Psychology has evolved from the Greek word "psyche," which means "soul" or "mind," and "logos," which means speech. It is an academic and applied field concerning the study of the mind, brain, and behavior, both human and nonhuman. Psychology also refers to the practical application of such knowledge to diverse spheres of human activity, including problems of people's daily lives and the treatment of psychological illness.

Psychology differs from anthropology, economics, political science, and sociology in seeking to capture illustrative generalizations about the mental function and explicit behavior of individuals. However, contrary to this, other disciplines depend more heavily on field studies and historical methods for extracting expressive generalizations. In reality, however, there is much "cross-fertilization" that takes place among different fields. Psychology differs from biology and neuroscience in that it is mainly concerned with the interface between mental processes and behavior of a person. It also refers to the common procedures of a system and not merely the biological or neural procedures themselves.

However, subfields of psychology, such as neuropsychology, combine the study of the actual neural processes with the study of the mental effects they have intuitively produced. Psychology in literal terms means the study of the human mind. It illustrates and attempts to explain awareness, behavior, and social interaction. This study can be structured purely in terms of phenomenological descriptions of internal experiences or as a result of behavior, which includes social conduct. Empirical psychology is mainly dedicated to describing human experience and behavior as it actually occurs.

The study of the correlation between consciousness and the brain or nervous system has been undertaken only recently. However, it is still not clear in what ways they interact.

Psychology is a particularly extensive field, which includes various approaches to the study of mental processes and behavior. An understanding of brain function is gradually being included in psychological theory and practice, particularly in areas such as artificial intelligence, neuropsychological, and cognitive neuroscience. Mechanical and electronic computing has played an important role in developing the information-processing hypothesis of the mind.