Psychology is defined as the science of behavior and mental processes. It studies cognition, brain activity, mental functions, and how these influence individual and social behavior. Psychologists explore concepts like perception, cognition, emotion, and motivation. They conduct both qualitative and quantitative research using the scientific method. Some subfields of psychology include clinical, biological, industrial, organizational, social, and developmental psychology. In conclusion, psychology is an important science that studies human behavior individually and in groups, and plays a role in society by involving concepts related to mental health, biology, and other factors that define individuals physically, socially, and spiritually.