The modern expectation of one continuous, unbroken block of nighttime sleep may represent a genuinely recent historical development rather than humanity's natural default, according to research examining sleep patterns across centuries of written record.
The Historical Pattern Ekirch Documented
Historian Roger Ekirch's research on pre-industrial Western Europe found extensive documented evidence of a two-part sleep pattern, where individuals typically retired between 9 and 10pm, woke from a "first sleep" around midnight or later, remained awake for up to an hour or so, then settled into a "second sleep" continuing roughly until dawn. Ekirch found references to this first and second sleep pattern appearing consistently across medieval literature and classical works, including Virgil's Aeneid and Plutarch's writings, suggesting the pattern extended back well before the specific historical period his research initially focused on.
What the Waking Interval Was Actually Used For
The period of wakefulness between the two sleep segments, sometimes called "the watching," commonly involved activities including prayer, reading, or quiet conversation, representing a genuinely accepted and unremarkable part of the nighttime routine rather than a disruption to be minimized. This wakeful interval appears to have carried none of the anxiety modern insomnia sufferers often associate with middle-of-the-night waking, since the pattern itself was simply understood as normal.
Cross-Cultural Evidence Beyond Europe
Anthropological observations extending into the twentieth century documented segmented sleep patterns persisting in various indigenous societies across Nigeria, Central America and Brazil, communities that lacked artificial lighting and had skipped the industrialization Ekirch identifies as the driving force behind sleep consolidation. Researcher David Samson's study of a rural community in Madagascar similarly found a sleep pattern the research team described as strikingly similar to the first and second sleep pattern Ekirch documented in historical European sources.
Why Artificial Light Gets the Credit for the Shift
- Ekirch's research points to the growing pervasiveness of artificial illumination, first gas lighting and then electricity, as the primary driver reshaping the body's circadian clock toward consolidated sleep
- The Industrial Revolution's heightened emphasis on efficiency and productivity further reinforced this shift, with commentators at the time openly praising those who rose early rather than "enjoying that second sleep"
- By the late 1800s, segmented sleep had genuinely begun to arouse medical concern in the West, precisely as continuous sleep became the newly expected norm
- Parents during this transitional period were specifically instructed to train children toward early, consolidated waking before their sleep habits became fixed
A Genuinely Contested Historical Claim
It is worth noting this research remains an active scholarly debate rather than settled consensus, with historian Niall Boyce publishing a direct challenge to Ekirch's interpretation of the historical evidence, prompting Ekirch himself to publish a detailed rebuttal reaffirming his original conclusions using an expanded body of source material.
The takeaway: Historical evidence suggests segmented, two-part sleep may have been the predominant pattern across much of pre-industrial human history, with artificial lighting and industrialization driving the shift toward the consolidated single sleep block now considered standard, though this historical interpretation continues to generate genuine scholarly debate.