A professional who investigates problems concerning growth and development of emotional, mental, physical, and social aspects of individuals, to increase understanding of origins of behavior and processes of human growth and decline. Responsibilities include:

• Formulates hypothesis or research problem and selects or develops method of investigation to test hypothesis.
• Studies behavior of children to analyze processes of learning, development of language in children, and parents' influence on children's behavior.
• Administers intelligence and performance tests to establish and measure patterns of intellectual and psychological growth, development, and decline in children and adults.
• Observes and records behavior of infants to establish patterns of social, motor, and sensory development.
• Analyzes growth of social values and attitudes, using information obtained from observation, questionnaires, and interviews.
• Formulates theories based on research findings for application in such fields as juvenile delinquency, education and guidance of children, parent education, and welfare of aged.
• Experiments with animals (psychologist, experimental), to make comparative studies across species lines to contribute to understanding of human behavior.
• May specialize in study and treatment of children and be designated Child Psychologist.