There are many ways of sleeping and few cultures sleep in eight-hour consolidated blocks like we do. Until the industrial era, many Western Europeans divided the night into “the first sleep” and the “second sleep.” They’d go to bed soon after dark, sleep for four hours then wake for an hour or two during which they’d write, pray, smoke, have sex or even visit neighbors. In fact, there’s some evidence to suggest that this sleep pattern may be the one most in tune with our inherent circadian rhythms.