Applied psychology is the use of psychological methods and findings of scientific psychology to solve practical problems of human and animal behavior and experience. Mental health, organizational psychology, business management, education, health, product design, ergonomics, and law are just a few of the areas that have been influenced by the application of psychological principles and findings. Some of the areas of applied psychology include clinical psychology, counseling psychology, evolutionary psychology, industrial and organizational psychology, legal psychology, neuropsychology, occupational health psychology, human factors, forensic psychology, engineering psychology, school psychology, sports psychology, traffic psychology, community psychology, medical psychology. In addition, a number of specialized areas in the general field of psychology have applied branches (e.g., applied social psychology, applied cognitive psychology). However, the lines between sub-branch specializations and major applied psychology categories are often blurred. For example, a human factors psychologist might use a cognitive psychology theory. This could be described as human factor psychology or as applied cognitive psychology.
Psychology is the science of behavior and mind, including conscious and unconscious phenomena, as well as feeling and thought. It is an academic discipline of immense scope and diverse interests that, when taken together, seek an understanding of the emergent properties of brains, and all the variety of epiphenomena they manifest. As a social science it aims to understand individuals and groups by establishing general principles and researching specific cases.
Psychology consists of describing states of the soul by displaying them all on the same plane, without any discrimination of value, as though good and evil were external to them, as though the effort toward the good could be absent at any moment from the thought of any man.
Simone Weil, “The responsibility of writers,” On Science, Necessity, and the Love of God, R. Rees, trans. (1968), p. 168
How is property given? By restraining liberty; that is, by taking it away so far as necessary for the purpose. How is your house made yours? By debarring every one else from the liberty of entering it without your leave.
Jeremy Bentham, "A Critical Examination of the Declaration of Rights; Article II" in The Works of Jeremy Bentham, Vol. II (1839), p. 503.