Editing Origin of language (section)

=== Self-domesticated ape theory ===
According to a study investigating the song differences between [[white-rumped munia]]s and its domesticated counterpart ([[Society finch|Bengalese finch]]), the wild munias use a highly stereotyped song sequence, whereas the domesticated ones sing a highly unconstrained song. In wild finches, song syntax is subject to female preference—[[sexual selection]]—and remains relatively fixed. However, in the Bengalese finch, natural selection is replaced by breeding, in this case for colorful plumage, and thus, decoupled from selective pressures, stereotyped song syntax is allowed to drift. It is replaced, supposedly within 1000 generations, by a variable and learned sequence. Wild finches, moreover, are thought incapable of learning song sequences from other finches.<ref name="Soma2009">{{Cite journal |last1=Soma |first1=M. |last2=Hiraiwa-Hasegawa |first2=M. |last3=Okanoya |first3=K. |year=2009 |title=Early ontogenetic effects on song quality in the Bengalese finch (''Lonchura striata var. domestica''): laying order, sibling competition and song syntax |url=https://ir.soken.ac.jp/?action=repository_uri&item_id=3818 |journal=Behavioral Ecology and Sociobiology |volume=63 |issue=3 |pages=363–370 |doi=10.1007/s00265-008-0670-9 |bibcode=2009BEcoS..63..363S |s2cid=23137306}}</ref> In the field of [[bird vocalization]], brains capable of producing only an innate song have very simple neural pathways: the primary forebrain motor centre, called the robust nucleus of [[arcopallium]], connects to midbrain vocal outputs, which in turn project to brainstem motor nuclei. By contrast, in brains capable of learning songs, the arcopallium receives input from numerous additional forebrain regions, including those involved in learning and social experience. Control over song generation has become less constrained, more distributed, and more flexible.<ref name="Soma2009" />

One way to think about human evolution is that humans are [[Self-domestication#In humans|self-domesticated apes]]. Just as domestication relaxed selection for stereotypic songs in the finches—mate choice was supplanted by choices made by the aesthetic sensibilities of bird breeders and their customers—so might human cultural domestication have relaxed selection on many of their primate behavioural traits, allowing old pathways to degenerate and reconfigure. Given the highly indeterminate way that mammalian brains develop—they basically construct themselves "bottom up", with one set of neuronal interactions preparing for the next round of interactions—degraded pathways would tend to seek out and find new opportunities for synaptic hookups. Such inherited de-differentiations of brain pathways might have contributed to the functional complexity that characterises human language. And, as exemplified by the finches, such de-differentiations can occur in very rapid time-frames.<ref>{{Cite journal |last1=Ritchie |first1=Graham |last2=Kirby |first2=Simon |year=2005 |title=Selection, domestication, and the emergence of learned communication systems |url=http://homepages.inf.ed.ac.uk/s0237680/pubs/ritchie_05_selection.pdf |url-status=dead |journal=Second International Symposium on the Emergence and Evolution of Linguistic Communication |archive-url=https://web.archive.org/web/20120121153322/http://homepages.inf.ed.ac.uk/s0237680/pubs/ritchie_05_selection.pdf |archive-date=21 January 2012}}</ref>