The fracas over Don Lemon of CNN laughing at his panel's insults about the intelligence of Trump supporters raises a larger issue: the ignorant belief that Trump supporters are much dumber than the general public and much dumber than those who supported Clinton in 2016. Don Lemon and his guests specifically ridiculed Trump supporters for supposed problems with "readin'" and "geography" (e.g., picking out Ukraine on a map).

Even without looking at the data, it would be surprising if there were any VERY LARGE differences in intelligence between the average Trump supporter and the rest of the general public.

INTELLIGENCE OF TRUMP SUPPORTERS

We don't have great data on the intelligence of Trump supporters, but the best available is in the 2018 General Social Survey. For those unfamiliar with the GSS, it is usually regarded as the leading omnibus academic survey in the US; it usually achieves response rates about 10 to 20 times higher than the typical public opinion poll.

In 1974, the GSS adopted a 10-question vocabulary test (WORDSUM) that was extracted from a standard, widely used IQ test. The National Science Foundation (NSF), in its 2018 report on science knowledge, refers to this battery of GSS items as a "verbal ability" test.

In the 2018 GSS, respondents were asked for whom they voted in 2016 (PRES16) or for whom they would have voted if they had voted (IF16WHO): Clinton, Trump, someone else, or no one.

On the verbal ability test (WORDSUM), not surprisingly the median number of vocabulary questions correct was the same for both Clinton and Trump supporters: 6 out of 10 words correct. The mean verbal ability score for Trump supporters was 6.15 words correct, while the mean verbal ability score for Clinton supporters was 5.69 correct, a difference of nearly a half a question on a 10-question test. This moderate difference is statistically significant at p<.0005.

Further, Trump supporters score significantly higher on verbal ability (6.15 correct) than the rest of the public combined (5.70 correct), whereas Clinton supporters score significantly lower on verbal ability (5.69 correct) than the rest of the public combined (5.98 correct).

This should not be too surprising. On the 22 General Social Surveys using the verbal ability scale since 1974, for every single one, conservative Republicans score significantly higher than the rest of the public combined. As for Republicans overall, they score significantly higher in verbal ability than Democrats in all five decades, including for the 2010s combined.

But the Trump era is helping Democrats to catch up: the Republican advantage dropped to insignificance in 2016, and in 2018 Democrats (6.03 correct) actually scored slightly (but insignificantly) higher than Republicans (5.98 correct).

In 199[4], the GSS employed another module lifted from a standard IQ test, one testing analogical reasoning. Again, Republicans and conservative Republicans in 199[4] performed significantly better on analogical reasoning than the rest of the public and significantly better than Democrats.

TRUMP SUPPORTERS' KNOWLEDGE OF SCIENCE

These results on verbal ability are also consistent with the results of most (but not all) of the National Science Foundation's science knowledge questions on the GSS.

Testing the hypothesis that Trump supporters have greater science knowledge than those who supported Clinton in 2016, on six questions Trump supporters offer the correct answer significantly more often than Clinton supporters: those about lasers, radioactivity, viruses, the father's contribution to the biological sex of the child (BOYORGRL), whether "according to astronomers" the universe began with a huge explosion (BIGBANG1), and that the earth goes around the sun and that it takes a year to do so (combined EARTHSUN and SOLARREV).

On one science knowledge question—whether the center of the earth is hot (HOTCORE)—the superior performance of Trump supporters over Clinton supporters is borderline significant (1-sided Fisher's Exact Test p=.05-.10).

On two questions, the structure of atoms (ELECTRON) and continental drift (CONDRIFT), Trump supporters score slightly, but insignificantly, better than Clinton supporters. On none of these nine science questions do Trump supporters score worse than Clinton supporters.

When one compares Clinton supporters to the rest of the public combined, Clinton supporters perform significantly worse than the rest of the public on the same six science questions on which Trump supporters perform better than Clinton supporters.

Indeed, less than half of 2016 Clinton supporters (49.6%) are able to answer correctly both of two related questions: whether the earth goes around the sun or the sun goes around the earth (EARTHSUN) and whether that takes a day, a month, or a year (SOLARREV). Remember these two questions are multiple choice! You would have a 50-50 chance of guessing correctly on the first part: whether the earth goes around the sun or vice versa. Sadly, the general public didn't do hugely better than Clinton supporters, with only 57.1% (compared to 49.6%) knowing that the earth goes around the sun and that it takes a year to do so.

When one compares Trump supporters to all the rest of the public combined (rather than just to Clinton supporters), the pattern for these nine science questions is roughly similar (though weaker).

Overall, on most science knowledge questions Trump supporters score significantly higher than Clinton supporters and significantly higher than the combined non-Trump supporting public. If, however, you asked about beliefs, rather than knowledge, on evolution and the origins of the universe you would get substantially better answers on individual science questions from Clinton supporters than Trump supporters.

MAP-READING

As for reading maps and picking out countries, which the CNN segment raised, I searched quickly and found two Pew surveys from 2013 that asked respondents to pick out Egypt or Syria on a map of the Middle East. Testing the hypothesis that Republicans were significantly better at finding an unlabeled country on a map than Democrats, one 2013 Pew study supported that hypothesis (Republicans were indeed significantly more likely to pick out Syria on a map), while the other 2013 Pew study reported that Democrats were insignificantly better at picking out Egypt on a map.

Thus, neither of these two studies supports the CNN's panel's ridicule of right-wing map reading, and there is some weak evidence pointing in the other direction. Of course, this was a test of Republicans, not Trump supporters, but Trump supporters did better on the 2018 GSS verbal ability test and on 2018 science knowledge questions, so there is no strong reason to suppose that the results would be radically different if one were to test Trump supporters today rather than Republicans in 2013. In 2013 the differences were not large either way, and it's unwarranted to suppose that (in a study of the quality of the GSS) any differences in map-reading would be large today.

IGNORANCE LEADS TO BIGOTRY

Don Lemon laughed uncontrollably at his guests insulting the intelligence and knowledge of Trump supporters. The best evidence we have suggests that, compared to the general public, Trump supporters score significantly better than the rest of the public—and Clinton supporters score significantly worse—on a standard verbal ability test. Likewise, Trump supporters score significantly better on most science knowledge questions than Clinton supporters or the general public.

In this essay, I analyzed the results of over 30 questions from 22 different representative national surveys, involving over 20,000 respondents. Not one of the questions I examined here supports the idea that Trump supporters are significantly less knowledgeable than Clinton supporters, and some of them point to small or moderate differences in the opposite direction. The idea that there are very large differences in intelligence or knowledge here is implausible without strong evidence.

In short, Don Lemon is a bigot—and like most bigots, he's an ignorant one as well.

[Disclosure: The author made a small donation to the Hillary Clinton campaign in the fall of 2016.]

[Research Note: General Social Survey data were downloaded from NORC. GSS data are weighted by WTSALL. On science questions, I coded the correct answers v. those who gave wrong answers, said they don't know, or failed to answer. The Pew data were downloaded from the IPOLL database at the Roper Center, and the WEIGHT variable was used. For 2x2 tables, significance was determined by 1-tailed Fisher Exact tests. For differences of means, 1-sided independent T-Tests were used without assuming equal variances.]