In science, psychology is systematic study of human and animal behavior, with particular focus on internal processes and motives. [1] The thermodynamic study of psychology is called “psychodynamics”, a field generally developed, beginning in the late 1870s, by Austrian psychiatrist Sigmund Freud. [2]

References
1. (a) Clark, John O.E. (2004). The Essential Dictionary of Science. New York: Barnes & Noble Books.
(b) Eysenck, Michael W. (2004). Psychology: An International Perspective, (pg. 3). Taylor & Francis.
2. Hall, Calvin, S. (1954). A Primer in Freudian Psychology. Meridian Book.