Robert Mearns Yerkes (1876-1956), American psychologist, played a leading role in the development of psychology in America by laying the groundwork for important new areas of both research and practice.

Robert Yerkes was born in Bucks County, Pa., on May 26, 1876. He graduated from Ursinus College in 1892. Financial problems and the offer of a fellowship in zoology at Harvard deflected him from a long-held wish to study medicine. At Harvard he shifted gradually from zoology to animal psychology and received his doctorate in 1902. He remained at Harvard to teach and do research for the next 15 years. In 1916 he was elected president of the American Psychological Association.

As chief of the Psychology Division in the Surgeon General's Office during World War I, Yerkes organized the first large-scale utilization of psychologists in a professional capacity. He developed the Army Alpha Testing Program. This mental screening device, used on 1.7 million recruits, established...