Measurement of Intelligence, Eugenics, and the Theory of Second-Best

Recently, I added a new field to my list of interests–intelligence (which consequently was already the topic of a post here). A few weeks ago I stumbled upon a book by the Fortune columnist Daniel Seligman, titled A Question of Intelligence: The IQ Debate in America. It was published in 1992, but a quick internet research reveals that the state-of-the-art in psychometrics has not changed much since. Regarding facts and their causal interpretations, the book is quite balanced–although it might be worthwhile to combine it with Malcolm Gladwell’s Outliers to get an even more balanced perspective. Where I do not agree with Seligman at all is in the area of political implications, particularly in the context of eugenics.

Let us start with some basic patterns identified in psychometric research over the last few decades. There is more or less general agreement according to the following statements:

  • Intelligence can be measured in an acceptably accurate and encompassing way by means of specialized IQ tests (not to be confused with those simplistic tests you can find in newspaper kiosks and conduct yourself).
  • Intelligence is highly correlated with numerous measures of “success”, including income and occupational status.
  • Intelligence is the result of the influence of both genetic and environmental factors, with the relative importance of the two at around 2:1.
  • There are significant differences in IQ both within and between populations. E.g., Afroamericans score significantly lower on average than whites, who score lower than East-Asians. There is still much controversy as to what are the underlying reasons.
  • It is unclear whether average IQ in wealthy countries is rising (the so-called Flynn hypothesis) or falling. However, given IQ’s predominantly genetic nature and the fact that in wealthy countries the rich (and, on average, more intelligent) people exhibit significantly lower fertility rates than the poor, it should be expected that average IQ will decline, at least in the long term (in the short term environmental factors might outweigh this effect).

The latter point is in effect the reason why eugenics came up in the late 19th century. The idea was simple (and highly influential among the intellectual elite of that time, including H. G. Wells or George Bernard Shaw): let us encourage the multiplication of “societally desirable” characteristics and restrict the multiplication of those we do not want (e.g., through sterilization programmes).

Mr Seligman found the general idea behind eugenics good. He did not explicitly pledge in favour of such drastic measures as sterilization, but he showed much enthusiasm for prenatal screening and, in effect, “genetic design” of one’s offspring. The noble goal of such measures would be societal progress towards a more intelligent, healthy and productive future. The issue of the technical feasibility of such a programme notwithstanding, I would like to raise two points of critique. The first objection is more a question and cannot be answered objectively: What is it that makes a good society? What are the most valuable contributions individuals make to such a society? Apparently, Seligman’s and my opinions on that differ, since I do not think that “productivity” or intelligence count that much (see here).

The second objection appears more important for it is much more objective. Seligman seems to implicitly assume that prenatal “design” would not have negative spillovers, such as increased stratification of the society and increased dissatisfaction of those who do not carry societally “valuable” genetic material. Together, these effects might undermine the transition towards the “good society” Seligman envisions. If such psychological reactions would not come up, his eugenic approach might be worth considerations. It they would, however, which appears much more likely, we have here a classic second-best problem.

The economic theory of second best, outlined in the 1950’s by Lipsey and Lancaster, shows that if a first-best solution (here: Seligman’s envisioned “intelligent” society, without transitional problems resulting from stratification, envy and lowered self-esteem) is not attainable because of an insurmountable market failure (here: “human nature”), then it is not optimal to proceed as if there would be no market failure–what might be called the “naive second-best approach”. Rather, commitment to additional market failures (here: refraining from prenatal “design” and, possibly, from comprehensive measurement of intelligence) might be necessary to reach social optimum–what might be called the “pragmatic second-best approach”.

Even if one unlike me shares Seligman’s vision of an ideal society, the theory of second-best provides a strong argument against his pro-eugenics view of what are the implications of the state-of-the-art in psychometric research. Furthermore, it undermines, in an analogous manner, the rationale behind the well-meant calls for universal measurement of intellectual abilities. Of course, there are many more arguments that might be envoked against Seligman and those who think similarly about psychometrics–some can be found in Gladwell’s Outliers or in my earlier post on intelligence. In the end, they boil down to the appreciation of the fact that human-beings are much more complicated than suggested by simple IQ figures.



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