Nov 7, 2025·Advanced Topics & ResearchDo Past Controversies Taint Modern Research on Intelligence?
It traces the global spread and persistence of eugenic ideas through the 20th century, showing how modern genetics and technologies echo past debates about heredity and human improvement.
Dr. Russell T. WarneChief Scientist

Critics of intelligence testing often attempt to discredit current practices by linking them to the field's troubling origins. While supporters of standardized testing like the SAT cannot dismiss its problematic history—created by Carl Campbell Brigham, an avowed eugenicist who believed intelligence was genetically determined by race—this connection does not necessarily taint modern research.
Shakespeare wrote that "What's past is prologue," acknowledging history's influence on present events. This principle applies to science, where discoveries build upon earlier theories and data. Intelligence research evolved from its predecessors: Binet's 1905 test emerged after a decade of studying child cognitive development and was shaped by European debates about intellectual disabilities.
However, the past need not imprison the present. Scientific ideas undergo constant reevaluation, and failed theories get discarded—a vital aspect of scientific progress. Unfortunately, some critics fail to recognize this distinction, attempting to smear contemporary intelligence research by associating it with historical errors.
Eugenics and Early Intelligence Research
Intelligence research became entangled with eugenics early on. Sir Francis Galton, who pioneered scientific intelligence measurement, coined the term "eugenics" in 1883, meaning "well born." Inspired by his relative Charles Darwin's work on natural selection, Galton believed humans should control their own evolution by encouraging "superior strains" to reproduce while preventing "undesirable" individuals from doing so.
Galton's ideas spread globally, with eugenics societies forming across Europe, the Americas, and Asia. Different nations implemented varying approaches. The United States pioneered forced sterilization in 1907, eventually sterilizing approximately 60,000 individuals by the twentieth century's end. Scandinavian countries used eugenics to reduce welfare burdens. Germany's notorious 1930s-1940s program, based on American laws, sterilized over 350,000 citizens before expanding to euthanasia and ultimately the Holocaust.
Early intelligence researchers were undeniably eugenic advocates. Henry Goddard published case studies supposedly demonstrating the hereditary nature of "feeble-mindedness." Lewis Terman, creator of the Stanford-Binet test, declared that intelligence testing would identify "high-grade defectives" and curtail reproduction of "feeble-mindedness." Most early intelligence researchers, including SAT creator Brigham, endorsed racially-biased forms of eugenics. Terman called intelligence testing "the beacon light of the eugenics movement."
Eugenics: Then and Now
Critics attempting to connect early eugenic researchers to modern scientists oversimplify historical realities. Eugenic beliefs were widespread among early twentieth-century elites across numerous fields—not just psychology. Prominent supporters included H.G. Wells, Winston Churchill, Theodore Roosevelt, and many other luminaries. The Catholic Church provided the most organized resistance.
Condemning modern intelligence research for its field's eugenic connections applies flawed guilt-by-association logic. By this reasoning, anyone enjoying H.G. Wells's science fiction endorses his eugenic views, or using the Gini coefficient endorses Corrado Gini's eugenics. Such arguments are absurd. Culture functions as a buffet—future generations may adopt useful ideas while rejecting harmful ones.
Additionally, psychologists held minimal influence in historical eugenics movements. Leading eugenicists were predominantly physicians, biologists, and social reformers. Nazi Germany actually opposed intelligence research as too theoretical.
Eugenics did not immediately disappear after World War II. American forced sterilizations continued into the 1970s, with laws remaining on books until the 1980s. Japan repealed its eugenic sterilization law in 1996. Modern practices like genetic counseling, selective abortion, and gene editing represent eugenic effects, though without using that terminology.
Importantly, pioneering psychologists who advocated eugenics later renounced the movement. Brigham and Goddard publicly recanted, while Terman quietly withdrew support, as scientific assumptions underlying eugenics proved incorrect.
The past influences but does not bind the present. While intelligence research has an ugly history, modern research focuses on different questions, and historical lessons can help prevent repeating earlier tragedies.
From Chapter 32 of "In the Know: Debunking 35 Myths About Human Intelligence" by Dr. Russell Warne (2020)
AuthorDr. Russell T. WarneChief Scientist