John B. Watson

John Broadus Watson was born January 9, 1878, and by 1913 had drawn a line in the sand at Columbia University with an address that redefined psychology as the study of observable behavior alone. He edited Psychological Review from 1910 to 1915 while running experiments that ranged from animal studies to the infamous "Little Albert" test, conditioning an infant to fear a white rat. After psychology, he turned the same principles to advertising and child-rearing advice. A 2002 survey ranked him the 17th most cited psychologist of the 20th century. He died September 25, 1958, having spent decades watching behaviorism - his creation - split the field he'd tried to unify.