Neuropsychologists and Clinical Neuropsychologists

The word psychology derives from the Greek words psyche, meaning soul, and logos, which is knowledge or study. Thus, psychology is the study of the soul. Early philosophers such as Plato called attention to the differences between body and soul, while scholars today tend to emphasize the unity between mind and body. The study of the relationship between the brain and behavior, now known as neuropsychology, also dates to the early Greeks, with Hippocrates' belief that the brain had a direct effect on behavior.

Wilhelm Wundt, a physician, founded experimental psychology in the late 1870s. German scholars followed Wundt's approach to scientific methods in psychology, and discovery by experiment was considered the only respectable way for learned thinkers to work. It was considered normal practice when, in 1879, Wundt set up an experimental laboratory to conduct research on human behavior. Many famous psychologists in the United States trained with Wundt.

In the early 1900s, Russian physiologist Ivan Pavlov discovered a key aspect of behaviorist theory while studying the process of digestion. He was experimenting on dogs when he found that they began to salivate in anticipation of their food. He rang a bell before presenting their meat, and discovered the dogs associated the sound of a bell with mealtime. He would then ring the bell without giving them food. The dogs salivated 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.

Sigmund Freud was also a major innovator in the field of psychology, with much of his work forming the basis for modern theories of behavior. His work on the meaning of dreams, the unconscious, and the nature of various emotional disturbances has had a profound effect on the profession and practice of psychology for more than 85 years, although many psychologists now disagree with some of his theories.

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

Neuropsychology is a specialized field of psychology, emerging in the late 1800s. Today, neuropsychologists evaluate people's neurological functioning in relation to their mental health. They study the nervous system, including the brain and spine, and help diagnose and treat brain conditions, such as Alzheimer's and traumatic brain injuries. Some may also treat people with dyslexia.