Skip to Main Content



The first syllable in psychology derives from psyche, a Greek word meaning soul. The second half of psychology contains the root of the word logic. Thus, psychology translates as "the science of the soul."

Early philosophers emphasized differences between body and soul. Plato, for example, believed they were two entirely different parts. Modern scholars tend to emphasize the unity between mind and body rather than their dissimilarity.

The founder of experimental psychology, Wilhelm Wundt, held both an M.D. and a Ph.D. A physician, he taught at the University of Leipzig, where his title was professor of philosophy. Like Wundt, German scholars of the 19th century were committed to the scientific method. Discovery by experiment was considered the only respectable way for learned thinkers to work. Thus it was not thought strange that in 1879, Wundt set up an experimental laboratory to conduct research on human behavior. Many people who later became famous psychologists in the United States received their training under Wundt.

At the turn of the 20th century, Russian physiologist Ivan Pavlov discovered a key aspect of behaviorist theory while studying the process of digestion. While experimenting on dogs, he found that they began to salivate in anticipation of their food. He discovered that if he rang a bell before presenting their meat, the dogs associated the sound of a bell with mealtime. He then would ring the bell but withhold the food. The dogs' saliva flowed anyway, whether or not they saw or smelled food. Pavlov called this substitute stimulus a "conditioned response." Many psychologists began to incorporate the theory of conditioned response into their theories of learning.

One of the most famous pioneers in psychology was Sigmund Freud, whose work led to many of the modern theories of behavior. Freud lived and practiced in Vienna, Austria, until Hitler's forces caused him to flee to England. His work on the meaning of dreams, the unconscious, and the nature of various emotional disturbances has had a profound effect upon the profession and practice of psychology for more than 70 years, although many psychologists now disagree with some of his theories.

Many Americans have contributed greatly to the science that seeks to understand human behavior: William James, Robert Woodworth, E. L. Thorndike, Clark Hull, B. F. Skinner, and others.

Related Professions