Psychologists may perform a variety of duties in a vast number of industries. For example, those working in health service fields may provide mental healthcare in hospitals, clinics, schools, or private settings. Psychologists employed in applied settings, such as business, industry, government, or nonprofit organizations, may provide training, conduct research, design organizational systems, and act as advocates for psychology. Psychologists apply their knowledge to a wide range of endeavors, including health and human services, management, education, law, and sports. They usually specialize in one of many different areas, such as clinical, school, industrial-organizational, developmental, social, experimental and forensic.
Like other social scientists, psychologists formulate theories, or hypotheses, which are possible explanations for what they observe. But unlike other social science disciplines, psychologists often concentrate on individual behavior and, specifically, in the beliefs and feelings that influence a person’s actions. Psychologists sometimes gather information and evaluate behavior through controlled laboratory experiments, hypnosis, biofeedback, psychoanalysis, or psychotherapy, or by administering personality, performance, aptitude, or intelligence tests. Other methods include interviews, questionnaires, clinical studies, surveys, and observation—looking for cause-and-effect relationships between events and for broad patterns of behavior.