That dreaming is a less sound species of sleep, appears from the familiar fact, which has probably been observed by every individual; viz. that the first sleep is much freer from it than the second. We retire to rest, fatigued by the exertions of the day, and sleep soundly for five or six hours: we wake, and then fall asleep again towards the morning, and dream the whole time of this second sleep.
— Abraham Rees: The Cyclopædia, Or, Universal Dictionary of Arts, Sciences, and Literature (1819)
Until the modern era, up to an hour or more of quiet wakefulness midway through the night interrupted the rest of most Western Europeans….Families rose from their beds to urinate, smoke tobacco, and even visit close neighbors. Remaining abed, many persons also made love, prayed, and, most important, reflected on the dreams that typically preceded waking from their “first sleep.” Not only were these visions unusually vivid, but their images would have intruded far less on conscious thought had sleepers not stirred until dawn. The historical implications of this traditional mode of repose are enormous, especially in light of the significance European households once attached to dreams for their explanatory and predictive powers. In addition to suggesting that consolidated sleep, such as we today experience, is unnatural, segmented slumber afforded the unconscious an expanded avenue to the waking world that has remained closed for most of the Industrial Age.
At first glance, it is tempting to view this pattern of broken sleep as a cultural relic rooted in early Christian experience….However…references to “first sleep” antedate Christianity’s early years of growth. Not only did such figures outside the church as Pausanias and Plutarch invoke the term in their writings, so, too, did early classical writers, including Livy in his history of Rome, Virgil in the Aeneid, both composed in the first century BC, and Homer in the Odyssey, written in either the late eighth or early seventh century BC! Conversely, in the twentieth century, some non-Western cultures with religious beliefs other than Christianity have long exhibited a segmented pattern of sleep remarkably similar to that of pre-industrial Europeans. Anthropologists have found villages of the Tiv, Chagga, and G/wi, for example, in Africa to be surprisingly alive after midnight with newly roused adults and children. Of the Tiv in central Nigeria, a study in 1969 recorded, “At night, they wake when they will and talk with anyone else awake in the hut.” The Tiv even employ the terms “first sleep” and “second sleep” as traditional intervals of time.
As suggested by recent experiments at the National Institute of Mental Health in Bethesda, Maryland, the explanation likely rests in the darkness that enveloped most pre-industrial families. In attempting to recreate conditions of “prehistoric” sleep, Dr. Thomas Wehr and his colleagues at NIMH found that human subjects, deprived at night of artificial light over a span of several weeks, eventually exhibited a pattern of broken slumber—astonishingly, one practically identical to that of pre-industrial households. Without artificial light for up to fourteen hours each night, Wehr’s subjects first lay awake in bed for two hours, slept for four, awakened again for two to three hours of quiet rest and reflection, then fell back asleep for four more hours before finally awakening for good. Significantly, the intervening period of “non-anxious wakefulness” possessed “an endocrinology all its own,” with visibly heightened levels of prolactin, a pituitary hormone best known for permitting chickens to brood contentedly atop eggs for long stretches of time. In fact, Wehr has likened this period of wakefulness to something approaching an altered state of consciousness not unlike meditation.
The…obvious commonality linking pre-industrial peoples to the subjects in Wehr’s experiments, shared too by non-Western cultures still experiencing broken slumber, was a severe shortage of artificial lighting, which in the early modern world fell hardest on the lower and middle classes. Interestingly, allusions to segmented sleep are most conspicuous in materials written or dictated by all but the wealthiest segments of society. References are sparse among the vast mounds of personal papers left by the upper classes. Their relative absence becomes increasingly evident by the late seventeenth century, when both artificial lighting and the vogue of “late hours” grew more prevalent among affluent households.
—A. Roger Ekirch: “Sleep We have Lost: Pre-Industrial Slumber in the British Isles” (2001)
French School, mid-18th century: An Allegory of Sleep