Editing Psychology (section)

=== Motivation ===
{{Main|Motivation}}
Some psychologists study motivation or the subject of why people or lower animals initiate a behavior at a particular time. It also involves the study of why humans and lower animals continue or terminate a behavior. Psychologists such as William James initially used the term ''motivation'' to refer to intention, in a sense similar to the concept of ''[[Will (philosophy)|will]]'' in European philosophy. With the steady rise of Darwinian and Freudian thinking, instinct also came to be seen as a primary source of motivation.<ref name=ForgasEtAl>Forgas, Williams, & Laham, "Social Motivation: Introduction and Overview", in Forgas, Williams, & Laham, ''Social Motivation'' (2005).</ref> According to [[drive theory]], the forces of instinct combine into a single source of energy which exerts a constant influence. Psychoanalysis, like biology, regarded these forces as demands originating in the nervous system. Psychoanalysts believed that these forces, especially the sexual instincts, could become entangled and transmuted within the psyche. Classical psychoanalysis conceives of a struggle between the pleasure principle and the [[reality principle]], roughly corresponding to id and ego. Later, in ''[[Beyond the Pleasure Principle]]'', Freud introduced the concept of the ''[[death drive]]'', a compulsion towards aggression, destruction, and [[Repetition compulsion|psychic repetition of traumatic events]].<ref>Weiner, ''Human Motivation'' (2013), Chapter 2, "The Psychoanalytic Theory of Motivation" (pp. 9–84).</ref> Meanwhile, behaviorist researchers used simple dichotomous models (pleasure/pain, reward/punishment) and well-established principles such as the idea that a thirsty creature will take pleasure in drinking.<ref name=ForgasEtAl /><ref name=GodsilEtAl>Bill P. Godsil, Matthew R. Tinsley, & Michael S. Fanselow, "Motivation", in Weiner (ed.), ''Handbook of Psychology'' (2003), Volume 4: ''Experimental Psychology''.</ref> [[Clark Hull]] formalized the latter idea with his [[Drive reduction theory (learning theory)|drive reduction]] model.<ref>Weiner, ''Human Motivation'' (2013), Chapter 3, "Drive Theory" (pp. 85–138).</ref>

Hunger, thirst, fear, sexual desire, and thermoregulation constitute fundamental motivations in animals.<ref name=GodsilEtAl /> Humans seem to exhibit a more complex set of motivations—though theoretically these could be explained as resulting from desires for belonging, positive self-image, self-consistency, truth, love, and control.<ref>[[E. Tory Higgins]], ''Beyond Pleasure and Pain: How Motivation Works''; Oxford University Press, 2012; {{ISBN|978-0-19-976582-9}}{{page needed|date=February 2019}}</ref><ref>Shah & Gardner, ''Handbook of Motivation Science'' (2008), entire volume.{{page needed|date=February 2019}}</ref>

Motivation can be modulated or manipulated in many different ways. Researchers have found that [[eating]], for example, depends not only on the organism's fundamental need for [[homeostasis]]—an important factor causing the experience of hunger—but also on circadian rhythms, food availability, food palatability, and cost.<ref name=GodsilEtAl /> Abstract motivations are also malleable, as evidenced by such phenomena as ''goal contagion'': the adoption of goals, sometimes unconsciously, based on inferences about the goals of others.<ref>Hank Aarts, Ap Dijksterhuis, & Giel Dik, "Goal Contagion: Inferring goals from others' actions—and what it leads to", in Shah & Gardner, ''Handbook of Motivation Science'' (2008). "In short, then, the studies presented above indicate that humans are keen to act on the goals of other social beings that are implied in behavioral scenarios or scripts." Also see: {{cite journal | last1 = Aarts | last2 = Hassin | last3 = Gollwitzer | title = Goal Contagion: Perceiving is for Pursuing | journal = Journal of Personality and Social Psychology | volume = 87 | issue = 1| year = 2004 | doi=10.1037/0022-3514.87.1.23 | pages=23–37 | pmid=15250790| citeseerx = 10.1.1.312.5507 }}</ref> Vohs and [[Roy Baumeister|Baumeister]] suggest that contrary to the need-desire-fulfillment cycle of animal instincts, human motivations sometimes obey a "getting begets wanting" rule: the more you get a reward such as self-esteem, love, drugs, or money, the more you want it. They suggest that this principle can even apply to food, drink, sex, and sleep.<ref>Kathleen D. Vohs & [[Roy F. Baumeister]], "Can Satisfaction Reinforce Wanting? A new theory about long-term changes in strength of motivation", in Shah & Gardner, ''Handbook of Motivation Science'' (2008).</ref>