Editing Natural selection (section)

===Social and psychological theory===
{{Main|Evolutionary psychology}}
The social implications of the theory of evolution by natural selection also became the source of continuing controversy. [[Friedrich Engels]], a German [[Political philosophy|political philosopher]] and co-originator of the ideology of [[communism]], wrote in 1872 that "Darwin did not know what a bitter satire he wrote on mankind, and especially on his countrymen, when he showed that free competition, the struggle for existence, which the economists celebrate as the highest historical achievement, is the normal state of the ''animal kingdom''<!--author's emphasis-->."<ref>{{harvnb|Engels|1964}}</ref> Herbert Spencer and the eugenics advocate [[Francis Galton]]'s interpretation of natural selection as necessarily progressive, leading to supposed advances in intelligence and civilisation, became a justification for [[colonialism]], [[eugenics]], and [[social Darwinism]]. For example, in 1940, [[Konrad Lorenz]], in writings that he subsequently disowned, used the theory as a justification for policies of the [[Nazi]] state. He wrote "...&nbsp;selection for toughness, heroism, and social utility&nbsp;... must be accomplished by some human institution, if mankind, in default of selective factors, is not to be ruined by domestication-induced degeneracy. The racial idea as the basis of our state has already accomplished much in this respect."<ref>{{cite journal |last=Eisenberg |first=Leon |author-link=Leon Eisenberg |date=September 2005 |title=Which image for Lorenz? |journal=[[American Journal of Psychiatry]] |type=Letter to the editor |volume=162 |issue=9 |page=1760 |doi=10.1176/appi.ajp.162.9.1760 |pmid=16135651}} Eisenberg quoting translation of ''Durch Domestikation verursachte Störungen arteigenen Verhaltens'' (1940, p. 2) by [[Konrad Lorenz]].</ref> Others have developed ideas that human societies and culture [[Sociocultural evolution|evolve]] by mechanisms analogous to those that apply to evolution of species.<ref>{{harvnb|Wilson|2002}}</ref>

More recently, work among anthropologists and psychologists has led to the development of [[sociobiology]] and later of evolutionary psychology, a field that attempts to explain features of [[Psychology|human psychology]] in terms of adaptation to the ancestral environment. The most prominent example of evolutionary psychology, notably advanced in the early work of [[Noam Chomsky]] and later by [[Steven Pinker]], is the hypothesis that the human brain has adapted to [[language acquisition|acquire]] the [[grammar|grammatical]] rules of [[natural language]].<ref name="Pinker">{{harvnb|Pinker|1995}}</ref> Other aspects of human behaviour and social structures, from specific cultural norms such as [[Westermarck effect#Westermarck effect|incest avoidance]] to broader patterns such as [[gender role]]s, have been hypothesised to have similar origins as adaptations to the early environment in which modern humans evolved. By analogy to the action of natural selection on genes, the concept of [[meme]]s—"units of cultural transmission," or culture's equivalents of genes undergoing selection and recombination—has arisen, first described in this form by [[Richard Dawkins]] in 1976<ref>{{harvnb|Dawkins|1976|p=192}}</ref> and subsequently expanded upon by philosophers such as [[Daniel Dennett]] as explanations for complex cultural activities, including human [[consciousness]].<ref>{{harvnb|Dennett|1991}}</ref>