 Dr. Schoenfeld's own original contributions in a long research career were influenced by those of B.F. Skinner and Ivan Pavlov.In a carefully devised set of experiments in 1953 he led a team of Columbia University psychologists in discovering that anxiety caused the human heart rate to slow rather than quicken under certain timing of stimuli.He was the co-author with Fred S. Keller, a Columbia colleague, of "Principles of Psychology", an influential college text published in 1950 that emphasized scientific methods in the study of psychology.