Did IQ Research Cause U.S. Immigration Restriction?
By Bryan Caplan
People who believe in the importance of IQ often conclude that they’ve found a scientific rationale for immigration restrictions. They’re wrong. But has their mistaken inference led to more restrictive immigration policies?
The Immigration Act of 1924 seems like the clearest example. During World War I, IQ researchers found that recent immigrants had below-average IQs. A few years later, lo and behold, the U.S. government imposed new immigration quotas based on the 1890 census, leading to a predictable crash in Southern and Eastern European immigration. Hardly a smoking gun, but certainly suspicious.
After reading Snyderman and Herrnstein’s article, “Intelligence Tests and the Immigration Act of 1924” (American Psychologist, 1983), I’m convinced that this suspicion is incorrect. Contrary to several modern accounts, early IQ researchers never found that 75%+ of Jews, Hungarians, Italians, and Russians were “feeble-minded.” Goddard, the author of the relevant study, was deliberately studying a sub-normal group. He explicitly stated that his study “makes no attempt to determine the percentage of feeble-minded among immigrants in general or even of the special groups named–the Jews, Hungarians, Italians, and Russians.” The standard finding, rather, was that immigrants’ test scores were modestly lower than natives’. And according to Snyderman and Herrnstein, there was no consensus that this modest IQ deficit was hereditary or justified immigration restrictions.
More to the point, though, S&H show that politicians were barely aware of IQ research:
There is no mention of intelligence testing in the Act; test results on immigrants appear only briefly in the committee hearings and are then largely ignored or criticized, and they are brought up only once in over 600 pages of congressional floor debate, where they are subjected to further criticism without rejoinder. None of the major contemporary figures in testing– H. H. Goddard, Lewis Terman, Robert Yerkes, E. L. Thorndike, and so on–were called to testify, nor were any of their writings inserted into the legislative record. The overlapping distributions of test scores for various national and racial populations would probably have created more problems for the Act’s proponents than for its opponents, which may help explain why the intelligence testing movement of the early 20th century left so few traces in the record. The examples of racism occasionally evident in both early psychometric writings and the Immigration Act do not appear to be causally related to each other. Rather, each reflects in its own way a crest in the long history of American Anglo-Saxonism, anti-Catholicism, and anti-Semitism…
My main reservation about Snyderman and Herrnstein’s account: In The Bell Curve, Herrnstein and Murray sound like they want to use IQ research to restrict immigration:
[W]e believe that the main purpose of immigration law should be to serve America’s interests. It should be among the goals of immigration policy to shift the flow of immigrants away from those admitted under nepotistic rules (which broadly encourage the reunification of relatives) and toward those admitted under competency rules, already established in immigration law – not to a total exclusion of nepotistic and humanitarian criteria but a shift. Perhaps our central thought is that present policy assumes an indifference to the individual characteristics of immigrants that no society can indefinitely maintain without danger.
My suspicion is that, despite internal debate, early IQ researchers were indeed anti-immigration. Nevertheless, there were merely a handful of intellectuals. The overwhelming reason why politicians restricted immigration was not psychometrics, but public opinion.