Sleep induction
Sleep induction, the deliberate effort to bring on sleep by various techniques or medicinal means, is practiced to lengthen periods of sleep, increase the effectiveness of sleep, and to reduce or prevent insomnia.
Alcohol
An alcoholic drink or nightcap is a long-standing folk method which will induce sleep, as alcohol is a sedative. However, when the alcohol blood level subsides, there is a rebound effect: the person becomes more alert and so tends to wake up too soon. Also, if they continue to sleep, REM sleep is promoted, and this may cause vivid nightmares which can reduce the quality of the sleep.
Guided imagery
To relax and encourage sleep, a meditation in the form of guided imagery may be used. The stereotypical method is by counting sheep, imagining sheep jumping over a fence, while counting them.
In most depictions of the activity, the person envisions an endless series of identical white sheep jumping over a fence, while counting the number that do so. The idea, presumably, is to induce boredom while occupying the mind with something simple, repetitive, and rhythmic, all of which are known to help humans sleep. It may also simulate REM sleep, tiring people's eyes.
