Editing Psychological egoism (section)

==Contributions to modern psychology==

===Psychoanalysis===
Whether or not Sigmund Freud was a psychological egoist, his concept of the [[pleasure principle (psychology)|pleasure principle]] borrowed much from psychological egoism and psychological hedonism in particular.<ref>Wallwork, E. (1991). p. 110</ref> The pleasure principle rules the behavior of the [[Id, ego and super-ego#Id|Id]] which is an unconscious force driving humans to release tension from unfulfilled desires. When Freud introduced [[Thanatos#In psychology and medicine|Thanatos]] and its opposing force, [[Eros (concept)#Sigmund Freud|Eros]], the pleasure principle emanating from psychological hedonism became aligned with the Eros, which drives a person to satiate sexual and reproductive desires.<ref>Wallwork, E. (1991). p. 125</ref>  Alternatively, Thanatos seeks the cessation of pain through death and the end of the pursuit of pleasure: thus, hedonism rules Thanatos, but it centers on the complete avoidance of pain rather than psychological hedonist function which pursues pleasure and avoids pain. Therefore, Freud believed in qualitatively different hedonisms where the total avoidance of pain hedonism and the achievement of the greatest net pleasure hedonism are separate and associated with distinct functions and drives of the human psyche.<ref>Wallwork, E. (1991). p. 132-33</ref> Although Eros and Thanatos are ruled by qualitatively different types of hedonism, Eros remains under the rule of Jeremy Bentham's [[Quantity|quantitative]] psychological hedonism because Eros seeks the greatest net pleasure.

===Behaviorism===
Traditional [[behaviorism]] dictates all human behavior is explained by [[Classical Conditioning|classical conditioning]] and [[operant conditioning]].  Operant conditioning works through [[reinforcement]] and [[Punishment (psychology)|punishment]] which adds or removes pleasure and pain to manipulate behavior.  Using pleasure and pain to control behavior means behaviorists assumed the principles of psychological hedonism could be applied to predicting human behavior.  For example, [[Edward Thorndike#Thorndike's theory of learning|Thorndike's law of effect]] states that behaviors associated with pleasantness will be learned and those associated with pain will be extinguished.<ref>Young, P. T. (1936). p. 332</ref> Often, behaviorist experiments using humans and animals are built around the assumption that subjects will pursue pleasure and avoid pain.<ref>Young, P. T. (1936) and Mehiel, R. (1997).</ref> Although psychological hedonism is incorporated into the fundamental principles and experimental designs of behaviorism, behaviorism itself explains and interprets only observable behavior and therefore does not theorize about the ultimate cause of human behavior. Thus, behaviorism uses but does not strictly support psychological hedonism over other understandings of the ultimate drive of human behavior.