The human psyche is the mind or soul. It is the center of an individual's emotions, thought and behavior. The psyche controls the individual's response to his environment. The etymology of the word refers to the animating spirit of the individual.
Sigmund Freud defined the human psyche as consisting of the id, ego and superego. According to Freud, these three aspects of the psyche developed at different stages of maturity. The id is impulsive and demands immediate satisfaction, while the ego helps to mediate its demands with the real world. The super ego incorporates the values and norms of the world around the individual.
Carl Jung further refined the description of the psyche to include a collective unconsciousness. He saw the psyche as existing since birth. Jung taught that the psyche was not just the result of one's environment. He spoke of the self as the whole of the psyche, the persona as the part of the psyche that developed for personal convenience, and the shadow as carrying the things an individual was unwilling to admit about himself.
Cognitive psychology, which gained popularity in the 1950s and 1960s, after Freud and Jung, prefers the word mind to psyche. It teaches that the way to understand behavior is to understand the workings of the brain in processing information. Cognitive psychology remains the most popular school of thought as of 2014.