Psychologists are the scientists of human behavior and mental processes.
They approach these areas from a variety of perspectives. Cognitive psychologists are interested in how knowledge and behavior are acquired, retained, and retrieved. Developmental psychologists study physical, cognitive and social changes that occur throughout an individual's life. Clinical psychologists seek to identify the causes of abnormal behavior and to change these behaviors so their clients can live more satisfying and rewarding lives. Only by understanding all of these viewpoints can psychologists appreciate fully the complexity of human behavior.