Editing Evolutionary psychology (section)

====Emotion and motivation====
{{Main|Evolution of emotion}}
Motivations direct and energize behavior, while emotions provide the affective component to motivation, positive or negative.<ref name=Gaulin-6>Gaulin and McBurney 2003 pp. 121–42.</ref> In the early 1970s, [[Paul Ekman]] and colleagues began a line of research which suggests that many emotions are universal.<ref name=Gaulin-6/> He found evidence that humans share at least five basic emotions: fear, sadness, happiness, anger, and disgust.<ref name=Gaulin-6/> Social emotions evidently evolved to motivate social behaviors that were adaptive in the environment of evolutionary adaptedness.<ref name=Gaulin-6/> For example, spite seems to work against the individual but it can establish an individual's reputation as someone to be feared.<ref name=Gaulin-6/> Shame and pride can motivate behaviors that help one maintain one's standing in a community, and self-esteem is one's estimate of one's status.<ref name=moralanimal/><ref name=Gaulin-6/>
Motivation has a neurobiological basis in the [[reward system]] of the brain. Recently, it has been suggested that reward systems may evolve in such a way that there may be an [[inherent]] or unavoidable [[trade-off]] in the motivational system for activities of short versus long duration.<ref>{{cite journal | last1 = Belke | first1 = T. W. | last2 = Garland | first2 = T. Jr. | year = 2007 | title = A brief opportunity to run does not function as a reinforcer for mice selected for high daily wheel-running rates | journal = [[Journal of the Experimental Analysis of Behavior]] | volume = 88 | issue = 2| pages = 199–213 | doi=10.1901/jeab.2007.62-06| pmc = 1986434 | pmid=17970415}}</ref>