Satoshi Kanazawa is an evolutionary psychologist that currently blogs for Psychology Today in an attempt to give us “a look at the hard truths about human nature”. Â And one of his recent hard-hitting stories is “Why Liberals Are More Intelligent Than Conservatives”. Here’s a snapshot of his evidence:
- He defines Liberalism as altruism toward strangers, people who are not family or friends, by paying taxes to ensure their well-being. HeÂ refers to this altruism as “evolutionarily novel”.
- People who identified as “very liberal” in early adulthood scored (an average of) 12 points higher on a childhood IQ test than those that identified as “very conservative”.
- Look – he even has a graph:
He goes on to point out that conservatives accuse liberals of dominating the media and academia, and concludes they do – because they’re more intelligent.
Well, it’s hard to accept this blog posting at face value. The first criticism that comes to mind is Kanazawa’s assumption that liberal fiscal policy is based on altruism. Next, his complete disregard for the way changes in the size and structure of society have affected us all and the fact that it’s possible the liberal’s life is bettered by paying taxes to ensure the well being of lower income individuals via lower crime, etc. Third, the fact that an IQ test score is wholly based on comparative intelligence and is, by definition, an average. So any sufficiently large sample should test…average. But forget my criticisms – let’s consult someone who actually knows what he’s talking about.
In this article, Dr. Shawn Smith takes Kanazawa to task not for the data he used, but for the way he interpreted it.
Dr. Kanazawa used data obtained in an independent study of 20,745 people performed in three waves from adolescence to early adulthood. The study (lookÂ here,Â Â here, and here) recorded the results of intelligence tests in adolescence and political affiliation in early adulthood. The first wave assessed intelligence using the Peabody Picture Vocabulary Test, and the last wave asked each subject to rate their political affiliation using the continuum in the above graph. It turned out that kidsÂ who scored higher on the intelligence test identified as liberals in early adulthood. Thus, a paper in a psychological journal and the blog post linked above.
Here’s the problem. Wait – here are the problems.
First, the IQ scores Kanazawa used are only an estimate. An estimate based on a verbal intelligence test that may have a decent correlation with the verbal portion of anÂ intelligence test, but not with overall intelligence. There are two major components to most IQ tests: the verbal and the performance portions. So while the scores above may have a high correlation with each child’s verbal ability, they are hardly a picture of each child’s overall intelligence.
Second, and even more problematic, is that kids who score high on the verbal portion of intelligence tests tend to do better in school and continue to college, but may not be more intelligent overall. Equating stronger verbal ability with higher IQ scores skews the study toward the assumption that college students are more intelligent, when that is not necessarily true. (I’ll tell you why this is so problematic in a minute, if you haven’t already figured it out.) Although kidsÂ who score lower on the verbal portion than the performance portion of IQ tests tend to have inferior performance in school and not proceed to college, they are not necessarily less intelligent overall. The discrepancy between these two scores is of high interest to psychologists.
Dr. Smith eloquently sums up this particular criticism, “By relying on a test that merely approximates VIQ [Verbal IQ], Kanazawa ignored a major component of intelligence and hopelessly tainted his data. Had he instead tested subjectsâ€™ ability to rebuild a carburetor, he would have arrived at a different (and equally flawed) pool of â€œmore intelligentâ€ people. Instead, his definition of â€œmore intelligentâ€ is biasedÂ toward those with relatively higher VIQs andÂ away from people with relatively higher PIQs [Performance IQ].”
Last, because Kanazawa’s IQ score skewed the results toward college students as more intelligent, the political party those students selected would inevitably win the intelligence war. And college kids are almost never liberal. Oh wait, yeah they are. College is a time at which people are most likely to be liberal, and academia is an environment that has been objectively shown to be liberal. But to be fair, Dr. Smith consulted a Pew Research study showing that kids between the ages of 18 – 28 (the wave 3 age) identify pretty evenly as democrat or republican. As they get older, they tend to become more conservative. So, these kids were asked to identify their political affiliation at the time in their lives when they’re most likely to be liberal, especially college students (who were deemed to have higher overall intelligence based on a verbal test).
So, in short, the methodology and interpretation that led to Kanazawa’s conclusion that liberals are objectively more intelligent than conservatives is flawed. Dr. Smith even posits that psychologist have a persistent personal agenda to beat up conservatives, and he is determined to fight it. There’s so much good stuff in his article than I couldn’t summarize here, so I’m linking to it again because it’s really worth a read. It’s a real exercise in critical thinking and applied skepticism.
The point isn’t that liberals aren’t more intelligent than conservatives – maybe they are, maybe they aren’t – but this study hasn’t proven it. Â The point is that if the evidence is bad, I have to ignore it – even when it tells me what I want to hear.