In Kahan’s experiment, some people were asked to interpret a table of numbers about whether a skin cream reduced rashes, and some people were asked to interpret a different table – containing the same numbers – about whether a law banning private citizens from carrying concealed handguns reduced crime. Kahan found that when the numbers in the table conflicted with people’s positions on gun control, they couldn’t do the math right, though they could when the subject was skin cream. The bleakest finding was that the more advanced that people’s math skills were, the more likely it was that their political views, whether liberal or conservative, made them less able to solve the math problem.
The rash cream experiment is a randomized trial, whereas the concealed-weapon ban is not. That’s not enough to explain away the effect, but is consistent with the hypothesis that people put more weight on priors in confusion situations (and people who are better at math find the gun control scenario relatively more confusing).
The bleakest finding was that the more advanced that people’s math skills were, the more likely it was that their political views, whether liberal or conservative, made them less able to solve the math problem.
So, my first thought was that this might be a trivial statement. If any person is 30% likely to give the wrong answer for partisan reasons, but the chance of getting it wrong depends on innumeracy, then partisanship will be the dominant reason for error among highly numerate people, because it’s basically the only source of error, even though total error is lower.
But turns out this is a rather meaningful statement (as shown by Figure 6 of the paper). Among liberals, numeracy has basically no impact on whether or not they correctly answered the political question when it disagreed with their priors (which is, frankly, horrifying). Conservatives who scored 8 or 9 (the max score) on numeracy were slightly better at giving the answer that went against their political position than less numerate conservatives, but only slightly. When the answer supported by the data supports the expected preconceived notion, both conservatives and liberals saw a positive relationship between numeracy and giving the correct answer. (Oddly, for conservatives the relationship looks linear, but for liberals it’s flat-ish then sharply positive.)
That seems odd. What’s the difference between being handed a a list of numbers that support gun control being useless and being handed a list of numbers that you misinterpret as supporting gun control being useless?
I would have expected numeracy to be completely independent of the answer....
direct link to paper
Relevant quote from popular source:
The rash cream experiment is a randomized trial, whereas the concealed-weapon ban is not. That’s not enough to explain away the effect, but is consistent with the hypothesis that people put more weight on priors in confusion situations (and people who are better at math find the gun control scenario relatively more confusing).
So, my first thought was that this might be a trivial statement. If any person is 30% likely to give the wrong answer for partisan reasons, but the chance of getting it wrong depends on innumeracy, then partisanship will be the dominant reason for error among highly numerate people, because it’s basically the only source of error, even though total error is lower.
But turns out this is a rather meaningful statement (as shown by Figure 6 of the paper). Among liberals, numeracy has basically no impact on whether or not they correctly answered the political question when it disagreed with their priors (which is, frankly, horrifying). Conservatives who scored 8 or 9 (the max score) on numeracy were slightly better at giving the answer that went against their political position than less numerate conservatives, but only slightly. When the answer supported by the data supports the expected preconceived notion, both conservatives and liberals saw a positive relationship between numeracy and giving the correct answer. (Oddly, for conservatives the relationship looks linear, but for liberals it’s flat-ish then sharply positive.)
That seems odd. What’s the difference between being handed a a list of numbers that support gun control being useless and being handed a list of numbers that you misinterpret as supporting gun control being useless?
I would have expected numeracy to be completely independent of the answer....