Joseph Jastrow

Born in Warsaw on January 30, 1863, he came to the United States as a child and was educated in Philadelphia before earning a doctorate at Johns Hopkins University. He became one of the early builders of American psychology and went on to establish the psychology laboratory at the University of Wisconsin, where he taught for many years.

His work ranged across experimental psychology, psychophysics, and the study of perception. He had a special gift for explaining mental quirks in ways ordinary readers could enjoy, and his name became closely linked with optical illusions and with efforts to test extraordinary claims using careful evidence rather than wishful thinking.

Beyond the classroom, he wrote extensively for the public, helping popularize psychology in newspapers, magazines, and books. That mix of scientific curiosity, skepticism, and showmanship made him an unusually visible psychologist in his time, and it still gives his work an accessible, lively appeal today.