Editing Sleep (section)

===Anthropology===
[[File:Pieter Bruegel d. Ä. 037.jpg|thumb|''[[The Land of Cockaigne (Bruegel)|The Land of Cockaigne]]'' by [[Pieter Bruegel the Elder]], 1567]]

Research suggests that sleep patterns vary significantly across cultures.<ref name=Worthman>{{cite book | vauthors = Worthman CM, Melby MK | veditors = Carskadon MA |title=Adolescent Sleep Patterns: Biological, Social, and Psychological Influences |chapter=6. Toward a comparative developmental ecology of human sleep |chapter-url=https://www.cambridge.org/core/books/abs/adolescent-sleep-patterns/toward-a-comparative-developmental-ecology-of-human-sleep/96AAC229B2DE0A1E5346631BEFAEE526 |publisher=Cambridge University Press |date=2002 |pages=69–117 |doi=10.1017/CBO9780511499999.009 |isbn=978-0521642910 }}</ref><ref name="Jeon">{{cite journal | vauthors = Jeon M, Dimitriou D, Halstead EJ | title = A Systematic Review on Cross-Cultural Comparative Studies of Sleep in Young Populations: The Roles of Cultural Factors | journal = International Journal of Environmental Research and Public Health | volume = 18 | issue = 4 | pages = 2005 | date = February 2021 | pmid = 33669583 | pmc = 7922907 | doi = 10.3390/ijerph18042005 | doi-access = free }}</ref><ref name="Samson">{{cite journal | vauthors = Samson DR |title=The Human Sleep Paradox: The Unexpected Sleeping Habits of Homo sapiens |journal=Annual Review of Anthropology |date=21 October 2021 |volume=50 |issue=1 |pages=259–274 |doi=10.1146/annurev-anthro-010220-075523 |s2cid=237845665 |url=https://doi.org/10.1146/annurev-anthro-010220-075523 |access-date=2 June 2022 |language=en |issn=0084-6570|url-access=subscription }}</ref> The most striking differences are observed between societies that have plentiful sources of artificial light and ones that do not. The primary difference appears to be that pre-light cultures have more broken-up sleep patterns. For example, people without artificial light might go to sleep far sooner after the sun sets, but then wake up several times throughout the night, punctuating their sleep with periods of wakefulness, perhaps lasting several hours.<ref name=Worthman/> During [[pre-industrial society|pre-industrial]] [[Europe]], [[Biphasic and polyphasic sleep|biphasic (bimodal) sleeping]] was considered the norm. Sleep onset was determined not by a set bedtime, but by whether there were things to do.<ref>{{cite web |title=Humans Used to Sleep in Two Shifts, And Maybe We Should Do It Again |date=4 April 2018 |access-date=7 February 2022 | vauthors = Jackson M, Banks S |website=Science Alert |url=https://www.sciencealert.com/humans-used-to-sleep-in-two-shifts-maybe-we-should-again}}</ref>

The boundaries between sleeping and waking are blurred in these societies. Some observers believe that nighttime sleep in these societies is most often split into two main periods, the first characterized primarily by deep sleep and the second by REM sleep.<ref name=Worthman/>

Some societies display a fragmented sleep pattern in which people sleep at all times of the day and night for shorter periods. In many [[nomad]]ic or [[hunter-gatherer]] societies, people sleep on and off throughout the day or night depending on what is happening. Plentiful [[artificial light]] has been available in the industrialized West since at least the mid-19th century, and sleep patterns have changed significantly everywhere that lighting has been introduced. In general, people sleep in a more concentrated burst through the night, going to sleep much later, although this is not always the case.<ref name=Worthman/>

Historian [[A. Roger Ekirch]] thinks that the traditional pattern of "[[segmented sleep]]," as it is called, began to disappear among the urban upper class in Europe in the late 17th century and the change spread over the next 200 years; by the 1920s "the idea of a first and second sleep had receded entirely from our social consciousness."<ref>{{cite journal | vauthors = Ekirch AR | title = Sleep we have lost: pre-industrial slumber in the British Isles | journal = The American Historical Review | volume = 106 | issue = 2 | pages = 343–86 | year = 2001 | pmid = 18680884 | doi = 10.2307/2651611 | jstor = 2651611 }}</ref><ref name=bbc>{{cite news| vauthors = Hegarty S |title=The myth of the eight-hour sleep|url=https://www.bbc.co.uk/news/magazine-16964783|access-date=22 February 2012|newspaper=BBC News|date=22 February 2012|archive-url=https://web.archive.org/web/20120222172348/https://www.bbc.co.uk/news/magazine-16964783|archive-date=22 February 2012|url-status=live}}</ref> Ekirch attributes the change to increases in "street lighting, domestic lighting and a surge in coffee houses," which slowly made nighttime a legitimate time for activity, decreasing the time available for rest.<ref name=bbc/> Today in most societies people sleep during the night, but in very hot climates they may sleep during the day.<ref>[[Ellsworth Huntington|Huntington, Ellsworth]] (1915) [https://archive.org/details/civilizationand01huntgoog ''Civilization and Climate''] {{Webarchive|url=https://web.archive.org/web/20160817211746/https://archive.org/details/civilizationand01huntgoog |date=17 August 2016 }}. Yale University Press. p. 126</ref> During [[Ramadan]], many Muslims sleep during the day rather than at night.<ref>{{cite book |title=The American Muslim Teenager's Handbook | vauthors = Hafiz D, Hafiz I, Hafiz Y |year=2009 | publisher = Simon & Schuster Children's |isbn=978-1416986997 |url-access=registration |url=https://archive.org/details/muslimteenagersh0000hafi }}</ref>

In some societies, people sleep with at least one other person (sometimes many) or with animals. In other cultures, people rarely sleep with anyone except for an intimate partner. In almost all societies, sleeping partners are strongly regulated by social standards. For example, a person might only sleep with the [[immediate family]], the [[extended family]], a spouse or romantic partner, children, children of a certain age, children of a specific gender, peers of a certain gender, friends, peers of equal social rank, or with no one at all. Sleep may be an actively social time, depending on the sleep groupings, with no constraints on noise or activity.<ref name=Worthman/>

People sleep in a variety of locations. Some sleep directly on the ground; others on a skin or blanket; others sleep on platforms or [[bed]]s. Some sleep with blankets, some with pillows, some with simple headrests, some with no head support. These choices are shaped by a variety of factors, such as climate, protection from predators, housing type, technology, personal preference, and the incidence of pests.<ref name="Worthman"/>