1. Motivated System 2 Reasoning and Science Curiosity:
Motivated System 2 Reasoning and Science Curiosity:
Two Individual Differences in Politically Motivated Reasoning
Dan M. Kahan
Yale University
& many x 103 others

3. Behavioural Public Policy, in press
Advances in Pol. Psych. ,

4. “Skin cream experiment”

5. “Skin cream experiment”

6. Two conditions

7. Correct interpretation of data
rash decreases
rash increases
incorrect
Numeracy score
Lowess regression line.

8. Covariance & Numeracy
Bars denote 0.95 CIs.

9. “Gun ban experiment”

10. “Gun ban experiment”

11. Four conditions

12. Correct interpretation of data
skin treatment
Numeracy score
Gun ban
Lowess regression line.

13. Correct interpretation of data
skin treatment
Numeracy score
Gun ban
Numeracy score
Lowess regression line.

14. Lowess regression line.

15. Regression model for experiment results
rash_decrease
0.40
(1.57)
rash increase
0.06
(0.22)
crime increase
1.07
(4.02)
z_numeracy
-0.01
(-0.05)
z_numeracy_x_rash_decrease
0.55
(2.29)
z_numeracy_x_rash_increase
0.23
(1.05)
z_numeracy_x_crime_increase
0.46
(2.01)
z_numeracy2
0.31
(2.46)
z_numeracy2_x_rash_decrease
0.02
(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_decrease
0.56
(2.64)
Conserv_Repub_x_rash_increase
1.28
(6.02)
Conserv_Repub_x_crime_increase
0.63
(2.82)
z_numeracy_x_Conserv_repub
-0.33
(-1.89)
z_nuneracy_x_Conserv_Repub_x_rash_decrease
0.33
(1.40)
z_nuneracy_x__x_rash_increase
0.54
(2.17)
z_nuneracy_x__x_crime_increase
0.26
(1.08)
_constant
-0.96
(-4.70)
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 < 0.05.

16. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
skin treatment
rash increases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
Gun ban
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

17. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
25%, ± 10
skin treatment
rash increases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
Gun ban
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

18. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
skin treatment
rash increases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime increases
crime increases
crime decreases
crime decreases
Gun ban
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

19. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
skin treatment
rash increases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime increases
crime increases
crime decreases
crime decreases
Gun ban
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

20. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
5%, ± 6
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decrease
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime increases
crime increases
crime decreases
crime decreases
Gun ban
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

21. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decreases
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime increases
crime increases
crime decreases
crime decreases
Gun ban
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

22. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decreases
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime increases
crime increases
crime decreases
crime decreases
Gun ban
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

23. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decreases
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime decreases
crime increases
crime increases
crime decreases
crime decreases
crime decreases
Gun ban
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

24. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decreases
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime increases
crime increases
crime increases
crime decreases
crime decreases
Gun ban
crime increases
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

25. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decreases
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime decreases
crime increases
crime increases
crime increases
crime decreases
crime decreases
crime decreases
Gun ban
crime increases
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

26. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decreases
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime decreases
crime increases
crime increases
crime increases
crime decreases
crime decreases
crime decreases
crime decreases
Gun ban
crime increases
crime increases
crime decreases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

27. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decreases
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime decreases
crime increases
crime increases
crime increases
crime increases
crime increases
crime decreases
crime decreases
crime decreases
Gun ban
crime increases
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

28. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
rash increases
rash increases
rash decreases
rash decreases
rash decreases
rash decreases
rash decreases
rash increases
rash increases
skin treatment 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
crime increases
80%
90%
100%
crime decreases
crime decreases
crime increases
crime increases
crime increases
crime increases
crime increases
crime decreases
crime decreases
crime decreases
crime decreases
crime decreases
Gun ban
crime increases
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

29. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
Avg. “polarization”
on crime data
for low numeracy
partisans
25% (± 9%)
Avg. “polarization”
on crime data
for high numeracy
partisans
46% (± 17%)
crime decreases
crime decreases
crime increases
crime increases
crime increases
crime increases
crime increases
crime decreases
crime decreases
crime decreases
crime decreases
crime decreases
Gun ban
crime increases
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

30. Bounded rationality thesis

31. Conservative Republican
BRT prediction
Reality
Liberal Democrat
Conservative Republican

32. Conservative Republican
BRT prediction
Reality
Liberal Democrat
Conservative Republican

33. Conservative Republican
BRT prediction
Reality
Liberal Democrat
Conservative Republican

34. Conservative Republican
BRT prediction
Reality
Conservative Republican
Adapted from 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, (2012).

35. Conservative Republican
There is “solid evidence” of recent global warming due “mostly” to “human activity such as burning fossil fuels.” [agree, disagree]
Liberal Democrat
Probability of “agree”
Conservative Republican
Ordinary Science Intelligence (percentile)
N = shaded areas denote 0.95 CIs.

36. Conservative Republican
There is “solid evidence” of recent global warming due “mostly” to “human activity such as burning fossil fuels.” [agree, disagree]
Liberal Democrat
Probability of “agree”
Conservative Republican
Actively Open-minded Thinking (zscore)
N= 750. Derived from logistic regression. Colored barsdenote 0.95 CIs.

37. Conservative Republican
There is “solid evidence” of recent global warming due “mostly” to “human activity such as burning fossil fuels.” [agree, disagree]
Liberal Democrat
Probability of “agree”
Conservative Republican
Cognitive Reflection Test (no. correct)
N = Brackets denote 0.95 CIs.

38. N = 1759. Shaded area denote 0.95 CIs.

39. N = 1759. Shaded area denote 0.95 CIs.

40. N = 1759. Shaded area denote 0.95 CIs.

41. N = 1759. Shaded area denote 0.95 CIs.

42. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
Avg. “polarization”
on crime data
for low numeracy
partisans
25% (± 9%)
Avg. “polarization”
on crime data
for high numeracy
partisans
46% (± 17%)
crime decreases
crime decreases
crime increases
crime increases
crime increases
crime increases
crime increases
crime decreases
crime decreases
crime decreases
crime decreases
crime decreases
Gun ban
crime increases
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

43. Bounded rationality thesis

44. Advances in Pol. Psych. ,

46. State of the art “Science Curiosity”/“curiosity”
Test of Science Related Attitudes (TOSRA)
I am curious about the world in which we live
I find it boring to hear about new ideas
I would enjoy visiting a science museum at the weekend
I would like to be given a science book as a present
I get bored when watching science programs on TV

47. Sample self-report item

48. Sample self-report item

49. Sample (self-report) behavior

50. Sample (self-report) behavior

51. Performance measure

52. “Science Curiosity Scale” (SCS_1.0 ) A little but not closely
(item response theory 2PL) .1 .2 .3 .4 .5 .6 .7 .8 .9 1
probability of pro-curiosity response -3 -2 -1 2 3
science curiosity
read book on “scientific research or discoveries” in last yr
Read science book in last yr
BSCIENCE
how closely follow news on “scientific research or discoveries”
Not at all
very closely
A little but not closely
closely
Science Curiosity Index (SCI)
Science Curiosity Index (SCI)

53. YIF Clip: Origins of color vision

55. Evolution disbeliever Evolution disbeliever
Request full show: Evolution “believers” vs. “disbelievers”
Evolution believer
Evolution believer
probability of requesting full show
Evolution disbeliever
Evolution disbeliever
Science Curiosity (percentie)
Science Curiosity
Logistic regression. Colored bars reflect 0.95 level of confidence

56. Was the information “believable”?

58. Study 2 goals & results: Replication & robustness of SCS
Mass Extinction: Life at the Brink
Darwin’s Dangerous Idea

59. Study 2 goals & results:
Replication & robustness of SCS

60. Study 2 goals & results: Replication & robustness of SCS
Mass Extinction: Life at the Brink
Darwin’s Dangerous Idea
Daily Hollywood Rundown

61. Study 2 goals & results:
Replication & robustness of SCS

62. Study 2 goals & results:
Replication & robustness of SCS

63. WTF? #2: political polarization . . . .

64. Q. Are “curious” partisans more likely to examine surprising contrary evidence?
1. Unsurprising Nonskeptic vs. Surprising Skeptical
2. Surprising skeptic vs. Unsurprising skeptical

65. Nonskeptical

66. Probability of selecting surprising skeptical vs
Probability of selecting surprising skeptical vs. unsurprising nonskeptical story
24% (10%, 45%)
Liberal Dem.
-1 SD science curiosity
N =733. Monte Carlo simulation based on logistic regression. Parenthetical values represent boundaries of 0.95 CI.

67. Probability of selecting surprising skeptical vs
Probability of selecting surprising skeptical vs. unsurprising nonskeptical story
24% (10%, 45%)
68% (46%, 85%)
Liberal Dem.
+1 SD science curiosity
Liberal Dem.
-1 SD science curiosity
N =733. Monte Carlo simulation based on logistic regression. Parenthetical values represent boundaries of 0.95 CI.

68. Probability of selecting surprising skeptical vs
Probability of selecting surprising skeptical vs. unsurprising nonskeptical story
45% (± 31%)
Liberal Dem.
+1 SD science curiosity
Liberal Dem.
-1 SD science curiosity
N =733. Monte Carlo simulation based on logistic regression..

69. Probability of selecting surprising nonskeptical vs
Probability of selecting surprising nonskeptical vs. surprising nonskeptical story
42% (± 31%)
Conserv. Repub.
-1 SD science curiosity
N =733. Monte Carlo simulation based on logistic regression..

70. Probability of selecting surprising nonskeptical vs
Probability of selecting surprising nonskeptical vs. surprising nonskeptical story
42% (± 31%)
Conserv. Repub.
-1 SD science curiosity
62% (± 13%)
Conserv. Repub.
+1 SD science curiosity
N =733. Monte Carlo simulation based on logistic regression..

71. Probability of selecting surprising nonskeptical vs
Probability of selecting surprising nonskeptical vs. surprising nonskeptical story
20% (± 19%)
Conserv. Repub.
-1 SD science curiosity
Conserv. Repub.
+1 SD science curiosity
N =733. Monte Carlo simulation based on logistic regression..

73. Monte carlo simulations
Liberal Democrat (-1 SD on Conservrepub)
high numeracy = 7 correct
low numeracy = 3 correct
Conserv Republican (+1 SD on Conservrepub)
Low numeracy
High numeracy
Avg. “polarization”
on crime data
for low numeracy
partisans
25% (± 9%)
Avg. “polarization”
on crime data
for high numeracy
partisans
46% (± 17%)
crime decreases
crime decreases
crime increases
crime increases
crime increases
crime increases
crime increases
crime decreases
crime decreases
crime decreases
crime decreases
crime decreases
Gun ban
crime increases
crime increases
crime decreases 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100% 0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
probabilility of correct interpretation of data
probabilility of correct interpretation of data

74. Conservative Republican
There is “solid evidence” of recent global warming due “mostly” to “human activity such as burning fossil fuels.” [agree, disagree]
Liberal Democrat
Probability of “agree”
Conservative Republican
Ordinary Science Intelligence (percentile)
N = shaded areas denote 0.95 CIs.

75. Conservative Republican
There is “solid evidence” of recent global warming due “mostly” to “human activity such as burning fossil fuels.” [agree, disagree]
Liberal Democrat
Probability of “agree”
Conservative Republican
Actively Open-minded Thinking (zscore)
N= 750. Derived from logistic regression. Colored barsdenote 0.95 CIs.

76. Conservative Republican
There is “solid evidence” of recent global warming due “mostly” to “human activity such as burning fossil fuels.” [agree, disagree]
Liberal Democrat
Probability of “agree”
Conservative Republican
Cognitive Reflection Test (no. correct)
N = Brackets denote 0.95 CIs.

77. 2 big questions:

78. 2 big questions:
What next?

79. 2 big questions:
What next?
Implications for effective science communication?