Posthypnotic suggestions

Post-hypnotic suggestion is the induction, under hypnosis, of a person into a behavior or thinking pattern that makes itself manifest after he has come out of the hypnotic state.

The phenomenon
Post-hypnotic suggestions are administered by a hypnotist and may optionally include a time scope. An altered sense of perception or behavioral pattern may be "programmed" into the person under hypnosis. Certain sequences of events may be set as triggers to enter or exit the post-hypnotic pattern. The behavior patterns resemble conditioned reflexes, though administered without classical behavior alteration techniques.

Examples
Any number, color, object, etc. may be induced to be ignored by the patient after full consciousness. A certain keyword starts the suggestion and a different word ends it. The patient will not know nor use the item to be ignored. He/she may state that the sea is colored red, if suggested to ignore the color blue. A count of eleven may be achieved if asked to count one's fingers if a number -say 5- is suggested to be ignored. Thus the patient counts 1-2-3-4-6-7-8-9-10-11

Different type of behavior patterns may be induced such as forcing the patient to recite a certain sentence whenever anyone says out loud the special keyword. The patient can be fully aware of the conditioned action but it is very difficult, if not impossible, to restrain from doing it. Sweating, loss of coordination and full lack of concentration plagues the patient until he/she performs the programmed action.

An object may be set to be perceived as invisible and it will be fully ignored and evaded during the period of suggestion. Experiments may be performed with a coffee mug, induced to be invisible. If the mug is put on top of a page with writing, the patient will only read the parts not covered by the mug. Even though the sentences may make no sense, nothing is seemingly wrong to the suscepted. It is difficult to suggest an object be invisible, yet stay tactile. Usually the object is completely ignored by all senses. Thus, the mug in the example will reportedly not exist, even when the patient is touching it.