Another example of the force of suggestion, whether unconscious or openly exercised by speech, is given us in the matter of sleep. Among adults the act of going to bed serves as a powerful suggestion to induce sleep. Seldom do we seek rest so tired physically that we drop off to sleep from the irresistible force of sheer exhaustion. Yet as soon as the healthy man whose mind is at peace, whose nerves are not on edge, finds himself in bed, his eyes close almost with the force of a hypnotic suggestion, and he drops off to sleep. With some of us the suggestion is only powerful in our own bed, that on which it has acted on unnumbered nights. We cannot, as we say, sleep in a strange bed. It is suggestion, not direct will power, that acts. No one can absolutely will himself to sleep. In insomnia it is the attempt to replace the unconscious auto-suggestion by a conscious voluntary effort of will that causes the difficulty. A thousand times in the night we resolve that now we will sleep. If we could but cease to make these fruitless efforts, sleep might come of itself and the suggestion or habit be re-established.
In little children the suggestion of sleep, provoked by being placed in bed, sometimes acts very irregularly. Often it may succeed for a week or two, and then some untoward happening breaks the habit, and night after night, for a long time, sleep is refused. The wakeful child put to bed, resents the process, and cries and sobs miserably, to the infinite distress of his mother. It then becomes just as likely that the child will connect his bed in his mind, not with rest and sleep, but with sobbing and crying on his part, and mingled entreaties and scoldings from his nurse or mother. An important part in this perversion of the suggestion is played by the attitude of the person who puts the child to bed. Often the nurse is uniformly successful, while the mother, who is perhaps more distressed by the sobbing of the child, as consistently fails, because she has been unable to hide her apprehension from him, and has conveyed to his mind a sense of his own power.