Cyril Burt fabricated IQ twin data — the most famous fraud in psychology

Sir Cyril Burt (1883–1971) was the most influential British psychologist of his generation, knighted in 1946 and appointed to the first chair of psychology at University College London. His most cited work was a series of twin studies on the heritability of intelligence, which reported remarkably high IQ correlations for identical twins reared apart — a key piece of evidence for the genetic basis of intelligence.

After Burt's death, the data began to unravel. In 1974, psychologist Leon Kamin noticed that Burt's correlation coefficients were identical to three decimal places across multiple papers when the sample size supposedly grew. In 1976, Sunday Times journalist Oliver Gillie could not trace two of Burt's co-authors — Margaret Howard and J. Conway — at any University of London institution. Burt's housekeeper recalled Burt saying they had 'done the research' but 'emigrated'. Burt's official biographer, Leslie Hearnshaw, concluded in 1979 that most of Burt's post-war data were fraudulent.

The scandal — known as 'the Burt Affair' — profoundly damaged behavioral genetics and the study of intelligence. Funding dried up, the field was stigmatized for a generation, and Burt's name became a byword for scientific fraud. His notes and records had been burned shortly after his death, making it impossible to fully reconstruct what was fabricated. The case remains the most famous example of research fraud in psychology.