There are two ways by which hypnosis is performed: (1) hetero-hypnosis, wherein a hypnotist induces a state of being in trance and being open to suggestions; and (2) auto-hypnosis, wherein the state is self-induced.
The results are the same. Any suggestion that is carried out a period of time after hypnosis, is known as post-hypnotic suggestion.
Believe it or not, we experience being hypnotized everyday following the definition of hypnosis as being in a trance-like state, or intensely focusing on a particular activity/subject thus tuning out almost everything else internally and otherwise.
Ever been so engrossed with a movie or a book that you did not immediately notice someone calling you already at the top of his voice? Reading, writing, closely listening to a record are examples of activities that can put us in a light trance, and altering our attention such that we can become extremely attentive to these, that we unconsciously shut off outside subjects vying for our attention.
Furthermore, we sometimes become so affected by the imaginary world of a daydream or a chapter of a book that our emotions take over. We cry over an affecting song, feel fear as the villain gets near the heros hiding place, or even scream over a particularly frightening scene.
This kind of phenomenon, referred to as self-hypnosis, is so common and so human a trait that Milton Erickson, a hypnotism expert in the 20th century, concluded that people hypnotize themselves on a daily basis.
