IQ is largely a pseudoscientific swindle

By Nassim Nicholas Taleb

Background : “IQ” is a stale test meant to measure mental capacity but in fact mostly measures extreme unintelligence (learning difficulties), as well as, to a lesser extent, a form of intelligence, stripped of 2nd order effects. It is meant to select exam-takers, paper shufflers, obedient IYIs (intellectuals yet idiots), ill adapted for “real life”. The test is poorly thought out mathematically, and seemed to be promoted by

  • racists/eugenists, people bent on showing some populations have inferior mental abilities based on IQ test=intelligence who have been upset with me for suddenly robbing them of a “scientific” tool (as evidenced by the bitter reactions to the initial post on twitter/smear campaigns by such mountebanks as Charles Murray). (Note: there were close to 3.1 million views of the tweetstorms).
  • psychometrics peddlers looking for suckers (military, large corporations) buying the “this is the best measure in psychology” argument when it is not even technically a measure — it explains at best between 13% and 50% of the performance in some tasks, minus the data massaging and statistical cherrypicking by psychologists; it doesn’t satisfy the monotonicity and transitivity required to have a measure. No measure that fails 60–95% of the time should be part of “science”.
Fig 1: The graph that summarizes the flaw, showing that “correlation” is meaningless in the absence of symmetry. We construct (in red) an intelligence test (horizontal), that is 100% correlated with negative performance (when IQ is, say, below 100) and 0% with upside, positive performance. We progressively add noise (with a 0 mean) and see correlation (on top) drop. Performance is on the vertical axis. The problem gets worse with the “g” intelligence based on principal components. By comparison we show (graph below) the distribution of IQ and SAT scores. Most “correlations” entailing IQ suffer the same pathology. Note that IQ tests correlate with SAT scores!

Some argue that IQ measures intellectual capacity, not “wisdom” or patience, or “conscienciousness”, or decision-making or something of the sort. No. It does not measure intellectual capacity

If you want to detect how someone fares at a task, say loan sharking, tennis playing, or random matrix theory, make him/her do that task; we don’t need theoretical exams for a real world function by probability-challenged psychologists. Traders get it right away: hypothetical P/L from “simulated” paper strategies don’t count. Performance=actual. What goes in people’s head or reaction to a screen image doesn’t exist (except via negativa).

Fat Tails If IQ is Gaussian by construction and if real world performance were, net, fat tailed (it is), then either the covariance between IQ and performance doesn’t exist or is uninformational. It will show a finite number in sample but doesn’t exist statistically. Another problem when “black people are x standard deviations away”. Different populations have different variances, even different skewness and these comparisons require richer models. See the formal treatment in my next book.

Mensa members: typically high “IQ” losers in Birkenstocks.

But the “intelligence” in IQ is determined by academic psychologists like “paper trading”, via statistical constructs s.a. correlation that I show here (see Fig. 1) that they patently don’t understand. It does correlate to negative performance (as it was initially designed to detect learning special needs) but then any measure would work there. A measure that works in left tail not right tail (IQ decorrelates as it goes higher) is problematic. We have gotten similar results since the famous Terman longitudinal study, even with massaged data for later studies. (To get the point, consider that if someone has mental needs, there will be 100% correlation between performance and IQ tests. But the performance doesn’t correlate as well at higher levels, though the psychologists will think it does.)

It is a false comparison to claim that IQ “measures the hardware” rather than the software. It can measures some arbitrarily selected mental abilities (in a testing environment) believed to be useful. However, if you take a Popperian-Hayekian view on intelligence, you would realize that to measure it you would need to know the mental skills needed in a future ecology, which requires predictability of said future ecology. It also requires the skills to make it to the future (hence the need for mental biases for survival).

Real Life: In academia there is no difference between academia and the real world; in the real world there is. 1) When someone asks you a question in the real world, you focus first on “why is he/she asking me that?”, which shifts you to the environment (see Fat Tony vs Dr John in The Black Swan) and detracts you from the problem at hand. Only suckers don’t have that instinct. 2) Real life never never offers crisp questions with crisp answers (most questions don’t have answers; perhaps the worst problem with IQ is that it seem to selects for people who don’t like to say “there is no answer, don’t waste time, find something else”.) 3) It takes a certain type of person to waste intelligent concentration on classroom/academic problems. These are lifeless bureaucrats who can muster sterile motivation. Some people can only focus on problems that are real, not fictional textbook ones (see the note below where I explain that I can only concentrate with real not fictional problems). 4) IQ doesn’t detect convexity (by an argument similar to bias-variance you need to make a lot of small inconsequential mistake in order to avoid a large consequential one. See Antifragile and how any measure of “intelligence” w/o convexity is sterile…). To do well you must survive, survival requires some mental biases directing to some errors. 5) Fooled by Randomness: seeing shallow patterns in not a virtue — leads to naive interventionism. Some psychologist wrote back to me: “IQ selects for pattern recognition, essential for functioning in modern society”. No. Not seeing patterns except when they are significant is a virtue in real life. 6) To do well in life you need depth and ability to select your own problems and to think independently.

Upper bound: discount the massaging and correlation effects. Picked up from the highly unrigorous Intelligence: All That Matters by S. Ritchie.

Functionary Quotient: If you renamed IQ , from “Intelligent Quotient” to FQ “Functionary Quotient” or SQ “Salaryperson Quotient”, then some of the stuff will be true. It measures best the ability to be a good slave. “IQ” is good for @davidgraeber’s “BS jobs”.

Metrification: If someone came up w/a numerical“Well Being Quotient” WBQ or “Sleep Quotient”, SQ, trying to mimic temperature or a physical quantity, you’d find it absurd. But put enough academics w/physics envy on it and it will become an official measure.

IQ” is most predictive of performance in military training, w/correlation~.5, (which is circular since hiring isn’t random).

  • I have here no psychological references for backup: simply, the field is bust. So far ~ 50% of the research DOES NOT replicate, & papers that do have weaker effect. Not counting poor transfer to reality.
  • How P values often fraudulent:…
  • The Flynn effect should warn us not just that IQ is somewhat environment dependent, but that it is circular.
  • Verbalism: Psychologists have a skin-deep statistical education & can’t translate something as trivial as “correlation” or “explained variance” into meaning, esp. under nonlinearities (see paper at the end).
  • IQ is reminiscent of risk charlatans insisting on selling “value at risk” and RiskMetrics saying “it’s the best measure”. That “best” measure, being unreliable blew them up many many times.
  • You can’t do statistics without probability.
  • Much of the stuff about IQ of physicists is suspicious, from self-reporting biases/selection in tests.
  • If you looked at Northern Europe from Ancient Babylon/Ancient Med/Egypt, you would have written the inhabitants off.. Then look at what happened after 1600.
  • The same people hold that IQ is heritable, it determines success, that Asians have higher IQs than Caucasians, degrade Africans, then don’t realize that China for about a Century had one order of magnitude the GDP of the West.

CURSE OF DIMENSIONALITY A flaw in the attempts to identify “intelligence” genes. You can get monogenic traits, not polygenic (note: additive monogenic used in animal breeding is NOT polygenic).

Note From Skin in the Game, 1
Note from Skin in the Game, 2