The debate on whether hypnosis is a state or a non-state is known as the 'altered state debate.' People who believe that hypnosis does not involve an altered state of consciousness argue that the effects of hypnosis and suggestions can be achieved without a hypnotic induction (Whalley, 2009). One researcher (Spanos, 1986) believes that suggestions, including analgesia suggestions and amnesia suggestions, have a socio-cognitive link. Spanos believes that people who undergo hypnosis are able to convince themselves to believe a certain way and this occurs cognitively and not due to an altered state of consciousness.
An altered state of consciousness (ASC) is defined as, "any of various states of awareness (as dreaming sleep, a drug-induced hallucinogenic state, or a trance) that deviate from and are usually clearly demarcated from ordinary waking consciousness" (Meriam-Webster). An altered state is often compared to a baseline state which is a state where "the psychological sense of the self is at the center of one's perception" (Whalley, 2009).
A scientific aspect of this debate about where hypnosis comes from involves looking at brain functioning and brain images. When studying the brain, researchers are presented with an important question: How much different from the baseline state would hypnosis have to be in order to be classified as an altered state of consciousness?
Various methods are being used to determine how to measure hypnosis. Neuro-imaging is being used including PET and fMRI scans. These tests allow one to see activity in the brain during hypnosis and without hypnosis. Another method of measurement includes behavioral studies. Studies attempt to compare the behavior of hypnotized and non-hypnotized individuals (Whalley, 2009).
The debate on whether hypnosis is an altered state of consciousness continues to be argued. There are multiple studies that back up both sides of the argument. At this point in time, there is no clear answer. With time, as more behavioral studies are conducted and as researchers learn more about the human brain and its functioning, we will learn exactly how hypnosis occurs in the mind.