Hypnosis is a psychological state whose existence and effects are strongly debated. Some believe that it is a state under which the subject's mind becomes so suggestible that the hypnotist, the one who induces the state, can command behavior that the subject would not choose to perform in a conscious state (even behavior to be performed after the subject has left the hypnotic state, through post-hypnotic suggestion,) or even behavior the subject would be incapable of in a conscious state, such as not feeling pain, manifesting skin blisters as if the subject had been burned, or recalling things the subject's conscious memory does not retain. However, there is strong dispute and skepticism about what behavior and effects hypnosis can induce; some believe that the state does not actually exist, and that all effects of 'hypnotism' that have been observed are in actuality a combination of subjects' expectations (based on their beliefs of hypnotism's effects) and their desire to please the hypnotist (see Hawthorne Effect).

Not surprisingly, given the disagreements described above, there is also wide disagreement about whether it has uses in fields such as mental health, medicine and law enforcement. Some promote hypnotism as a powerful tool for therapists to treat patients, claiming that it can bring up to consciousness painful repressed memories. Some even claim that it can retrieve repressed memories of alien abductions, Satanic ritual abuse, or memories from past lives. Others point to this very fact, that subjects under hypnosis can develop and come to wholly believe in "memories" that are implausible (or even proven false by existing evidence), as proof that hypnosis is, if it even exists, a tool proved too unreliable to be safely used in any important undertaking.


The act of inducing a hypnotic state is referred to as an induction procedure. There is no current consensus on what the requirements are for an induction procedure to be effective; while some practitioners use simple calming verbal techniques, others use complex triggers, including mechanical devices.

Many experienced hypnotists claim that they can hypnotize almost anyone. They also claim it is a myth that people with strong will power cannot be hypnotized, as they claim these generally make the best participants. This is based on the idea that those who are most intelligent are also the most creative and as such they will make strong associations with the structure of language used by the hypnotist and by the visual or auditory representations inside of their mind. On the other hand, there is a common claim that no one can really be hypnotized against his or her will (Liébault, Le sommeil provoqué (Paris, 1889)). The counter-claim given by many hypnotists is that while you cannot make someone do anything against their will, you can change what it is that they wish to do.

Many religious and cultural rituals contain many similarities with techniques used for hypnotic induction and induce similar states in their participants.


Research into the state of hypnosis has been widely covered with varying results.

Nevertheless, some modern research seems to suggest that hypnosis has a genuine effect on brain functioning. For example, one controlled scientific experiment postulates that hypnosis may change conscious experience in a way not possible when people are not 'hypnotized', at least in "highly hypnotizable" people. In this experiment, color perception was changed by hypnosis in "highly hypnotizable" people as determined by positron emission tomography (PET) scans (Kosslyn et al., 2000). (This research does not compare the effects of hypnosis on less hypnotizable people and could therefore show little causal effect due to the lack of a control group.) Another research example, employing event-related fMRI and EEG coherence measures, compared certain specific neural activity "during Stroop task performance between participants of low and high hypnotic susceptibility, at baseline and after hypnotic induction". According to its authors, "the fMRI data revealed that conflict-related ACC activity interacted with hypnosis and hypnotic susceptibility, in that highly susceptible participants displayed increased conflict-related neural activity in the hypnosis condition compared to baseline, as well as with respect to subjects with low susceptibility." (Egner et al., 2005) The subject is still a matter of current research and scientific debate.

Other claims that hypnosis has been used with variable success for hundreds of applications, including entertainment, analgesia and psychoanalysis are widespread and well-documented.

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