I know that “intelligence quotients” don’t mean anything.
Their theory is that right-wing ideologies attract people with lower mental abilities because they minimize the complexity of the world.
I think this is probably true. Look at the “solutions” right-wingers always give us – soundbites of “school vouchers” and “ban abortion.” And when the left comes up with a solution that actually might work despite complexity, it gets ridiculed by the right; e.g., Bob Dole’s mocking the complex administrative chart of Hilary Clinton’s ~1993 universal health care plan. (I so wanted to transport to the senate floor with a circuit diagram of a TV, and claim “It can’t possibly work!”)
However, just because IQ tests are biased doesn’t mean that there aren’t differences in how people think. Some people seem to be really good at it. Some people don’t. Of course there are many facets to the human mind, in cognition and emotion and so on–and all due to nature and nuture. As @PatRx2 mentioned, low cognition may be an innate inability to solve complex problems, but could be just being uninformed, unimaginative, and/or intellectually lazy. Or a combination of both.
Since it’s so complex, I’m forced to minimize the complexity of the world (as right wingers are prone to do ), but, as when modeling fluid mechanics, for example, I’m trying not to throw away too much. In this simplified model, a racist attitude is the result of at least three basic things – low cognition (innate or taught or whatever) and/or low compassion (for whatever reason; e.g. abusive childhood) and/or knowledge ingrained as a child. I suggest racists who are really intelligent (whatever that means) are probably low in compassion, for whatever reason, regardless of childhood experience. They want power, and don’t care who they hurt (or, more ridiculously, may think no one will be). For those with low cognition, racists may be compassionate, wonderful people to their friends and family, but still be unable to think through the harm that racism causes. Those who have grown up in a racist environment, and have ingrained racist attitudes, have to unlearn them—but levels of cognition and/or compassion may restrict change in their attitudes.
And of course there are exceptions out the wazoo, and different ways of stating this; but it’s basically just a model of how I think about the problem. YMMV. But I submit the correlation in the paper is probably valid, as an approximation. The paper’s abstract states that not much has been done in this area recently, so maybe more work needs to be done – better data and more realistic models.