Psychology is the science concerned with behavior, in both human and nonhuman animals. Despite its youth, it is a broad discipline, essentially spanning subject matter from biology to sociolog.
A psychologist is a professional who evaluates and studies behavior and mental processes. Psychologists have doctoral degrees. They study the intersection of two critical relationships: one between brain function and behavior, and another between the environment and behavior. As scientists, psychologists follow scientific methods, using careful observation, experimentation and analysis. But psychologists also need to be creative in the way they apply scientific findings.
For more details, PS: https://bit.ly/2wPBlWG