Psychology is defined as the study of the mind and how it functions in relation to the environment. Psychology relates to many other fields by applying psychological principles. It has helped in education by helping learners learn and teachers teach more effectively. In sociology, social psychology examines how individuals act differently in groups versus alone. Psychology also contributes to medicine through therapeutic measures, to business through improving worker performance and consumer preferences, and to the military through selection and training of personnel. It additionally relates to fields like philosophy, criminology, politics, guidance and counseling, human relationships, law, and more by applying cognitive theories and principles. Understanding the relationships between psychology and other sciences helps solve practical problems involving human behavior and life.