Psychologists study the human mind and human behavior. Research psychologists investigate the physical, cognitive, emotional, or social aspects of human behavior. Psychologists in health service fields provide mental health care in hospitals, clinics, schools, or private settings.

Psychologists who are employed in business, industry, government, or non-profit organisations are often tasked with providing training, conducting research, designing organisational systems, and acting as advocates for psychology.

Psychologists apply their knowledge to a wide range of endeavours, including health and human services, management, education, law, and sports. They usually specialise in one of a number of different areas.