I imagine that most of y'all who have studied sociology already know that prior to industrial capitalism the majority of human civilizations favored segmented/biphastic sleep schedules, but I learned this information freshly today and it feels like insanity. So much of what I believe about the human condition is arbitrarily constructed.
It is clear that biphasic sleep was not unique to Western households. Instead, it occurred well beyond the bounds of Europe and North America in other cultures and continents, including the Middle East, Africa, South Asia, Southeast Asia, Australia, and Latin America, thereby heightening the likelihood that throughout the preindustrial world this form of sleep was not at all uncommon, including in equatorial cultures.4 The French priest André Thevet, on traveling to Rio de Janeiro, Brazil in 1555, reported that the Tupinamba Indians ate whenever they had an appetite, “even at night after their first sleep they get up to eat and then return to sleep.”5 In the early 19th century, residents of Muscat, the capital of Oman, were said to retire early, lying “down before 10 o'clock,” so that “before midnight their first sleep” was “usually over.”6
More recently, ethnographic evidence from the late 19th century to the latter half of the 20th century indicates that numerous non-Western cultures not exposed to artificial lighting still experienced “first” and “second” sleep, from Surinamese Maroons on the northeastern coast of South America7 to the As-ante and Fante on the West African coast, for whom the phrase in their native Tshi language “woadá ayi d. fā” signifies “they lie in the first sleep,” whereas “wayi (or wada) d. biakō” reads “he has slept the first part of the night.”8
