Review: What Intelligence Tests Miss: The Psychology of Rational Thought (Stanovich, 2009)

MOBI on libgen

I’ve seen this book cited quite a few times and when looking for what to read next, it seemed like on okay choice. The book is written in typical popscience style: no crucial statistical information about the studies is mentioned, so it is impossible for the skeptical reader to know which claims to believe and which not to.

For instance, he spends quite a while talking about how IQ/SAT etc. do not correlate strongly with rationality measures. Rarely does he mention the exact effect size. He does not mention whether it is measured as a correlation of IQ with single item rationality measures. Single items have lower reliability which reduces correlations, and are usually dichotomous which also lowers (Pearson) correlations (simulation results here, TL;DR multiple by 1.266 for dichotomous items). He does not say whether it was university students, which lower correlations as they are selected for g and rationality (maybe). The OKCupid dataset happens to contain a number of items on rationality items (e.g. astrology), I have already noted on Twitter that these correlate with g in the expected direction (religiousness).

Otherwise the book feels like reading Kahneman’s Thinking Fast and Slow. It covers the most well-known heuristics and how they sometimes lead astray (representativeness, ease of recall, framing effect, status quo bias, planning bias, etc.).

The book can be read by researchers with some gain in knowledge, but don’t expect that much. For the serious newcomer, it is better to read a textbook on the topic (unfortunately, I don’t know any, as I have yet to read one myself — regrettably!). For the curious layperson, I guess it is okay.

Therefore, it came as something of a surprise when scores on various college placement exams and Armed Forces tests that the president had taken over the years were converted into an estimated IQ score. The president’s [Bush #2] score was approximately 120-roughly the same as that of Bush’s opponent in the 2004 presidential election, John Kerry, when Kerry’s exam results from young adulthood were converted into IQ scores using the same formulas. These results surprised many critics of the president (as well as many of his supporters), but 1, as a scientist who studies individual differences in cognitive skills, was not surprised.

Virtually all commentators on the president’s cognition, including sympathetic commentators such as his onetime speechwriter David Frum, admit that there is something suboptimal about the president’s thinking. The mistake they make is assuming that all intellectual deficiencies are reflected in a lower IQ score.

In a generally positive portrait of the president, Frum nonetheless notes that “he is impatient and quick to anger; sometimes glib, even dogmatic; often uncurious and as a result ill-informed” (2003, p. 272). Conservative commentator George Will agrees, when he states that in making Supreme Court appointments, the president “has neither the inclination nor the ability to make sophisticated judgments about competing approaches to construing the Constitution” (2005, P. 23)

Seems fishy. One obvious idea is that he has had some kind of brain damage since his recorded score. Since it is based on a SAT score, it is possible that he had considerable help on the SAT test. It is true that SAT prepping does not generally work well and has diminishing returns, but surely Bush had quite a lot of help as he comes from a very rich and prestigious family. (I once read a recent meta-analysis of SAT prepping/coaching, but I can’t find it again. Mean effect size was about .25, which corresponds to 3.75 IQ.)

See also:

Actually, we do not have to speculate about the proportion of high-IQ people with these beliefs. Several years ago, a survey of paranormal beliefs was given to members of a Mensa club in Canada, and the results were instructive. Mensa is a club restricted to high-IQ individuals, and one must pass IQ-type tests to be admitted. Yet 44 percent of the members of this club believed in astrology, 51 percent believed in biorhythms, and 56 percent believed in the existence of extraterrestrial visitors-all beliefs for which there is not a shred of evidence.

Seems fishy too. Maybe MENSA just attracts irrational smart people. I know someone who is in Danish MENSA, so I can perhaps do a new survey.

Rational thinking errors appear to arise from a variety of sources -it is unlikely that anyone will propose a psychometric g of rationality. Irrational thinking does not arise from a single cognitive problem, but the research literature does allow us to classify thinking into smaller sets of similar problems. Our discussion so far has set the stage for such a classification system, or taxonomy. First, though, I need to introduce one additional feature in the generic model of the mind outlined in Chapter 3.

But that is exactly what I will propose. What is the factor structure of rationality? Is there a general factor, is it hierarchical? Is rationality perhaps a second-order factor of g? I get inspiration from study study of ‘Emotional Intelligence’ as a second-stratum factor (MacCann et al, 2014).

The next category (defaulting to the autonomous mind and not engaging at all in Type 2 processing) is the most shallow processing tendency of the cognitive miser. The ability to sustain Type 2 processing is of course related to intelligence. But the tendency to engage in such processing or to default to autonomous processes is a property of the reflective mind that is not assessed on IQ tests. Consider the Levesque problem (“Jack is looking at Anne but Anne is looking at George”) as an example of avoiding Type 2 processing. The subjects who answer this problem correctly are no higher in intelligence than those who do not, at least in a sample of university students studied by Maggie Toplak in my own laboratory.

This sure does sound like a 1 item correct/wrong item correlated with IQ scores from a selected g group. He says “no higher” but perhaps his sample was too small too and what he meant was that the difference was not significant. Samples for this kind are usually pretty small.

Theoretically, one might expect a positive correlation between intelligence and the tendency of the reflective mind to initiate Type 2 processing because it might be assumed that those of high intelligence would be more optimistic about the potential efficacy of Type 2 processing and thus be more likely to engage in it. Indeed, some insight tasks do show a positive correlation with intelligence, one in particular being the task studied by Shane Frederick and mentioned in Chapter 6: A bat and a ball cost $I.Io in total. The bat costs $I more than the ball. How much does the ball cost? Nevertheless, the correlation between intelligence and a set of similar items is quite modest, .43-.46, leaving plenty of room for performance dissociations of the type that define dysrationalia 14 Frederick has found that large numbers of high-achieving students at MIT, Princeton, and Harvard when given this and other similar problems rely on this most primitive of cognitive miser strategies.

The sum of the 3 CRT items (one mentioned above) correlated r=.50 with the 16 item ICAR sample test in my student (age ~18, n=72) data. These items do not perform differently when factor analyzed with the entire item set.

In numerous place he complains that society cares too much about IQ in selection even tho he admits that there is substantial evidence for it works. He also admits that there is no standard test for rationality and cites no evidence that selecting for rationality will improve outcomes (e.g. job performance, GPA in college, prevention of drop-out in training programs), it is difficult to see what he has to complain about. He should have been less bombastic. Yes, we should try rationality measures, but calling for wide scale use before proper validation is very premature.



MacCann, C., Joseph, D. L., Newman, D. A., & Roberts, R. D. (2014). Emotional intelligence is a second-stratum factor of intelligence: Evidence from hierarchical and bifactor models. Emotion, 14(2), 358.