Why counting sheep stayed with us

Counting sheep is less a single ancient technique than a durable image: a repetitive task, a quiet landscape, and nothing important at stake.

The image is older than the habit. An early twelfth-century collection of tales, the Disciplina Clericalis of Petrus Alfonsi, already makes a joke of counting a flock, and Cervantes reworked it for Don Quixote in 1605, where Sancho Panza asks his master to keep count of a fisherman’s goats as they are ferried across a river, because if one is lost the story must end. The first known description of counting sheep as a way of falling asleep is more matter-of-fact: it appears in Harriet Martineau’s Illustrations of Political Economy in 1834, and by the 1860s the phrase was commonplace.

The appeal is easy to understand without making a medical claim for it. Each imagined sheep gives the mind a small job. The job repeats. If the count is lost, nothing has been lost with it.

Whether it works is another matter. In 2002 two researchers at the University of Oxford, Allison Harvey and Suzanna Payne, asked people with insomnia to try different strategies at bedtime. Those trained to picture an interesting, engaging scene in detail fell asleep sooner and reported fewer unwanted thoughts; those told simply to distract themselves did no better than people given no instruction at all. A bedtime task, it seems, has to hold the mind gently rather than merely occupy it.

Sleepy Wander brings that image back as a restrained reader board. Small illustrated sheep pass slowly; fences follow the prime numbers through eleven; then two fences close the field and the count begins again. You can watch or stop whenever the screen becomes unnecessary.