Harry L. (Harry Levi) Hollingworth

Born in De Witt, Nebraska, in 1880, Harry Levi Hollingworth became one of the early American psychologists to build a bridge between academic research and practical problems outside the classroom. He studied at the University of Nebraska and later earned his Ph.D. at Columbia University, where he spent much of his career.

Hollingworth is especially remembered for helping shape applied psychology. He worked on questions of advertising and vocational testing, and he also carried out well-known research on the effects of caffeine. His writing and teaching helped show that psychology could be useful not only in laboratories, but also in business, education, and public life.

He was also part of an important intellectual partnership with psychologist Leta Stetter Hollingworth, and he later wrote a biography of her. Over the course of his career, he published widely and served as president of the American Psychological Association, leaving a lasting mark on the development of modern psychology.