to polarization conditional on science comprehension.

The experiment results supported this hypothesis.

Does this “prove” that science curiosity negates politically motivated reasoning?


It’s a mistake to think empirical evidence ever proves anything

What it does, if it is the product of a valid design, is furnish more reason than one otherwise would have had for crediting one competing account of some phenomenon over another. 

As I explained yesterday, the hypothesis that that science curiosity offsets politically motivated reasoning, is a plausible conjecture—but so is the hypothesis that science curiosity, like other cognitive elements of science comprehension, magnifies this biased form of information processing.

On the scale that registers the strength of the evidence for these respective hypotheses, the experiment result puts an increment of weight down on the side of the first hypothesis.

How much weight?

Well, you can decide that!

But if you are curious for our own views, read the paper: It catalogs our own qualifications and sources of residual uncertainty—and outlines a set of questions for further investigation.

We’re really curious to see if this result stands up to even more critical testing!


Hart, W., Albarracín, D., Eagly, A.H., Brechan, I., Lindberg, M.J. & Merrill, L. Feeling validated versus being correct: a meta-analysis of selective exposure to information. Psychological Bulletin 135, 555-588 (2009).

Kahan, D.M., Landrum, A.R., Carpenter, K., Helft, L. & Jamieson, K.H. Science Curiosity and Political Information Processing. Advances in Political Psychology  (in press).


Science curiosity & politically biased information processing--the (inevitable!) OCTUSW response

OKay, yesterday I promised to say more about the information-exposure experiment we conducted to test the conjecture that “science curiosity” tends to negate politically biased information processing.

Maybe first though I should say something about why this sort of result isn’t an obvious one.

Or actually why it is is obvious-- but why a result the other way would have been obvious, too!

The best studies, in my view, are ones that test opposing plausible conjectures.  This is the upshot of the “more things are plausible than are true” principle, which I attribute to Duncan Watts (2011).

It’s the premise, basically, of his cool book “Everything is Obvious: Once you know the Answer.”  Because more explanations for interesting social phenomena are plausible than are actually true, if one doesn’t use empirical methods to extricate the true (or more likely true) from the sea of plausible but false explanations, one drowns in a sea of just-so story-telling.

But of course, once one does the work of presenting valid empirical evidence that furnishes more reason to believe one plausible conjecture rather than its rival, someone will inevitably trot out the boring  OCTUSW--"Of course--that's unsurprising--so what"—response. 

To which the answer is, YAIIFTOTBTTWHBEO!, or “Yup; and if I’d found the opposite to be true, that would have been equally ‘obvious’! Aren’t you glad, then, that I actually went to the trouble of trying to generate some actual evidence instead of just lazily taking a bunch of plausible behavioral mechanisms, adding water & stirring—to produce the instant pseudo-science profundity that passes for decision science in op-ed pages & best-selling books?”

Indeed, I make a point of doing only studies about which someone could say, "Of course, that's unsurprising so what" no matter which way the study result comes out

But by the time you say all  this, of course, Mr. or MS OCTUSW has moved on to some other topic about which he or she can make this or some equally penetrating remark.


Why would a result the opposite of what we found—viz., that highly science curious individuals, unlike less curious ones, willingly expose themselves to evidence that confounds their political predispositions—not have been particularly surprising?

The answer is “motivated system 2 reasoning” – or MS2R.

MS2R refers to the tendency of the reasoning proficiencies associated with science comprehension to magnify rather than abate politically motivated reasoning (PMR)—the tendency to conform evidence to one’s political predispositions. 

Cognitive reflection, numeracy, science literacy—they all do that (Kahan in press).

Does that outcome seem obvious, too?


But the opposite effect—the tendency of proficiency in these sorts of reasoning abilities to temper political polarization—certainly is plausible, and any evidence that they do would certainly have been “obvious—once one knew the answer.”

Most cognitive biases—from base rate neglect to the availability heuristic, from ratio bias to the conjunction fallacy—reflect an overreliance on the rapid, intuitive, affect-driven “System 1” information processing as opposed to the more deliberative, conscious, dispassionate “System 2” kind characteristic of good “scientific” reasoning.

PMR compromises truth-convergent Bayesian reasoning in a manner akin to these biases. So why wouldn’t one expect it, too, to be attributable to overreliance on heuristic, system 1 reasoning ?


But false.  Tons of observational & experimental data at this point show that cognitive reflection, numeracy, science literacy, etc.,  are all associated with greater political polarization.

Under the conditions that generate PMR, people use their science-comprehension reasoning proficiencies to reinforce their biased assimilation of evidence to the position that coheres with their political predispositions.

That’s MS2R!

Now science curiosity—just like cognitive reflection, numeracy, knowledge of basic science facts, etc.—is cognitive element of science comprehension.

I went over this in a post a couple of days ago that showed  that people high in science curiosity are significantly more likely to be high in science comprehension than are those who are low in science curiosity.

Can you see now why it would have been perfectly plausible to surmise—and perfectly obvious to find—that science curiosity, like these other elements of science comprehension, magnify political polarization?

But there’s a perfectly respectable conjecture the other way: that unlike these other elements of science comprehension, science curiosity involves an appetite to be surprised—to experience the awe and wonder of contemplating surprising insights derived from the signature methods of science.  Maybe the habitual exercise of that disposition develops habits of mind that counteract rather than accentuate PMR.

Maybe! Or maybe not!

Only one way to tell . . . . Do a valid empirical study.

Oh-- & then do another, & another & another –and progressively update one’s views on the respective probability of these two perfectly plausible hypotheses—viz., science curiosity amplifies & science curiosity mitigates PMR.

So there you go, Mr./MS. OCTUSW.

We are now ready to (re)turn to the more interesting question: what was the evidence we relied on and how much reason does it give us to credit the “science curiosity mitigates” PMR hypotheses.

But I've said enough for one day, so  I’ll have to do that “tomorrow.”

Again, though, if your insides are being consumed by curiosity on the experiment design and results, don't suffer--just download our paper & read it . . . . right now!


Kahan, D.M. The Politically Motivated Reasoning ParadigmEmerging Trends in Social & Behavioral Sciences, (in press_b),

Kahan, D.M., Landrum, A.R., Carpenter, K., Helft, L. & Jamieson, K.H. Science Curiosity and Political Information Processing. Advances in Political Psychology  (in press).

Watts, D.J. Everything is Obvious: Once You Know the Answer: How Common Sense Fails (Atlantic Books, 2011).



Science curiosity & climate change (de)polarization (new paper)

Consider four propositions of ascending curiousness.

  1. Increasing science curiosity is associated with greater acceptance of human-caused climate change in the general population.

  2. This effect holds regardless of political outlooks

  3. Increasing science curiosity counteracts the association between increased science comprehension and and political polarization on societal risks such as climate change and fracking.

  4. As science curiosity goes up, individuals of all political outlooks become more interested in engaging information contrary to their political predispositions on climate change.

Proposition (1) is kind of interesting, but until it is combined with proposition (2), it doesn’t tell one much of anything.  A population-wide association between some disposition and a belief or attitude is interesting only if there isn’t significant variation in that relationship among different sorts of people. If there is, then the population-wide effect obscures that and invites specious inferences about how the disposition in question influences the relevant belief or attitude.

Let’s call the class of specious inferences the “Pat” fallacy: because “Pat," who is “average” along every conceivable dimension, doesn’t exist, it is a meaningless exercise to treat how some disposition in “Pat” affects “Pat’s” beliefs, attitudes, etc., if in fact relevant dimensions of identity affect the relationship of the disposition to beliefs, attitudes, etc., in real-life, truly existing people.

Click me! I'm the best image in this post!But once we know that there is a uniform relationship between some disposition and some belief or attitude (or one that is uniform in relation to some meaningful aspect of individuals' identities), then we can start to assess the significance of that.

The clue to the significance here is revealed by (3).  We know (because it’s been shown 15x10^3 times) that pretty much every conceivable reasoning disposition relevant to science comprehension magnifies rather than ameliorates political polarization on societal risks.  That happens because where positions on a risk or like fact become badges of membership in and loyalty to one or another tribal group, people will face strong psychic pressure to use their reasoning proficiencies to filter information in a manner that promotes their beliefs to the ones that that predominate in their groups.

Science curiosity is a reasoning disposition that can reasonably be understood to be integral to science comprehension. So one might expect it to magnify polarization on issues like climate change, too.

No! Don't listen to her! I'm the best image! Click me!!!!But it doesn’t. It has the opposite effect!

Why? Why?? Why???

This is the question that the 14 billion readers of this blog were left to grapple with about 5 mos ago when propositions 1-3, which were observed in Study No. 1 of the Cultural Cognition Project/Annenberg Public Policy Center “Science of Science Filmmaking Initiative.”

One conjecture was that science-curious individuals might be using their reason in a way that counteracts the usual consequences of politically motivated reasoning (PMR). 

Generally speaking, PMR is associated with biased information search: that is, partisans tend not only to fit their assessments of information to their predispositions, but to focus their attention on information sources that can be expected to confirm rather than challenge the positions that cohere with their political outlooks (Hart, Albarracín, et al. 2009)..

But scientifically curious people have an appetite to be surprised by the insights generated by the use of science’s signature methods of disciplined observation, measurement, and inference.  That appetite might impel them, unconsciously, to expose themselves more readily than their less curious political peers to expose themselves to information that is contrary to their predispositions.  If so, they might end up with perceptions of risk that are at least a bit closer to those of their political opposites who are scientifically curious and who are doing the same thing.

That was the animating hypothesis of an experiment, the outcome of which is the basis of proposition 4.  In that experiment, we—my collaborators at CCP and APPC—tested just how readily partisans would expose themselves to surprising scientific evidence on climate change when that evidence was contrary to their political predispositions (Kahan, Landrum, Carpenter, Helft & Jamieson in press).

Absurd! I'm clearly the coolest image in this post. Click me, or I'll destroy the entire internet!!!We found that individuals who were low to moderate in curiosity wouldn’t do it. They opted for “familiar” evidence supportive of the position associated with their own political outlooks.

But highly curious subjects behaved differently. Confronted with the chance to peruse some surprising evidence that challenged their existing views, they went for it.

I guess they just couldn’t resist!

What exactly did we do to elicit this observation? Well, I’ll tell you about that “tomorrow.”

Or if you are just so curious you can’t wait until then, you can check out our new CCP/APPC Science of Science Communication Initiative paper, “Science Curiosity and Political Information Processing” for details!


Hart, W., Albarracín, D., Eagly, A.H., Brechan, I., Lindberg, M.J. & Merrill, L. Feeling validated versus being correct: a meta-analysis of selective exposure to information. Psychological bulletin 135, 555 (2009).

Kahan, D.M., Landrum, A.R., Carpenter, K., Helft, L. & Jamieson, K.H. Science Curiosity and Political Information Processing. Advances in Political Psychology  (in press).


"Mirror mirror on the wall ... who is the most partisan of all?!" MAPKIA Episode No. 978!

Hey, everybody, I think you know what it's time for . . . .

That’s right-- another episode of Macau's favorite game show...: "Make a prediction, know it all!," or "MAPKIA!"!

To get the technicalities out of the way, here's the posting of the "official statement of contest terms & conditions,"  as mandated by the Gaming Commission:

I, the host, will identify an empirical question -- or perhaps a set of related questions -- that can be answered with CCP data. Then, you, the players, will make predictions and explain the basis for them. The answer will be posted "tomorrow." The first contestant who makes the right prediction will win a really cool CCP prize (like maybe this or possibly some other equally cool thing), so long as the prediction rests on a cogent theoretical foundation. (Cogency will be judged, of course, by a panel of experts.)

Okay, this is a tricky one!

It’s going to take (a) a Feynmanite/Selbstian level of analytical thought, (b) a Fredrickian resistance to the seductive tug of WEKS, plus (c) a Barry-Bonds-sized dose of political-psychology HGH (& yes former Freud expert & current stats legend Andrew Gelman and Josh " 'Hot Hand Fallay' Fallacy" Miller both remain eligible for this MAPKIA pending their appeals for testing positive in the aftermath of their stunning post “CCP-APPC Political Polarization IQ Test”™ victories).

Let’s start by creating a “political partisanship index.”  The recipe for that is as follows:

  1. Take a left-right political outlook scale formed by standardizing the sum of the sums of responses to conventional 7-point political-party identification and 5-point liberal-conservative ideology survey items. A very nice feature of this approach when one uses it with a nationally representative sample is that “0” is “moderate Independent,” while -1 and +1 SD are “liberal Democrat” and “conservative Republican,” respectively. Scores in the vicinity of -1.8 and +1.8 will be “Extremely liberal, Strong Democrat” and “Extremely conservative, Strong Republican,” respectively. In case you’ve forgotten how nicely this simple scale performs in picking in partisan polarization on contested issues, check out the policy-polarization figure below or watch a re-run of the wildly popular episode on the “CCP-APPC PPQ IQ Test”™).

  2. Then take the absolute value of the scores on this Left_right scale. The result is a “Partisanship Index” (PI), one that registers the intensity of one’s left-right outlooks without regard to their valence. Thus, if one is either a “liberal Democrat” or a “conservative Republican,” one gets a PI score of “1.0.” If one is either an “Extremely liberal, Strong Democrat” and “Exremely conservative, Strong Republican,” one gets a PI score of 1.8. A milqetoast politically sissy who is a “moderate Independent” will get a score of “0.”

Okay, got that?  Good. (If you are curious for what the relationshop between Left_right and PI looks like without smoothing--and why the intercept for zero on y axis is slightly above zero--good for you! Click here).

Now here is the MAPKIA question:

What is the profile of a “super partisan”? On the basis of characteristics like (a) gender, (b) race, (c) income, (d) education, (e) science comprehension (measured by OSI), (f) science curiosity (measured with SCS), (g) religiosity, (h) cultural worldivews (measured with the CCW scales) etc. or appropriate combinations thereof, who is the most partisan “type” of person (i.e., gets the highest PI score) in U.S. society????

You know the rules: don’t just gesture toward an answer in some vague discursive way; be specific, both about what your conjecture and why, and tell me how to test it using the sort of data that typically appears in a CCP data set.

Realize that basically the question is, What's the relationship between the specified characteristics and partisanship? If you want to specificy simple correlations between partisanship and one or more of these attributes or (better still)  combinations of them, that's fine!

But if you have some more clever way to specify how the characteristics should be combined into some latent-variable "identity" variable or how the relationship between the characteristics (individually or in combination) should be related to the Partisanship index (in that regard, you might want to check out "yesterday's" post on how science curiosity and science comprehension relate to each other), go for it!

Now, an important proviso: Do not tell me to just jam every one of these characteristics onto the right hand side of a goddam linear regression and “see what comes out statistically significant.”  The reason  is that the results of such an analysis will be gibberish. 

Actually, the R2  will be fine & might be interesting if you want to get an idea of the the upper limit of the possibilities for explaining PI. But the parameter estimates will be meaningless in relation to our task, which is to identify the sorts of real-world people who are super partisans. 

And with that . . . mark, get set, MAPKIA! 


What is the relationship between science curiosity & science comprehension? A fragment . . .

From something I’m woring on (and useful refinement of this discussion of how to think about size of individual differences in one or another reasoning disposition). . .

c. Compared to ordinary science intelligence. Science curiosity—generally or as measured here—ought to be have some relationship to science comprehension. It is difficult to experience the pleasure of contemplating scientific insight if one is utterly devoid of any capacity for making sense of scientific evidence. Similarly, if one is aggressively uncurious about scientific insights, one is less likely to acquire the knowledge or the experience-based habits of mind to reason well about scientific insights.

Yet the two dispositons shouldn’t be viewed as one and the same.  Many people who can detect covariances and successfully compute conditional probailities—analytical tasks essential to making sense of empirical evidence—are nevertheless uninterested in science for its own sake.  Even more obvious, many people who are only modestly proficient in these technical aspects of assessing empirical evidence are interested—passionate even—about science. In sum, one would expect a science-curiosity measure, if valid, to be modestly correlated with but definitey not equivalent to a valid science comprhension measure.

SCS, the science-curious measure we formed (Kahan, Landrum & Carpenter 2015), has these properties.  The association between SCS and the Ordinary Science Intelligence (OSI) assessment (Kahan 2016) was r = 0.26 in our two data collections. To make this effect more practically meaningful,

SCS has these properties.  The association between SCS and the Ordinary Science Intelligence (OSI) assessment (Kahan 2016) was r = 0.26 in our two data collections. To make this effect more practically meaningful, the relationship between these measures implies that that individuals in the top quartile of SCS are over four times more likely than those in the bottom quartile to score in 90th percentile or above on the OSI assessment (Figure 6).  This is a degree of association consistent with the expectation that higher science curiosity contributes materially to higher science comprehension. Nevertheless, in both studies science comprehension lacked meaningful predictive power in relation to engagement with the three science videos featured in our two studies (Figure 7). In other words, SCS measures a disposition that is apparently integral to the kind of proficiency in scientific reasoning measured by OSI, yet generates a form of behavior—the self-motivated consumption of science information for its own sake—that is unassociated with science comprehension by itself.


Kahan, D.M. ‘Ordinary science intelligence’: a science-comprehension measure for study of risk and science communication, with notes on evolution and climate change. J Risk Res. (2016), advance on line at 

Kahan, D., Landrum, A. & Carpenter C. Evidence-based Science Filmmaking Initiative, Study No. 1 (2015), at





What antagonistic memes look like: the case of the HPV Vaccine

From the new APPC/CCP Working Paper, Culturally Antagonistic Memes & the Zika Virus

2.1. In general

* * *

“Memes” refer to ideas and practices that enjoy wide circulation and arouse self-reinforcing forms of attention as well as spontaneous adaptation and elaboration (Balkin 1998; Blackmore 1999). A small subset of these sorts self-replicating ideas and practices, the ones we call “culturally antagonistic memes” refer to highly evocative, highly inflammatory argumentative tropes used by members of one group to stigmatize another.

When they figure in debates over risk, these contempt-pervaded tropes invest positions on them with affective resonances symbolic of opposing groups’ values or identities.  In the resulting discourse climate, individuals will come to perceive risk regulation as “express[ing] the public worth of one subculture’s norms relative to those of others, demonstrating which cultures have legitimacy and public domination” and thereby “enhnanc[ing] the social status of groups carrying the affirmed culture and degrad[ing] groups carrying that which is condemned as deviant” (Gusfield 1968, p. 59). Conducted in the idiom of instrumental consequences, the stances diverse citizens adopt on which activities genuinely threaten society and which policies truly mitigate the attendant dangers are become rhetorical subterfuges in an “ongoing debate about the ideal society” (Douglas &Wildavsky 1982, p. 36). 

This process is effected through a decisive switch in the sort of information processing that is characteristic of the AH-CCT model. From a reliable and consensus-generating guide to valid decision relevant-science, the affective heuristic and cultural cognition at this point combine to generate a divisive, nontruth-convergent source of identity-protective cognition (Sherman & Cohen 2002; Kahan 2010).

By fusing contending positions on a risk or like facts to opposing group identities, antagonistic memes effectively transform positions on them into badges of membership in, and loyalty to, competing groups. Because this state of affairs pits opposing groups’ knowledge-certification systems against one another, the forms of information-processing associated with cultural cognition and the affect heuristic will under these conditions necessarily lose their power to generate truth-convergent forms of consensus across them.

This switch will not cause such information processing to abate, however.  There is rarely any personal action that an individual can take that will affect the level of danger that a societal risk poses to him or anyone he cares about; his decisions as a consumer, voter, or participant in public debate won’t matter enough, for example, to affect the course of climate change, or the regulation of fracking, or the siting of nuclear waste facility.  In contrast, such an individual’s personal behavior, including the attitudes he evinces on issues infused with social meanings, will typically have tremendous significance for the impressions that others form of his character (Sherman & Cohen 2002; Lessig 1996).  As a result, it will be individually rational, if collectively disastrous, for individuals to form habits of mind that reliably produce identity-affirming rather than accurate ones when societal risks become infused with meanings that divide their groups from others (Kahan 2015b).  

Hi, it's me again! Click me to say hello!Indeed, these habits of mind will become seamlessly interwoven into the capacities essential for assessing scientific information. “Motivated system 2 reasoning” refers to the tendency of individuals to use their proficiency in Numeracy, cognitive reflection, and science comprehension to ferret out and credit identity-congruent evidence and explain away the rest (Kahan in press_b).  Much as a virus does to the genetic material of an otherwise healthy cell, identity protective cognition effectively insinuates itself into reasoning dispositions essential to recognizing the best available evidence (Kahan 2013; Kahan, Peters et al.  2013).  Their cognitive faculties having been redirected in this fashion, the individuals most adept in these forms of reasoning will end up the most polarized on culturally contentions risks (Hamilton 2011, 2012; Kahan, Peters et al..  2012).

Identity-protective cognition is thus not a not a natural outgrowth of but rather a pathological deformation of the processes associated with the AH-CT model. The trigger of this pathology, moreover, is the advent of culturally antagonistic memes (Figure 1).

2.2. A concrete illustration

Many persistently contested science issues fit this pattern.  But we will focus on one that we believe is particularly well suited for illustration: the U.S. experience with the HPV vaccine.

I dare you: click me!

The HPV vaccine confers (near-perfect) immunity to the human papilloma virus, an extremely common s

exually transmitted disease that cause cervical cancer.  The vaccine also has the distinction of being the only childhood immunization recommended for universal administration by the U.S. Centers for Disease Control that is not now on the schedule of mandatory school-enrollment immunizations in the United States.  Legislative proposals to add it were defeated in dozens of states in the years from 2007 to 2008 as a result of intense political controversy over the safety and effectiveness of the vaccine (Kahan 2013).

Although the proposal to add the HPV vaccine to the list of mandatory vaccinations divided the public along predictable lines, the conflict over it was in fact not inevitable.  Only a few years before nearly every state had endorsed the CDC’s proposal for universal administration of the HBV vaccine, which likewise confers immunity for a sexually transmitted disease, hepatitis-b, that causes cancer (of the liver).  The HBV vaccine is now given in infancy, but at that time it was an adolescent shot, just like the HPV vaccine.  During the years in which legislative battles were raging over the latter vaccine, nationwide vaccination rates for the former were well over 90% (ibid).

Like every other childhood vaccine that preceded it, the HBV vaccine was considered and approved for inclusion in state universal-immunization schedules by non-political public health agencies delegated this expert task by state legislatures.  The vast majority of parents thus learned of the vaccine for the first

time when consent to administer it was sought from their pediatricians, trusted experts who advised them the vaccine was a safe addition to the array of prophylactic treatments for keeping their children healthy.  Just as important, regardless of who these parents were—Republican or Democrat, devout evangelical or atheist—they were all afforded ample evidence that parents just like them were getting their kids vaccinated for HBV.  This is a science communication environment in which the AH-CCT model can be expected to generate largely convergent affective reactions across all groups—exactly the outcome that was observed.

The HPV’s vaccine path to public awareness, in contrast, was much more treacherous. Seeking to establish a dominant position in the market before the approval of a competing shot, the manufacturer of the HPV vaccine  orchestrated a nationwide campaign to establish immunization mandates by statutes enacted by state legislatures.  What was normally a routine, nonpolitical decision—the administrative updating of states’ mandatory-vaccination immunization schedules—thus became a high-profile, highly partisan dispute.  People became acquainted with the vaccine not during visits to their pediatricians’ office but while viewing Fox News, MSNBC, and other political news outlets. There they were bombarded with reports on the “slut shot” (Taormino 2006) and “virgin vaccine” (Page 2006) for school girls, a framing enabled by the manufacturer’s decision to seek fast-track FDA approval of a women’s-only shot as part of company’s plan to vault over the conventional, less speedy, depoliticized administrative-approval process (Gollust, Lorusso et al.  2015).

These media stories and resulting social media reaction were replete with what we are referring to as “culturally antagonistic memes.”  “Trust us: Vioxx, Now Gardasil,” declared a viral internet feature that mocked the manufacturer’s own advertising campaign (Figure 2). “HPV vaccine: Republicans prove themselves morons once again,” sneered liberal commentators (2011). “They value your virginity more than your life,” another righteously intoned; “there was a time when only the loony left believed that the loony right favored death over sex; not any more” (Goodman 2005).  Individualist-oriented commentators retorted: “Let’s use teenage girls as lab rats for a monopoly” (Erickson 2011).

These are exactly the conditions one would expect to fuse a risk issue to antagonistic social meanings, thereby triggering identity-protective cognition on the vaccine’s risks and benefits (Fowler & Gollust 2015; Bolsen, Druckman & Cook 2013).  Studies confirmed that exactly that happened (Gollust, Dempsey et al.  2010; Kahan et al.  2010).


“HPV Vaccine: Republicans Prove Themselves Morons Once Again.” Why Evolution Is True. (Sept. 14, 2011).

Bolsen, T., Druckman, J.  & Cook, F.L.  The effects of the politicization of science on public support for emergent technologies.  Institute for Policy Research Northwestern University Working Paper Series (2013).

Bolsen, T., Druckman, J.N.  & Cook, F.L.  The influence of partisan motivated reasoning on public opinion.  Political Behav. 36, 235-262 (2014).

Bolsen, T., Druckman, J.N. & Cook, F.L. Citizens’, scientists’, and policy advisors’ beliefs about global warming. The ANNALS of the American Academy of Political and Social Science 658, 271-295 (2015).

Douglas, M. & Wildavsky, A.B. Risk and Culture: An Essay on the Selection of Technical and Environmental Dangers (University of California Press, Berkeley, 1982).

Douglas, M. Purity and Danger: An Analysis of Concepts of Pollution and Taboo (1966).

Druckman, J.N. & Bolsen, T. Framing, Motivated Reasoning, and Opinions About Emergent Technologies. Journal of Communication 61, 659-688 (2011).

Erickson, Erick. Let’s Use Teenage Grils as Lab Rats for a Monopoly. RedSate. (Aug. 17, 2011), at

Fowler, E.F. & Gollust, S.E. The content and effect of politicized health controversies. The ANNALS of the American Academy of Political and Social Science 658, 155-171 (2015).

Gollust, S.E., Dempsey, A.F., Lantz, P.M., Ubel, P.A. & Fowler, E.F. Controversy undermines support for state mandates on the human papillomavirus vaccine. Health Affair 29, 2041-2046 (2010).

Gollust, S.E., LoRusso, S.M., Nagler, R.H. & Fowler, E.F. Understanding the role of the news media in HPV vaccine uptake in the United States: Synthesis and commentary. Human Vaccines & Immunotherapeutics, 1-5 (2015).

Goodman, Ellen. Abstinance-only crowd laments cancern breakthrough. Boston Globe. (Nov. 14, 2005), at

Gusfield, J.R. On Legislating Morals: The Symbolic Process of Designating Deviance. Cal. L. Rev. 56, 54 (1968).

Hamilton, L.C. Education, politics and opinions about climate change evidence for interaction effects. Climatic Change 104, 231-242 (2011).

Hamilton, L.C., Cutler, M.J. & Schaefer, A. Public knowledge and concern about polar-region warming. Polar Geography 35, 155-168 (2012). 

Kahan, D. Fixing the Communications Failure. Nature 463, 296-297 (2010).

Kahan, D., Braman, D., Cohen, G., Gastil, J. & Slovic, P. Who Fears the HPV Vaccine, Who Doesn’t, and Why? An Experimental Study of the Mechanisms of Cultural Cognition. Law Human Behav 34, 501-516 (2010).

Kahan, D.M. A Risky Science Communication Environment for Vaccines. Science 342, 53-54 (2013b).

Page, Christina. The Virgin Vaccine. Nerve. (June 28, 2006), at

Sherman, D.K. & Cohen, G.L. Accepting threatening information: Self-affirmation and the reduction of defensive biases. Current Directions in Psychological Science 11, 119-123 (2002).

Taormino, Tristan. The Slut Shot. Village Voice., (Aug. 15, 2006), at





What antagonistic memes look like: the case of the Zika virus

From the new APPC/CCP Working Paper, Culturally Antagonistic Memes & the Zika Virus:

3.1. Why Zika

The focus of the study was the impact of culturally antagonistic-meme generating communications on the perceived risks of the Zika virus.

We selected the Zika virus for two reasons. The first is that we are confident there isn’t currently meaningful cultural dissensus on Zika at the current time. For over five months, the Annenberg Public Policy Center (2016a) has been tracking U.S. public opinion on the disease. Attention early on spiked and then leveled off, and is now rising again; knowledge about the health effects of the virus and about effective means of self-protection have proven uneven; certain misunderstandings about the link between the virus and microcephaly have persisted, albeit at modest levels (Annenberg Public Policy Center 2016b).

But nothing in this mix varies meaningfully with ideology, religion, or like forms of cultural identity.  There is reason to be apprehensive about the speed with which members of the public are progressing in their understanding of key facts about the virus. But the evidence suggests that culturally diverse members of the public are progressing in unison, much in the manner one would expect under the “normal,” nonpathological process contemplated by the AH-CCT Model (Figure 1).

click me-- more refreshing than a cold lemonaid in the middle of an AGW heatwave!At the same time, there has been a steady accumulation of communications tying the Zika health threat to already culturally charged issues (Figure 3).  The voice of public health officials furnishing the public with precautionary advice is only one in a chorus, whose other members include a collection of advocacy groups all seeking to leverage public anxiety over Zika into greater attention to their special cause.

Among these are anti-immigrant groups. These actors suggest that the spread of Zika is likely to be accelerated by undocumented aliens as well as lawful immigrants from Zika-affected regions. “Latin America’s Zika virus is the latest undocumented immigrant to hit our shores,” one commentator caustically notes (Malkin 2016). It’s obvious from the “available evidence” that “open borders contribute to the vulnerability of the United States to the virus” (Corsi 2016). “People from Central and South America, ground zero for Zika and other infectious diseases including tuberculosis, dengue, Chagas, Chikungunya and schistosomiasis, make up nearly 15 percent of the illegal-immigrant population in the U.S.” (Malkin 2016). “[A] drain on our economy, a peril to our national security, and a drag on our souls,” illegal immigrants are now “hazardous to our health, thanks to sloppy U.S. immigration laws acting as incubators for diseases once foreign to North America — like the untreatable Zika virus” (Abruzzo 2016).

Climate change advocates have also latched onto Zika. “Zika is the kind of thing we’ve been ranting about for 20 years,” one observes. “We should’ve anticipated it. Whenever the planet has faced a major climate change event, man-made or not, species have moved around and their pathogens have come into contact with species with no resistance” (Milman 2016). Now “thanks to climate change” Zika could “soon enjoy a greater reach” (Mercer 2016), “spread[ing] deeper” into now secure areas of the U.S. (Gillis 2016).  Of all the “tragedies stemming from global warming,” including the “floods and droughts and storms, the failed harvests and forced migrations, . . . no single item on the list seems any more horrible than the emerging news from South America about the newly prominent Zika disease” (McKibben 2016). “We need to face up to the fact that pushing the limits of the planet’s ecology has become dangerous in novel ways.”  “The Republicans are in denial about climate change, but in the real world, we can feel it . . . . It’s also an invitation for breeding mosquitoes and putting Americans at risk all across the United States” (Johnson 2016).

The situation presented, then, furnishes an ideal one to extend previous research.  The tropes that inform advocacy material linking Zika to other culturally contested issues are replete with the accusatory and resentment-focusing tropes featured in highly polarized risk disputes. Yet in no  previous study  has there been an opportunity to test the impact of such tropes in relation to an issue not already the subject of at least modest contestation.

It is possible, of course, that the explanation for the patchwork of contestation and tranquility that forms the fabric of public risk perception is some as-yet undetected factor intrinsic to particular risk sources. It is perfectly plausible to believe, too, that deeper, historical influences render a particular risk source either impervious or distinctly amenable to controversy of a particular form, in particular societies. But through an appropriately constructed study, one can test the alternative hypothesis that it is the contingent advent of exposure to culturally antagonistic memes that triggers such conflict, and accounts for its complexion and intensity.  The study we conducted was aimed at furnishing evidence relevant to assessing the relative plausibility of these alternative conjectures.

click for closer look!Referances

Abruzzo, S.  Illegals, not American travelers, may be bringing Zika to our shores.  Brooklyn Daily (Feb.  5, 2016), available at

Annenberg Public Policy Center. Annenberg Science Knowledge Survey (2016a). Available at

Annenberg Public Policy Center. More than 4 in 10 Mistakenly Think Zika is Fatal, Symptoms are Noticeable. Annenberg Science Knowledge Survey (Mar. 10, 2016b). At

Corsi, J.  Zika Virus Joins List of Diseases Brought by Illegals.  WND (Feb.  1, 2016), available at

Gillis, J. In Zika Epidemic, a Warning on Climate Change. N.Y. Times, A6 (2016).

Johnson, B., Dem Leaders: Climate change stoking Zika, which could b ‘greater threat’ than Ebola. PJ Media. (Apr. 26, 2016), at

Malkin, M. Chicken Little Chuckie Schumer: America's Disease-Fighting Phony. National Review (Feb. 3, 2016), available at

Mercer, G. The Link Between Zika and Climate Change. Atlantic (2016).

Milman, O. Climate change may have helped spread Zika virus, according to WHO Scientists. Guardian (Feb. 11, 2016), at


New paper: Zika risk perceptions & culturally antagonistic memes!

Latest from the APPC/CCP "Science of scienc communication initiative working paper series" (previous installments include Kahan, D.M. ‘Ordinary science intelligence’: a science-comprehension measure for study of risk and science communication, with notes on evolution and climate change, J. Risk Res, 1-22 (2016), & Kahan, D.M. Climate-Science Communication and the Measurement Problem, Advances in Political Psychology 36, 1-43 (2015)). More on this paper "tomorrow."


Culturally Antagonistic Memes and the Zika Virus: An
Experimental Test


This paper examines a remedy for a defect in existing accounts of public risk perceptions. The accounts in question feature two dynamics: the affect heuristic, which emphasizes the impact of visceral feelings on information processing; and the cultural cognition thesis, which describes the tendency of individuals to form beliefs that reflect and reinforce their group commitments. The defect is the failure of these two dynamics, when combined, to explain the peculiar selectivity of public risk controversies: despite their intensity and disruptiveness, such controversies occur less frequently than the affect heuristic and the cultural cognition thesis seem to predict. To account for this aspect of public risk perceptions, the paper describes a model that adds the phenomenon of culturally antagonistic memes—argumentative tropes that fuse positions on risk with contested visions of the best life. Arising adventitiously, antagonistic memes transform affect and cultural cognition from consensus-generating, truth-convergent influences on information processing into conflictual, identity-protective ones. The paper supports this model with experimental results involving perceptions of the risk of the Zika virus: a general sample of U.S. subjects, whose members were not polarized when exposed to neutral information, formed culturally polarized affective reactions when exposed to information that was pervaded with antagonistic memes linking Zika to global warming; when exposed to comparable information linking Zika to unlawful immigration, the opposed affective stances of the subjects flipped in direction. Normative and prescriptive implications of these results are discussed.  


Download it, read it, improve it by comments!




Weekend update: Could Trump really win? What people do & don't *fear* says, "sure, why not?"


Why don't we have more gun control given that there is such overwhelming bipartisan public consensus in favor of that policy? WEKS strikes again . . .

So there have been a rash of news commentaries recently about “why” we don’t have more gun control given that there is overwhelming  “public support” for it.

I myself have offered explanations for this in the past.

But I’m wondering: is the premise really true? Is there really overwhelming public support for more gun control?

Or is this (like the “astonishing change in societal norms on gay marriage”) another instance of “WEKS” – “ ‘what everyone knows [is true]' syndrome,” the condition in which people with like-minded cultural outlooks convince themselves that “everyone” agrees with them on some issue that is in fact highly contested as a cultural matter?

Well, here’s some evidence for WEKS:

click for bigger viewAs the captions indicate, the data come from two separate APPC /CCP studies, one just concluded and the other from Jan.

They both show that gun control is not only massively polarizing but is among the most polarizing issue in American politial life—right up there with climate change and affirmative action.

The left-hand panel uses the tried-and-true Industrial Strength Risk Perception Meaure, which, as a result of the “affect heuristic” (Finucane, Alhakami, Slovic & Johnson 2000), magically encapuslates in one simple it the same level of covariance one would see when one relates the variable on the x-axis (here political outlooks) to any other more specific question that individuals would recognize as having to do with the risk in questin (e.g., on global warming, “is it happening,” “are humans causing it,” “are we all going to suffer horrendous harm as a result of it” etc).

It helps to show, then, that the proposition that there is as much polarization on guns—whether one frames the issue as one of the risks of allowing or not allowing people to have them—as there is on climate change, which is pretty much the most polarizing issue today (maybe ever) in American politics (there’s definitely a lot of “WEKS” on that, btw, although there is also the disturbing influence of attempts to “message” people with invalid surveys; maybe I’ll talk about that “tomorrow”).

click here for policy preference item wordingI put the right-hand panel in to help show that the sort of polarized affective responses look like when one cashes them out in terms of “policy positions.”

It shows, again, that proposals for stricter gun control laws have the same political-polarization profile as many of the issues we recognize as benchmarks of left-right factionalization.  I’ve also put in a couple of “non-polarized” issues just as a reference point (if you didn’t know vaccines were non-polarizing, you need to get out—of the WEKS bubble—more often).

Those data, again, are from Jan.

But another reason for putting in the left-hand side ISRPM panel is to help asnwer the question whether “something might have changed” given recent mass shooting.  Because the covariance from the ISRPM will always be nearly identical to the covariance on policy issues like this (for a miraclous proof of that propostion, check this out), we can be confident that if we are seeing the sort of ISRPM profile displayed in the left-hand panel, then we’d still see today the sort of division on “policy preferences,” or any other gun control question we might ask that people could actually understand.

So . . .

Why do so many people (but not all! there are plenty of people, it should be pointed out, who recognize gun control is polarizing) think there is consensus in the public for more gun control?

Like I said, I’ve definitely myself formed and expressed this impression myself!

But I do think it is almost certainly WEKS at work.  The people who say there is consensus for "more control" are on the “left” or at least tend to be inside the left’s political-communication bubble. Actually, people on the "right" think there is consensus against gun control; they live in their own bubble!

But there might be other explanations, too. . .

What do you think?


Finucane, Melissa L., Ali Alhakami, Paul Slovic, and Stephen M. Johnson. 2000. "The Affect Heuristic in Judgments of Risks and Benefits."  Journal of Behavioral Decision Making 13 (1):1-17.



Travel report: Has liberal democracy lost its power to motivate?

This is a belated postcard from stop on recent around the world (I know it was because it included both Cambridges—UK and US—with lots of stops in between) tour. . . . It reports on one of two talks I gave at the annual Breakthrough Institute Dialogue series.  This one was part of a panel on “Progress Problems,” in which the question that I and the other panelists, who included Max Roser and Lydia Powell, addressed was “why are so many of the richest and most privileged people on earth, despite reaping such extraordinary benefits,  convinced that progress is a mirage and modernity must inevitably end badly?My remarks, as best as I can recall them, were as follows (slides here) . . . .

So the question as I understand it is --

Have liberal democratic ideals lost the power to motivate the citizens of liberal democracies?

Can we summon their attention to the common challenges they face by invoking their shared commitment to self-government, civil liberties, and free markets? Or are the animating ideals of liberal democracy now themselves a source of estrangement and division that ennervate public spiritedness?

My answer to these qustions will take a dialectical form. That is, like Clint Eastwood at the Republican Convention of 2012, I will treat you to a disagreeable dialogue with myself, in which I will radically change direction at least twice.

But insofar as I will get the last word, I’m confident that I’ll ultimately come out on top in the exchange.

So to start, with . . .

                Thesis: Sure, those ideals can motivate! I’ll show you . . . .”

I’ll show you, that is, an experiment (Kahan, Jenkins-Smith et al. 2015), one in which invoking the spirit of liberal democratic institutions sharpened apprehension of, and magnified the will to address, a collective challenge –namely the one posed by human-caused global warming.

In the experiment, we measured the willingness of subjects (members of two separate nationally representatives samples, one from  American and the other from England) to engage open mindedly with a climate-change study.

A composite of two real studies (Allen et al. 2009; Solomon et al. 2009), the one featured in our experiment—call it the “Nature-Science study”—told a bleak story. Scientists, it reported, had overestimated the speed with which carbon dioxide dissipates. As a result, even if human beings were to cease generating all greenhouse gasses tomorrow, past emissions would guarantee continued increases in global temperatures along with devastating consequences—from catastrophic flooding of coastal regions, to production-ending droughts in agricultural ones—for decades to come.

We also measured our subjects cultural worldviews along the two dimensions—hierarchy-egalitarianism and individualism-communitarianism—featured in studies of the cultural cognition of risk (Kahan 2012).

As we anticipated, experiment subjects of a hierarchical, individualistic orientation—the ones most predisposed to climate skepticism—were preemptively dismissive of the Nature-Science study results.

This, however, was in a control condition, in which subjects, before grappling with the Nature-Science study, read a news article about a town meeting over a proposal to install traffic lights in the vicinity of a new residential development.

Subjects in two other conditions were assigned to read different news articles: in one, a story about how a national association of preeminent scientists had issued a statement calling for increased limits on human CO2 emissions to combat global warming; and in the other, a story about how the same association had issued a statement calling for research on geoengineering to offset the effects of past and future emissions. We labeled these the “anti-pollution” and “geoengineering” conditions.

Logically, there’s no reason why subjects assigned to either of these conditions should have formed different views on the validity of the Nature-Science study: the validity of the evidence for an asserted problem doesn’t turn on whether someone approves or disapproves of any particular solution for it.

But psychologically, the solution might well matter.

The “anti-pollution” and “geoengineering” stories embed the problem of climate change in different narratives and thus invest it with alternative social meanings (Lessig 1995).

The former narrative is about the inevitable limits on technological ingenuity and the consequences for having too long ignored them. Against the background of the “anti-pollution story,” the message of the Nature-Science story is  “game over” and “I told you so.”

Individuals of a hierarchical, individualistic cultural outlook revere commerce and industry, not just for what they do but for what they signify about human resourcefulness and the welfare-enhancing consequences of spontaneous private orderings and the stratified systems of authority that they spawn.  They are motivated, unconsciously, to resist evidence of the existence and impact of human-caused climate change precisely because they know that if society credits such evidence it will call into question the premises of their preferred way of life.

The social meanings in the anti-pollution story reinforce that perception, and hence amplify the motivation to resist the evidence.

But the message of the “geoengineering story” is very different.

We are not the stupid animal, this narrative goes, who when it reaches the top of the Malthusian curve comes crashing down ass over tincups.  We shift the f***ing curve!

Drinking your own shit, you say? No problem! Try modern sanitation & you can increase the density of cities 10 fold relative to what a bunch of tight-sphinctered naysayers once told us was the “natural limit,” enforced by the dreaded penalty of cholera outbreaks.

Well, it’s time to shift the curve again! This time with mirror-coated nanotechnology flying saucers that magically—hell, not magically; by rational intention & design—spontaneously assemble at just the right attitude to cool the atmosphere to a predetermined, geo-thermostatically determined level.

Not “game over” but more of the same!

“I told you so”? Unh uh! Try, yes we can!

Whereas the social meanings implicit in the “anti-pollution” story narrative threaten and denigrate the identity of the hierarch individualist, the meanings implicit in “geoengineering” affirm and gratify his vision of the best life and its prospects

The result is an abatement of the unconscious, reflexive resistance to evidence that there is in fact a problem to be addressed—by one means or another.

In any case, that was the conjecture we wanted to test in our experiment.

And it was the result that we in fact observed.

Relative to the control condition, hierarchical individualists in assigned to read the “anti-pollution” news story first became even more skeptical, even more dismissive of the validity of the Nature-Science study, increasing polarization within the study sample.

But those who read the “geoengineering” story first were decidedly more receptive to the evidence in the Nature-Science study; they didn’t dismiss its findings out of hand. 

As a result, polarization, over the validity of the study and over the reality of human-caused climate change, both decreased.

So there you go!

The ideals of liberal democracy include the  confidence that people have that technology, human ingenuity, private orderings, and individual strivings can in the course of freeing us from the limits of nature, devise effective solutions for problems of their own making.

Invoking these ideas, narratively, can inspire, can summon attention to common problems and the will to address them!

I’ve shown you!

 Antithesis: “No they can't! Take a closer look.”

Hold on.


What you’ve shown us is that liberal democratic ideals can’t genuinely motivate the citizens of liberal democratic regimes.  Just take a closer look at your own data, and you’ll see.

Yes, relative to their counterparts in the “antipollution” condition subjects in the “geoengineering” one became more open-minded about climate change.

But egalitarian communitarian subjects—people of the sort who normally are “climate concerned”—became less so.

They are the citizens who bridle at the self-centered acquisitiveness implicit in market institutions and in liberal conceptions of individual rights.

For them, the meanings of boundless individual ingenuity and permanent technological progress that pervade the narrative implicit in the “geoengineering” condition threatened and denigrate their identity.

If the meaning of climate change is “yes, we can” and “more of the same!,” then they want none of it.

Or least they want less.  Things aren’t that bad, egalitarian communitarian subjects assigned to the “geoengineering” condition said after reading the Nature-Science study.  We can still make “progress” by shutting down industry, turning off modern agricultural techniques, and simply retreating into a pre-modern style of economic life.

The scientists who wrote this study are biased, are relying on unproven computer models, are furnishing us with evidence that it would be precipitous to use in policymaking without a lot more corroboration etc etc.

Sound familiar? These are the tropes of skepticism—now from the mouths of those most inclined to be embrace climate change.

Why? Because what they really care about, what motivates them, is not  “evidence” (they definitely lack the science literacy to understand it) but the social meaning of “I told you!” and “game over!” (“This changes everything” blah blah) that informs the default narrative on climate change.

Change the narrative and they change their tune.

Just look at your data: They show that, relative to their counterparts in the anti-pollution condition, egalitarian communitarians became skeptical about climate change science in the in the geoengineering condition.

That, plus the greater receptivity to the Nature-Science study data on the part of hierarch individualists, was why there was less polarization in the “geoengineering” condition!

The motivation that invoking liberal democratic ideals, in the form of narratives of limitless technological progress and the self-corrective, self-redemptive power of private orderings and markets, is offset by the resistance that doing so motivates in that portion of or factionalized body politic that has come to despise individual striving, technology, and markets.

You can’t inspire with these ideals!

Invoking them on behalf of one cause of another is a zero sum game. 

Synthesis: “Liberal democratic ideals can indeed inspire--if you just stop obsessively looking at them.

I’m sorry.

You—both of you—are just playing a game.

What is this angst over the loss of the inspirational force of liberal democratic ideals, private markets included?  I mean really, what are you talking about?

Or better why are you focusing so much on talk—by such a small, small group of people who bother to theorize about these things?

Just look a tthe behavior of people—hierarch individualists, egalitarian communitarians, demoKrats/RepubliKans, “liberals,” “conservatives” or whatever.

Ambivalence about technology? Disaffection with consumption?

Ask Apple or Netflix or Amazon if that’s what their bottom lines tell them.

Yes your buddy’s new “environmental studies major” girlfriend is telling you about how environmentally destructive new information technologies are. But she’s showing you on her IPad, which has a “Green Party for Bernie Sander’s” IPad “skin”!

Against capitalism, Naomi Klein? Seriously? (Any chance you’ll show us your tax returns?)

Look.  This s a fashion statement:

And so is this:

Just as these opinions are:


Now here’s a worldview:

It’s real.

It’s anti-liberal.

It’s anti-market.

It’s anti-democratic.

And it’s just not on the table, in this society

No one around here finds this genuine repudiation of liberal democratic ideals the least bit inspiring.

The only thing that’s on the table here are the tokens of a demeaning, petty symbolic status competition driven by intellectually juvenile, self-promoting conflict entrepreneurs. . . . 

(Actually, you two guys both have garishly expensive but ridiculously dated sensibilities about fashion; in-your-face black is so 1999! You ain't no Johnny Cash, that's for sure.)

So don’t play that stupid game.

Stop looking & looking & looking at it.

“Messaging”/arguing liberal democracy doesn’t motivate people.

Living it does.


Allen, M.R., Frame, D.J., Huntingford, C., Jones, C.D., Lowe, J.A., Meinshausen, M. & Meinshausen, N. Warming caused by cumulative carbon emissions towards the trillionth tonne. Nature 458, 1163-1166 (2009).

Kahan, D.M., Hank, J.-S., Tarantola, T., Silva, C. & Braman, D. Geoengineering and Climate Change Polarization: Testing a Two-Channel Model of Science Communication. Annals of the American Academy of Political and Social Science 658, 192-222 (2015).

Lessig, L. The Regulation of Social Meaning. U. Chi. L. Rev. 62, 943-1045 (1995).

 Solomon, S., Plattner, G.-K., Knutti, R. & Friedlingstein, P. Irreversible climate change due to carbon dioxide emissions. Proceedings of the National Academy of Sciences 106, 1704-1709 (2009).




Weekend update: Scarier than Nanotechnology? Episode # 532


He or she not only emulates the facial expression of a real salamander but also "slithers [locomotes] just like the real thing"!

So is it cute or scary?

Will it disgust those who fear guns or those who fear drones?!

Only time will tell ... & only time will tell whether it grows/morphs into . . .



But for now, keep locomoting, little fellah!



The "Science Communication Problem": Two (of four) false starts

From On the Sources of Ordinary Science Knowledge--and Exraordinary Science Ignorance (in press):

2.2. A related false start blames scientists [for the Science Communication Problem--the failure of valid, compelling, widely disseminated science to disepel public disagreement over policy-relevant facts].

If members of the public aren’t converging on some policy-relevant facts despite the clarity of the evidence, the reason must be that scientists are failing to convey the evidence clearly enough (e.g., Brownell, Price & Steinman 2013). Or maybe they are speaking out too clearly, crossing the line from factfinder to policy advocate in a manner that compromises their credibility. Or perhaps what is compromising their credibility is how cagily they are hiding their advocacy by implausibly asserting that the  facts uniquely determine particular policy outcomes (e.g., Fischoff 2007).

While one can make a compelling normative case for either clearer (Olson 2009; Dean 2009) or less opinionated speech (Lempert, Groves & Fischbach 2013) by scientists, the idea that how scientists talk is the cause of the Science Communication Problem is palpably unconvincing. 

Again, all one has to do is look at science issues that don’t provoke persistent controversy. How about raw milk (Sci., Media, & Public Res. Group 2016)? Is there some reason to believe biologists have been doing a better job explaining pasteurization than climate scientists have been doing explaining the greenhouse effect? What folksy idioms or tropes did the former use that were so effective in quieting political polarization?  Or was it that they just were more genuinely neutral on whether people should drink their milk straight up from the cow’s udder?

Here, obviously, I’m relying on a pile of rhetorical questions in lieu of evidence. But the absence of evidence is my evidence.

No one has ever thought it worthwhile to “regress” the difference in public acceptance of, say, the scientific consensus on the dangers of ozone depletion and the scientific consensus on human-caused climate change on the clarity and policy-neutrality of the National Academy of Sciences’ respective reports on those issues (e.g, National Research Council 1976, 1982, 2008, 2011); or the difference between how rapidly and near-universally states adopted the proposed addition of the adolescent HBV vaccinationand how persistently they have resisted adoption of the HPV vaccine  (Kahan 2013) on the clarity and policy-neutrality of the American Academy of Pediatrics’ endorsements of both (American Academy of Pediatrics 1992, 2007).  

Likely no one has because it’s clear to the naked ear that what these groups of scientists had to say on the uncontested members of these societal-risk pairs was no less obscure and no less opinionated than what they had to say about the contested members of them. But whatever the source of the omission, the inclusion of only contested cases in the “sample” necessarily defeats any valid inference from the “obscurity” or “partisanship” of how scientists speak to why any particular policy-relevant fact is affected by the Science Communication Problem.

2.3.  Another false-start account of the Science Communication Problem attributes it to growing resistance to the authority of science itself. Along with widespread disbelief in evolution, political conflict over global warming or other issues is variously depicted as evidence of either the “anti-science” sensibilities of a particular segment of the public or of a creeping anti-science strain in American culture generally (e.g., Frank 2013). 

Anyone who manages to divert his gaze from the Science Communication Problem for even an instant is sure to spy evidence massively out of keeping with this account. In its biennial Science Indicators series, for example, the National Science Foundation  (2016) includes survey measures that consistently evince effusive degrees of confidence in and support for science (Figure 2). These levels of support do not vary meaningfully across groups defined by their political outlooks or degrees of religiosity (Figure 3). Indeed, the levels of support are so high that it would be impossible for them to harbor practically significant levels of variance across groups of any substantial size.

For behavioral validation of these sensibilities, all one has to do is look up from one’s desk (away from one’s monitor) to see the care-free confidence individuals evince in science when making decisions both mundane (the ingestion of a pill to preempt hair loss) and vital (submission to radiation therapy for cancer).


Because this evidence is so obvious, it’s less likely proponents of the “age of denial” thesis don’t see it than that they see it as irrelevant. On this view, confusion over or outright rejection of the admittedly authoritative evidence that science has collected on human-caused climate change or human evolution just is evidence of a deficit in the cultural authority of science.

Fine. But at that point what started out as an explanation for the Science Communication Problem has transmuted, ironically, into a piece of evidence-impervious dogma that rules out contrary proof  by definitional fiat. 


American Academy of Pediatrics, Committee on Infectious Diseases. Universal hepatitis B immunization. Pediatrics 8, 795-800 (1992).

American Academy of Pediatrics. HPV Vaccine Does Not Lead to Increased Sexual Activity (2012),

American Academy of Pediatrics. Prevention of Human Papillomavirus Infection: Provisional Recommendations for Immunization of Girls and Women With Quadrivalent Human Papillomavirus Vaccine. Pediatrics 120, 666-668 (2007).

Brownell, S.E., Price, J.V. & Steinman, L. Science communication to the general public: why we need to teach undergraduate and graduate students this skill as part of their formal scientific training. J. Undergraduate Neuroscience Educ. 12, E6 (2013).

Dean, C. Am I making myself clear? : a scientist's guide to talking to the public (Harvard University Press, Cambridge, Mass., 2009).

Fischhoff, B. Nonpersuasive Communication about Matters of Greatest Urgency: Climate Change. Environmental Science & Technology 41, 7204-7208 (2007).

Frank, A. Welcome to the age of denial. N.Y. Times (Aug. 21, 2013), available at

“Green Goo: Nanotechnology Comes Alive.” (Feb. 2003), at

Lempert, R.J., Groves, D.G. & Fischbach, J.R. Is it Ethical to Use a Single Probability Density Function? (Santa Monica, CA: RAND Corporation, 2013). Available at.

National Research Council (U.S.). Board on Atmospheric Sciences and Climate. & National Research Council (U.S.). Committee on Stabilization Targets for Atmospheric Greenhouse Gas Concentrations. Climate stabilization targets : emissions, concentrations, and impacts over decades to millennia (National Academies Press, Washington, D.C., 2011).

National Research Council (U.S.). Committee on Chemistry and Physics of Ozone Depletion. Causes and effects of stratospheric ozone reduction, an update : a report (National Academy Press, Washington, D.C., 1982).

National Research Council (U.S.). Committee on Ecological impacts of Climate Change. Ecological impacts of climate change (National Academies Press, Washington, D.C., 2008).

National Research Council (U.S.). Panel on Atmospheric Chemistry. Halocarbons, environmental effects of chlorofluoromethane release (National Academy of Sciences, Washington, 1976).

National Science Foundation. Science and Engineering Indicators 2016 (Wash. D.C., 2016).

Olson, R. Don't be such a scientist : talking substance in an age of style (Island Press, Washington, DC, 2009).

Science, Media, and the Public Research Group (SCIMEP).. Exploring Public Opinion and Risk Perceptions of Food in Wisconsin. University of Wisconsin-Madison. Madison, WI: Department of Life  Sciences Communication (2016). Available from

Vance, M.E., Kuiken, T., Vejerano, E.P., McGinnis, S.P., Hochella, M.F., Jr., Rejeski, D. & Hull, M.S. Nanotechnology in the real world: Redeveloping the nanomaterial consumer products inventory. Beilstei


Travel report: Is even the vote (not to mention all the voting) on Brexit irrational?...

So I was in Cambridge for the outstanding 7th Annual Risk Studies Summit  at Cambridge University's world-class Centre for Risk Studies this week (now am in San Fran for a couple).

Will write a separate report on that event.  But today on this Brexit business ...

Boy were folks in Cambridge depressed!

People there at least seem to be of one mind on the issue --

But what really seems to bug them is that the issue us up for a vote, and it looks like it will be close (we'll find out presently if so).  How can it be that so many people don't see things the way we do?, they are asking in consternation; what does that mean about the competence of our democratic electorate?

Sound familiar?

Well here's something familiar too:

The Online Privacy Foundation adapted the CCP Motivated Numeracy study to views on Brexit and in a study released yesterday observed the same perverse interactions between predispositions and reasoning proficiency.

I haven't had time to do more the casually peruse the results. But my sense is that there was in fact a finding of symmetry in the effect-- that is, that higher numeracy magnified biased information processing regardless of the subjects' Brexit predispositions.

That doesn't measn that the occasion of the vote isn't entangdeled in reason-effacing pathologies-- on the contary, reason is being effaced-- but it does mean (if I'm right aout the results; I reserve the right to reassess on closer examination & will tell you if I do change my view on this) that only one side is being affected by them.

They have some pretty nice graphis, too, I'll say that:

But that's all I have time for for now!  Others might want to chime in on what they think of the OPF study or generally about Brexit and rationality.

Of course, I'll be tuning in along w/ the 14 billion readers of this blog to get the reasults of the vote later today ...



Travel report: On unpolluted & polluted public health science communcation environments--the cases of the HBV & HPV vaccines (presentation summary & slides)

A rational reconstruction of the talk I gave—in 15' 22" [I can talk 9x faster than the average man, woman, or trained circus animal can read; and I pride myself on the 30-min sentence]—at the truly amazing “How we Can Improve Health Science Communication Conference” at U of Mich.’s amazing Center for Pol. Studies last week. Pretty sure the talks will be or perhaps already are on line.. . . Now am in UK for 7th Annual Cambridge Centre for Risks Studies Confernce – will write a postcard on that soon! Slides for  the U of M talk here.

1. As you know, my paper (in press) is on what I call the Science Communication Problem—the failure of valid, compelling, widely available scientific evidence to quiet public dispute over risks and like facts to which that evidence directly speaks.

The paper argues that our understanding of the Science Communication Problem is being distorted by fixation on conspicuous and specular instances of it—particularly  the conflict over climate change. 

Obviously,  empirical researchers should be focusing on how to decipher and ultimately dispel the Science Communication Problem. My claim, however, is that we won’t achieve these goals if we focus on instances of public dissensus to the near-total disregard of public consensus, which is far and away the norm on decision-relevant science.

 A research program that never diverts its gaze from climate change and other instances of the Science Communication Problem distracts our attention from evidence that would reveal the falsity of many popular accounts of why we have the Problem. It also steers us toward prescriptions that won’t repair the dynamics that ordinarily generate public convergence on the best available evidence and could even, perversely, inflict even more damage upon them.

I won’t rehearse my argument in detail, though. Instead I will try to illustrate it with a specific example not discussed in the paper: public conflict over the HPV vaccine.

2. As I’m sure y’all know, the HPV vaccine confers an imperfect but still important degree of immunity to the human papillomavirus, an extremely common sexually transmitted disease that causes cervical cancer. 

The HPV vaccine also has the distinction of being the only childhood shot recommended for universal administration by the CDC that is not now on the schedule of mandatory school-enrollment immunizations in US states.  Legislative proposals to add it were defeated in dozens of states in the years from 2007 to 2012 as a result of deep, pervasive political controversy over the safety and effectiveness of the vaccine (Kahan 2013).

It’s tempting to think this outcome was inevitable. The vaccine is for a sexually transmitted disease and was to be administered, initially, to pre-pubescent girls as a condition of their eligibility to attend public schools.  Of course, such a proposal would provoke controversy between groups that subscribe to opposing understandings of sexual morality, of parental sovereignty, and of role of the state in securing individual well-being.

But that conclusion—that the HPV-vaccine conflict was inevitable—reflects exactly the tunnel vision I’m attacking.

The HPV vaccine was not the first one that was aimed at a sexually transmitted disease recommended for universal administration to children. The HBV vaccine was.

The HBV vaccine confers immunity to hepatitis-b, which also causes cancer, of the liver.

The CDC proposed it be administered universally to adolescents (now to infants) just a few years before it proposed the  same for the HPV vaccine. With no significant controversy, the HBV vaccine was incorporated into the mandatory, school-enrollment immunization lists of nearly every U.S. state in a wave of approvals that crested just as the HPV-vaccine controversy began. At the time the HPV-vaccine controversy was raging, the HBV vaccine had an national uptake rate of over 90%--compared to the anemic 30% for the HPV Vaccine today (Kahan 2013).

Thus, the HPB vaccine,  is in the “denominator”—the vast class of decision-relevant science issues on which there isn’t public controversy but could be. What it shares with all the other members of that class is the benefit of having become known to the public in an unpolluted science communication environment

The science communication environment, I explain in the paper, consists of the sum total of processes and conventions generative of the cues that normally guide diverse individuals align their behavior with the best available evidence.

The HBV vaccine, like every universal childhood immunization before it, traveled safely through these processes and conventions to the destination of overwhelming public confidence. The vaccine was considered and approved for inclusion in state universal-immunization schedules by non-political public health agencies that have been delegated this expert task by state legislatures. The vast majority of parents thus had occasion to learn of the vaccine for the first time when their consent to administer it was sought from their pediatricians, individuals they had selected b/c they trusted them, who advised the vaccine was safe and a useful addition to the array of prophylactic practices that keep children healthy. Just as important, regardless of who they were—republican or democrat, devout evangelical or atheist or agonistic—all were afforded ample evidence that parents just like them were getting their kids vaccinated for HBV (Kahan 2013).

The decision to follow suit was a no brainer!

In contrast, parents and other citizens learned about the HPV vaccine in what I characterized as a polluted science communication environment.  A polluted science communication environment is one in which some risk or fact has become entangled in antagonistic social meanings that transform them into badges of membership in and loyalty to opposing cultural groups. In those conditions, the same cues that normally guide diverse citizens into convergence on the best available evidence—including what others in their situation are doing and saying-- instead drive them apart.

That’s what happened with the HPV vaccine. To try to establish a dominant position in the market before the approval of a competing HPV vaccine manufactured by its rival Smith-Glaxo Smithkline, Merck--manufacturer of the Gardasil, the HPV shot approved by the FDA in 2006--orchestrated a nationwide campaign to add the vaccine to the state, mandatory school-enrollment schedules by statutes enacted by state legislatures.

What was normally a nonpolitical decision—the updating the of state school-enrollment immunization lists—necessarily became hyper-politicized. People first learned of the vaccine not from their pediatricians but from Fox News, MSNBC, and other political news outlets, who hyped the repressive-in-your-face-religious right vs. the cosmopolitan, communism-of-women-and-children-left showdown on the “STD shot for school girls,” a framing facilitated by Merck’s decision to seek fast-track FDA approval of a girl’s only shot as part of its market-driven plan to sidestep the slower, less politicized approval process.

The result was the entanglement of the HPV vaccine in the sort of antagonistic meanings productive of the most debilitating of all known science-communication pathologies—identity-protective cognition (Kahan 2013).

3. Sarah Gollust and her collaborators (2010, 2013, 2014, 2015) have done a lot of outstanding work to identify and quantify the indicators of this entanglement and its disruptive impact on how ordinary members of the public ordinarily recognize valid science..

The CCP research group did a study on this too back in 2007, just as the process that resulted in this disaster began to unfold. In it we tried to model how different “science communication environments”—unpolluted and polluted—could affect engagement with information on the vaccine’s risks and benefits.

The study (Kahan, Braman, Cohen, Gastil & Slovic 2010) examined how cultural cognition could shape perceptions of the HPV vaccine. Cultural cognition refers to the tendency of people, in effect, to conform their  own perceptions of risk and like facts to the ones that predominate among others who share their cultural identities.

We measured individuals cultural identities with two orthogonal attitudinal scales, hierarchy-egalitarianism and individualism-communitarianism, which can be viewed as forming four types of cultural “affinity groups.”

Next, we exposed them to competing arguments on the balance of risks and benefits of the HPV vaccine from  fictional “public health experts.” The experts were ones we had determined in separate pretests would be tacitly identified by the experimental subjects as having the cultural identifies featured by the cultural cognition worldview scheme.

By crossing the two arguments with the four advocates, we had had 12 HPV “expert-argument matchups.” To assess their impact, we modeled how the proximity of the subjects’ actual cultural outlooks to the experts' tacitly perceived ones affected subjects’ HPV-vaccine risk perceptions.

Our goal  in simultaneously manipulating the array of experts and arguments, on the one hand, and the proximity of the experts' cultural outlooks to the subjects', on th the other, was to simulate the impact of learning about the vaccine under conditions that would themselves vary in how readily they suggested the presence or absence of division of opinion between subjects’ own cultural groups and a rival one.

The simulation suggested that the impact was yuuuuuuuugely consequential.

In effect, there was a continuous polarization effect that tracked subjects' tacit impressions of group conflict.  

We knew, again  from pretesting, that subjects with particular identities had modest predispositions to form one or another impression of the safety and efficacy of the vaccine.

But under the condition least likely to suggest group conflict—the one in which subjects saw an alignment of culturally identifiable experts and arguments contrary to the one they would have expected to see if the issue were in fact dividing groups consistent with subjects’ own predispositions—polarization essentially disappeared.

Where in contrast they saw the alignment most suggestive of such conflict—the one in which an expert with their identity took “their side’s” position and one with opposing identity “the other side’s”—polarization dramatically escalated relative to the level predicted by the subjects’ predispositions alone.

These two points on the continua reflect a pristine and a polluted science communication environment, respectively. The first was the environment in which American parents learned of the HBV vaccine; the latter the one in which they learned of the proposal to add the HPV vaccine to the schedule of mandatory school-enrollment immunizations.

4. Likely this condition could have been avoided. Lots of physicians and others were worried that the manner in which the HPV vaccine was being introduced to the public risked generating a political controversy (Kahan 2013).

But the question now is whether anyone is going to learn from this experience and from research on it, including our study and the penetrating set by Gollust and her collaborators.

The answer, I think, will depend largely on whether members of the public health establishment avoid the mistake of “ignoring the denominator”—the relatively large number of cases in which the public doesn’t polarize but rather converge on the best available scientific evidence. Frankly, I think many of the proposals on how to over come the continuing public ambivalence on the HPV vaccine reflect exactly that mistake.

One prominent proposal is to conduct a large-scale social marketing campaign promoting the vaccine. Thrusting the HPV vaccine back into the limelight in this way would risk exciting the very sorts of sensibilities—and more importantly reigniting the same sort of interest group activity —that bred the initial conflict. Indeed, this idea sounds more or less like a proposal to take out of mothballs the very advertisements that Merck bankrolled during its disastrous campaign to secure legislative mandates.

Just look at the denominator!

There wasn’t any social marketing campaign on HBV vaccine, just as there wasn’t any on the myriad other science issues—from medical x-rays to nanotechnology—on which diverse members of the public now have aligned their behavior appropriately by science.

The mechanism, moreover, in those cases hasn't been the public's reflective processing of detailed bits of medical or other scientific information. It has been their attention to the cue emitted by the words and behavior of others who have evinced their confidence  by words and deeds showing that they have confidence in the underlying science.

An unpolluted science communication environment is not bustiling with broadcast messages. On the contrary, it comprises a host of persitent low key signals that assure that people that doing things that rely on what is in fact the best available evidence is mundane, banal normal.

The question is how to promote this sort of normality to people's engagement with the HPV vaccine.

I’ll give you a hint on the answer.

The one state, Rhode Island, that has adopted an HPV-vaccine school-enrollment mandate in the years since the initial political firestorm over this proposal abated did so without particular fanfare—by resort to the nonpolitical administrative process that is  actually the norm for updating state mandatory vaccination regimes. 

Parents in RI aren't now learning about the HPV vaccine from media reports on a contested legislative mandate for an STD shot for their pre-teen children; they didn’t learn about it from a weird and very likely counterproductive (Nyhan et al. 2014) social marketing campaign. 

Rather they are getting the information in the normal way—from talking to their pediatricians about it at the same time they discuss other immunizations that their children are required to get, and from seeing that other parents just like them, after having done the same, are making decisions to get their kids vaccinated for HPV—just as they are making the decision (at rates well over 90%) to do the same for HBV, MMR and all the other childhood diseases from which their kids and lots of others too are protected by universal immunizations.

It's a no brainer!

It's no big deal.


Gollust, S.E. & Cappella, J.N. Understanding public resistance to messages about health disparities. Journal of health communication 19, 493-510 (2014).

Gollust, S.E., Attanasio, L., Dempsey, A., Benson, A.M. & Fowler, E.F. Political and News Media Factors Shaping Public Awareness of the HPV Vaccine. Women's Health Issues 23, e143-e151 (2013).

Gollust, S.E., Dempsey, A.F., Lantz, P.M., Ubel, P.A. & Fowler, E.F. Controversy undermines support for state mandates on the human papillomavirus vaccine. Health Affair 29, 2041-2046 (2010).

Gollust, S.E., LoRusso, S.M., Nagler, R.H. & Fowler, E.F. Understanding the role of the news media in HPV vaccine uptake in the United States: Synthesis and commentary. Human vaccines & immunotherapeutics, 1-5 (2015).

Kahan, D., Braman, D., Cohen, G., Gastil, J. & Slovic, P. Who Fears the HPV Vaccine, Who Doesn’t, and Why? An Experimental Study of the Mechanisms of Cultural Cognition. Law Human Behav 34, 501-516 (2010).

Kahan, D.M. A Risky Science Communication Environment for Vaccines. Science 342, 53-54 (2013).

Kahan, D.M. On the sources of ordinary science intelligence and ignorance. Oxford Handbook on the Science of Science Communicatoin (in press).

Nyhan, B., Reifler, J., Richey, S. & Freed, G.L. Effective messages in vaccine promotion: A Randomized Trial. Pediatrics 133, e835-e842 (2014).


The fourth of "four theses on ordinary science intelligence" ... a fragment

I posted the first two "yesterday"; if you want to read the third, then just download   On the Sources of Ordinary Science Knowledge and Ignorance . . .

IV. “The recognition problem [that generates conflict over decision relevant science] is a polluted science communication environment.”

The species of pattern recognition that ordinary members of the public normally use to recognize valid science enables them to get the benefit of substantially more scientific insight than any could possibly hope to genuinely comprehend.  The evidence I described in the last section, however, evinces the disablement of this critical capacity.  The final “thesis of ordinary science knowledge” identifies the source of this disablement: a polluted science communication environment.

Popper (1962b), I noted, attributes the acquisition and exercise of the capacity for science-recognition to immersion in a set of social processes and conventions. When I refer to the science communication environment, I mean to refer to the sum total of the processes and conventions that enable recognition of valid science in this way (Kahan 2015b). Any influence that impairs or impedes the operation of these social practices will necessarily degrade the power of free, reasoning citizens to recognize valid science, and hence to realize the full benefits of it. As a result, we may understand any such influence to be a form of pollution in the science communication environment.

The sorts of influences that can generate such disablement are no doubt numerous and diverse. But I will focus on one, which degrades an especially consequential cue of science validity.

Of all the sources of ordinary science knowledge, by far the most significant will be individuals’ interactions with others with whom they a share cultural commitments or basic understanding of the best way to live. The suggestion that direct communication with scientists is more consequential reflects either the First or Second False Start or both: individuals have neither the time nor the capacity to extract information directly from scientists.  Much more accessible, and much more readily subject to meaningful interpretation, are words and actions of other ordinary people, whose use of DRS vouches for their confidence in it as a basis for decision. 

Indeed, it vouches as effectively when nothing is said about it as it does when something is. Nothing—including a new National Academy of Sciences expert consensus report (National Research Council 2016) that few members of the public will even be dimly aware exists—will assure an ordinary person that it is safe to eat GM corn chips as will watching his best friend and his brother-in-law and his officemate eating them without giving the matter a second’s thought, the “all clear” signal that obviates the need for the vast majority of Americans even to bother learning that the corn chips they are eating contain GM foods (Hallman, Cuite & Morin 2013).

Of course, ordinary citizens don’t interact only with those with whom they share important cultural commitments. But they interact with them much more than they interact with others, for the simple reason that they find their company more congenial and more productive of all manner of profitable intercourse. They are also less likely to was time squabbling with these people, and can also read them more reliably, distinguishing who really does know what science knows and who is only a poser. It is perfectly rational for them consciously to seek out guidance from such individuals, then, or to form unconscious habits of mind that privilege them as sources of guidance on what science knows (Kahan 2015b).

Figure 5 ... click on it: it will increase your proportion of fast-twitch to slow-twich mucle fibers by 23.6%!This process is admittedly insular, but it clearly works in the main. All of the major cultural groups in which this process operate are amply stocked both with members high in science comprehension and with intact social processes for transmitting what they know. No group that lacked these qualities—and that as a result regularly misled its members on the content of valid DRS—would last very long! On issues that don’t display the profile of the Science Communication Paradox, moreover, individuals highest in science proficiency do tend to converge on the best available evidence, and no doubt pull the other members of their groups along in their wake (Figure 5).

But such a system is vulnerable to a distinctive pathology: identity-protective cognition (IPC). IPC occurs when a policy-relevant fact that admits of empirical inquiry becomes entangled in antagonistic social meanings that transform positions on them into badges of identity in, and loyalty to, competing cultural groups (Kahan 2010, 2012). The cost under those conditions of forming factually incorrect beliefs on matters like whether humans are heating up the earth or whether fracking will extinguish or contaminate drinking water sources is essentially zero: individuals’ personal views and actions are not consequential enough to affect the level of risk they face, or the likely adoption of ameliorating (or simply pointless or even perverse) regulatory responses. But given what beliefs on these subjects (correct or incorrect) have come to signify about the kind of person one is—about whose side on is on, in what has become a struggle for status among competing cultural groups—the personal cost of forming the wrong ones in relation to one’s own cultural identity could be high indeed (Kahan, Peters et al. 2012).

In such circumstances, individuals can be expected to use their reason to form and persist in beliefs that reliably vouch for their group identities regardless of whether those beliefs are factually accurate.  This conclusion is consistent with numerous studies, observational (Bolsen & Druckman 2015; Bolsen, Druckman & Cook 2014; Gollust, LaRussao et al. 2015; Gollust, Dempsey, et al. 2010) and experimental (Kahan, Braman, et al. 2009, 2010), that link IPC to the Science Communication Problem’s signature forms of polarization.  Indeed, individuals who enjoy the highest level of proficiency will display this form of motivated reasoning to the greatest extent, precisely because they will be the most adept at using their reasoning proficiency secure the interest that they share to form identity-expressive beliefs (Kahan in press).

In sum, the antagonistic social meanings that trigger IPC are a toxic form of pollution in the science communication environment of culturally pluralistic societies.  They disable individuals’ science-recognition capacities, not by degrading their reason but by conscripting it into the service of advancing their group’s cause in a demeaning form of cultural status competition. IPC does not create the role that social influences play in popular recognition of what science knows. Rather it corrupts them, transforming the role that  spontaneous, everyday social interactions play from an engine of convergence on the beset available evidence into a relentlessly aggressive agent of public dissensus over what scientific consensus really is. 


Bolsen, T. & Druckman, J.N. Counteracting the Politicization of Science. Journal of Communication 65, 745-769 (2015).

Bolsen, T., Druckman, J.N. & Cook, F.L. The influence of partisan motivated reasoning on public opinion. Polit Behav 36, 235-262 (2014).

Gollust, S.E., Dempsey, A.F., Lantz, P.M., Ubel, P.A. & Fowler, E.F. Controversy undermines support for state mandates on the human papillomavirus vaccine. Health Affair 29, 2041-2046 (2010).

Gollust, S.E., LoRusso, S.M., Nagler, R.H. & Fowler, E.F. Understanding the role of the news media in HPV vaccine uptake in the United States: Synthesis and commentary. Human vaccines & immunotherapeutics, 1-5 (2015).

Hallman, W., Cuite, C. & Morin, X. Public Perceptions of Labeling Genetically Modified Foods. Rutgers School of Environ. Sci. Working Paper 2013-2001, available at

Kahan, D. Fixing the Communications Failure. Nature 463, 296-297 (2010).

Kahan, D. Why we are poles apart on climate change. Nature 488, 255 (2012).

Kahan, D.M., Peters, E., Wittlin, M., Slovic, P., Ouellette, L.L., Braman, D. & Mandel, G. The polarizing impact of science literacy and numeracy on perceived climate change risks. Nature Climate Change 2, 732-735 (2012).

National Research Council (U.S.). Committee on Genetically Engineered Crops. Genetically Engineered Crops: Experiences and Prospects  (National Academies Press, Washington, D.C., 2016).

Popper, K.R. On the Sources of Knowledge and of Ignorance. in Conjectures and Refutations 3-40 (Oxford University Press London, 1962b).



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