Dan M. Kahan Yale University & many others Thinking Scientifically About Climate Science Communication

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem

“How much risk do you believe climate change poses to human health, safety, or prosperity?” source: 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 Clim. Change, 2, (2012). Greater Lesser perceived risk (z-score) U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence.

Greater Lesser perceived risk (z-score) PIT prediction: Science Illiteracy & Bounded Rationality High Sci. litearcy/System 2 (“slow”) Low Sci. litearcy/System 1 (“fast”) “How much risk do you believe climate change poses to human health, safety, or prosperity?” source: 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 Clim. Change, 2, (2012). U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence.

Lesser Risk Greater Risk Science literacy Numeracy low high perceived risk (z-score) lowhigh PIT prediction actual variance “How much risk do you believe climate change poses to human health, safety, or prosperity?” source: 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 Clim. Change, 2, (2012). U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence.

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning

Hierarchy Egalitarianism Cultural Cognition Worldviews Individualism Communitarianism hierarchical individualists hierarchical communitarians egalitarian communitariansegalitarian individualists Risk Perception Key Low Risk High Risk

Hierarchy Egalitarianism Abortion procedure Individualism Communitarianism Environment: climate, nuclear Guns/Gun Control HPV Vaccination Gays military/gay parenting Environment: climate, nuclear hierarchical communitarians egalitarian individualists Cultural Cognition Worldviews egalitarian communitarians Risk Perception Key Low Risk High Risk cats/annoying varmints

Source: Kahan, D.M., Jenkins-Smith, H. & Braman, D. Cultural Cognition of Scientific Consensus. J. Risk Res. 14, (2011).

Hierarchy Egalitarianism Cultural Cognition Worldviews Risk Perception Key Low Risk High Risk Individualism Communitarianism Climate change Nuclear waste disposal Concealed carry bans

Source: Kahan, D.M., Jenkins-Smith, H. & Braman, D. Cultural Cognition of Scientific Consensus. J. Risk Res. 14, (2011).

High Risk (science conclusive) Low Risk (science inconclusive) Climate Change

Low Risk (safe) High Risk (not safe) Geologic Isolation of Nuclear Wastes

High Risk (Increase crime) Low Risk (Decrease Crime) Concealed Carry Laws

N = 1,500. Derived from ordered-logit regression analysis, controlling for demographic and political affiliation/ideology variables. Culture variables set 1 SD from mean on culture scales. CIs reflect 0.95 level of confidence Concealed Carry Climate Change Nuclear Power 31% 54% 22% 58% 61% 72% Pct. Point Difference in Likelihood of Selecting Response 60% 40% 20% 0 20% 40% 60% Egalitarian Communitarian More Likely to Agree Hierarchical Individualist More Likely to Agree Featured scientist is a knowledgeable and credible expert on...

Hierarchy Egalitarianism Cultural Cognition Worldviews Risk Perception Key Low Risk High Risk Individualism Communitarianism Climate change Nuclear waste disposal Concealed carry bans

Hierarchy Egalitarianism Cultural Cognition Worldviews Individualism Communitarianism Climate change Nuclear waste disposal Perceived Scientific Consensus: Low Risk High Risk Concealed carry bans

Greater Lesser perceived risk (z-score) “How much risk do you believe climate change poses to human health, safety, or prosperity?” Low Sci lit/numeracy High Sci lit/numeracy Cultural Variance Hierarchical Individualist Egalitarian Communitarian U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence. source: 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 Clim. Change, advance online publication (2012), doi: /nclimate1547. Cultural variance conditional on sci. literacy/numeracy?

Greater Lesser perceived risk (z-score) “How much risk do you believe climate change poses to human health, safety, or prosperity?” Low Sci lit/numeracy High Sci lit/numeracy Egalitarian Communitarian PIT prediction: Culture as heuristic substitute Hierarchical Individualist U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence. source: 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 Clim. Change, advance online publication (2012), doi: /nclimate1547.

Greater Lesser perceived risk (z-score) “How much risk do you believe climate change poses to human health, safety, or prosperity?” High Sci lit/numeracy Actual interaction of culture & sci-lit/num... Low Sci lit/numeracy High Sci lit/numeracy Egal Comm Low Sci/lit numeracy Egal Comm Low Sci lit/num. Hierarc Individ High Sci lit/numeracy Hierarch Individ U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence. source: 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 Clim. Change, advance online publication (2012), doi: /nclimate1547.

Greater Lesser perceived risk (z-score) “How much risk do you believe climate change poses to human health, safety, or prosperity?” High Sci lit/numeracy Low Sci lit/numeracy Low Sci lit/num. Hierarc Individ High Sci lit/numeracy Egal Comm High Sci lit/numeracy Hierarch Individ Low Sci/lit numeracy Egal Comm Actual interaction of culture & sci-lit/num... U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence. source: 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 Clim. Change, advance online publication (2012), doi: /nclimate1547.

Greater Lesser perceived risk (z-score) “How much risk do you believe climate change poses to human health, safety, or prosperity?” High Sci lit/numeracy Low Sci lit/numeracy Low Sci lit/num. Hierarc Individ POLARIZATION INCREASES as scil-lit/numeracy increases High Sci lit/numeracy Egal Comm High Sci lit/numeracy Hierarch Individ Low Sci/lit numeracy Egal Comm U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence. source: 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 Clim. Change, advance online publication (2012), doi: /nclimate1547.

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

“Skin cream experiment”

“Gun ban experiment”

Four conditions

Numeracy Conserv_Repub is standardized sum of standardized responses to 5-point liberal- conservative ideology and 7-point party-self-identification measures.

Correct interpretation of data rash decreases rash increases Numeracy score Lowess smoother superimposed on raw data.

numeracy score at & above which subjects can be expected to correctly interpret data. Numeracy

Correct interpretation of data

skin treatment Gun ban

Correct interpretation of data Liberal Democrats (< 0 on Conservrepub) Conserv Republicans (> 0 on Conservrepub) skin treatment Gun ban

N = Outcome variable is “Correct” (0 = incorrect interpretation of data, 1 = correct interpretation). Predictor estimates are logit coefficients with z-test statistic indicated parenthetically. Experimental assignment predictors— rash_decrease, rash_increase, and crime_increase—are dummy variables (0 = unassigned, 1 = assigned—with assignment to “crime decreases” as the comparison condition. Z_numeracy and Conserv_Repub are centered at 0 for ease of interpretation. Bolded typeface indicates predictor coefficient is significant at p < Best fitting regression model for experiment results rash_decrease0.40(1.57) rash increase0.06(0.22) crime increase1.07(4.02) z_numeracy-0.01(-0.05) z_numeracy_x_rash_decrease0.55(2.29) z_numeracy_x_rash_increase0.23(1.05) z_numeracy_x_crime_increase0.46(2.01) z_numeracy20.31(2.46) z_numeracy2_x_rash_decrease0.02(0.14) z_numeracy2_x_rash_increase-0.07(-0.39) z_numeracy2_x_crime_increase-0.31(-1.75) Conserv_Repub-0.64(-3.95) Conserv_Repub_x_rash_decrease0.56(2.64) Conserv_Repub_x_rash_increase1.28(6.02) Conserv_Repub_x_crime_increase0.63(2.82) z_numeracy_x_Conserv_repub-0.33(-1.89) z_nuneracy_x_Conserv_Repub_x_rash_decrease0.33(1.40) z_nuneracy_x__x_rash_increase0.54(2.17) z_nuneracy_x__x_crime_increase0.26(1.08) _constant-0.96(-4.70)

High numeracyLow numeracy high numeracy = 8 correct low numeracy = 3 correct Regression model predicted probabilities skin treatment Gun ban probabilility of correct interpretation of data rash decreases rash increases rash decreases rash increases rash decreases rash increases rash decreases rash increases crime increases crime decreases crime increases crime decreases crime increases crime decreases crime increases Liberal Democrat (-1 SD on Conservrepub) Conserv Republican (+1 SD on Conservrepub) 0%10%20% 30% 40% 50%60%70% 80%90%100% 0%10%20% 30% 40% 50%60%70% 80%90%100% 0%10%20% 30% 40% 50%60%70% 80%90%100% 0%10%20% 30% 40% 50%60%70% 80%90%100% crime decreases

Numeracy magnification of motivated reasoning Avg. “polarization” on crime data for high numeracy partisans 46% (± 17%) Avg. “polarization” on crime data for low numeracy partisans 25% (± 9%) High numeracyLow numeracy

High numeracyLow numeracy EC rash increases HI crime decrease HI crime increase EC crime decrease EC crime increase HI crime decrease HI crime increase EC crime decrease EC crime increase HI rash increases HI rash decreases probabilility of correct interpretation of data EC rash decreases EC rash increases HI rash increases HI rash decreases skin treatment Gun ban high numeracy = 8 correct low numeracy = 3 correct Egalitarian communitarian (-1 SD on Hfac & Ifac) Hierarch individid (+1 SD on Hfac & Ifac)

Greater Lesser perceived risk (z-score) “How much risk do you believe climate change poses to human health, safety, or prosperity?” High Sci lit/numeracy Low Sci lit/numeracy Low Sci lit/num. Hierarc Individ POLARIZATION INCREASES as scil-lit/numeracy increases High Sci lit/numeracy Egal Comm High Sci lit/numeracy Hierarch Individ Low Sci/lit numeracy Egal Comm U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence. source: 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 Clim. Change, advance online publication (2012), doi: /nclimate1547.

Not too little rationality, but too much. The science communication problem

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: * to the ordinary decisionmaker:

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: * to the ordinary decisionmaker:

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: * to the ordinary decisionmaker: normal climate science

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: * to the ordinary decisionmaker: normal climate science

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: the normality/ * to the ordinary decisionmaker: normal climate science

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: the normality/banality * to the ordinary decisionmaker: normal climate science

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: the normality/banality of climate science * to the ordinary decisionmaker: normal climate science

The science communication problem Not too little rationality, but too much.

Hierarchy Egalitarianism Individualism Communitarianism hierarchical individualists hierarchical communitarians egalitarian communitariansegalitarian individualists Cultural Cognition Worldviews

Hierarchy Egalitarianism Communitarianism Individualism

Correct interpretation of data Liberal Democrats (< 0 on Conservrepub) Conserv Republicans (> 0 on Conservrepub)

Correct interpretation of data Liberal Democrats (< 0 on Conservrepub) Conserv Republicans (> 0 on Conservrepub)

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: the normality/banality of climate science * to the ordinary decisionmaker: normal climate science

very high risk No risk at all Science literacy score Egalitarian Communitarian Hierarchical Individualist How much risk do you believe global warming poses to human health, safety, or prosperity?) 4 counties: science literacy, culture & climate change risk perceptions N = 2,000. Fitted regression values

“normality/banality”

“Abnormal—but exciting!”

Egalitarian CommunitarianHierarchical Individualist How do you feel about the Southeast Florida Regional Climate Compact (the 4-county governmental association addressing sea-level rise issues?) Normal/banal Abnormal

Normal/banal How do you feel about the Southeast Florida Regional Climate Compact (the 4-county governmental association addressing sea-level rise issues?) Egalitarian CommunitarianHierarchical Individualist Abnormal

Normal/banal Abnormal How do you feel about the Southeast Florida Regional Climate Compact (the 4-county governmental association addressing sea-level rise issues?) Egalitarian CommunitarianHierarchical Individualist

How much risk do you believe global warming poses to human health, safety, or prosperity?) very high risk No risk at all Egalitarian Communitarian Hierarchical Individualist very high risk No risk at all

Greater Lesser perceived risk (z-score) “How much risk do you believe climate change poses to human health, safety, or prosperity?” High Sci lit/numeracy Low Sci lit/numeracy Low Sci lit/num. Hierarc Individ POLARIZATION INCREASES as scil-lit/numeracy increases High Sci lit/numeracy Egal Comm High Sci lit/numeracy Hierarch Individ Low Sci/lit numeracy Egal Comm U.S. general population survey, N = 1,500. Scale 0 (“no risk at all”) to 10 (“extreme risk”), M = 5.7, SD = 3.4. CIs reflect 0.95 level of confidence. source: 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 Clim. Change, advance online publication (2012), doi: /nclimate1547.

very high risk No risk at all Science literacy score Egalitarian Communitarian Hierarchical Individualist How much risk do you believe global warming poses to human health, safety, or prosperity?) 4 counties: science literacy, culture & climate change risk perceptions N = 2,000. Fitted regression values

Communicating Normality

1. A plausible but incorrect explanation: the public irrationality thesis (PIT) 2. Another, better one 3. Communicating what to whom about climate science The science communication problem : motivated reasoning * to the ordinary citizen: the normality/banality of climate science * to the ordinary decisionmaker: normal climate science

Cultural Cognition Cat Scan Experiment Go to