3. How reliable are things remembered under hypnosis?

This has often arisen as both a legal issue (as in the reliability of testimony obtained during or after hypnotherapy) and also a social issue(regarding the use of hypnotherapy to establish evidence of early child abuse, for example).

It is entirely true that subjects under hypnosis frequently recall past forgotten events (or 'repressed' memories in the jargon of psychoanalysis indicating an active role of the individual in forgetting as a defense mechanism).

It is also true that people under hypnosis often 'remember' things quite vividly that never actually happened, but which have great personal significance nonetheless. Psychiatrist William Sargent was one of the first to document the therapeutic benefit of emotionally charged experience, or abreaction, of fantasized life events.

This is one of defining characteristics of deep trance hypnosis in fact, the intensity of fantasies as well as memories, and the inability to distinguish the two. This characteristic of trance is what makes is possible to usehypnotherapy to alter personal history in order to reduce the traumaticeffects of past events on an individual's functioning. Not simply a relivingor 'catharsis' of the trauma, but a sometimes a lasting modification of theinterpretation of the memory can and does occur in many cases.

This apparent violability and fallibility of human memory is frequentlydownplayed in discussions of hypnotic recall because of the already difficulttime that legitimate victims of abuse have in proving what happened to them.It's not the intention here to make life more difficult for abuse victims,only to point out that hypnosis doesn't neccessarily solve their problem ofdigging out facts from old memories as neatly as we'd like it to.

The illusion of unusual veracity of hypnotic recall appears to come from atleast two main sources:

1. Older models of human memory as a simple recording and playback mechanismwhich preserved extreme details of everything perceived, and which could beplayed back in an enhanced way under certain conditions, like hypnosis.
2. The vividness and subjective meaningfulness often attributed toexperiences under hypnosis partly as a result of the unique characteristics ofhypnotic imagery.

Recognizing the potential difficulties arising from what some call 'falsememory syndrome,' several states in the U.S. now confine legal testimony tothat obtained prior to any systematic hypnotic treatment.

In 1985, a committee commissioned by the American Medical Associationcautioned against the systematic use of hypnosis for recollection for both itsunreliability (the possibility for example of 'confabulation,' the creation ofstories out of whole cloth to help fill in missing memories) and its potentialto create vivid false memories with an artificially induced sense ofcertainty.

In addition to the previously provided references for hypermnesia, here aresome more specifically devoted to the limitations of hypnotic recall:

• D. Spiegel et al, 1989, "Hypnotic alteration of somatosensory perception,"American Journal of Psychiatry.
• Loftus and Loftus, "On the permanence of stored information in the humanbrain," American Psychologis"t, 35(5):409-420 (May,1980), criticallyevaluates the data gathered by neurologist Wilder Penfield who had oncebelieved he had discovered during the probing of the brains of epilepticpatients a 'sequential record of consciousness' similar to the oldtape-recorder model of human memory.

No one yet knows exactly how human memory works in all its details, but theview of hypnotic recall as potentially highly fallible is also supported byclinical experience and experimental data.

Milton Erickson called the vivid experiences under hypnosis 'vivification,'and describes how a vivified image is experienced, regardless of whetherremembered or constructed:

"... They are subjectively experienced as external events rather than asinternal processes, with a consequent endowment of them as realityexperiences."

"... They identified it with actual past experiences and thus endowed it witha subjective validity."

"... They 'created a reality' that permitted a responsive functioning inaccord with the demands of the experiment."

Are there identified physiological correlates for such vivid recollections orre-creations of past events? One controversial researcher, Michael Persinger,has written hundreds of articles on the subject of neurophysiologicalcorrelates of extraordinary experiences of all kinds. He has reportedlyreproduced something like ecstatic mystical states with the help ofelectromagnetic stimulation of the cortical temporal lobes of human subjects,and facilitated vivid imagery akin to UFO abduction experiences. He is notalone in the observation of what is sometimes known as 'clinical mysticism,'which is seen in some forms of temporal lobe epilepsy and in mechanicalstimulation of areas of the temporal lobes, but he is somewhat unique in hisrepeatedly published insistence that all or virtually all unexplainedpheonomena and seemingly false memories can be traced to electromagneticeffects on the brain. For an article particularly pertinent to the issue ofhypnotic recall, see:

• Persinger MA. Neuropsychological profiles of adults who report "suddenremembering" of early childhood memories: implications for claims of sex abuseand alien visitation/abduction experiences. Perceptual & Motor Skills.75(1):259-66, 1992 Aug.
• "Six adults, who had recently experienced sudden recall of preschool memoriesof sex abuse or alien abduction/visitation, were given completeneuropsychological assessments. All experiences "emerged" when hypnosis wasutilized within a context of sex abuse or New Age religion and were followedby reduction in anxiety. As a group, these subjects displayed significant (Tgreater than 70) elevations of childhood imaginings, complex partialepileptic-like signs, and suggestibility. Neuropsychological data indicatedright frontotemporal anomalies and reduced access to the right parietal lobe.MMPI profiles were normal. The results support the hypothesis that enhancedimagery due to temporal lobe lability within specific contexts can facilitatethe creation of memories; they are strengthened further if there is alsoreduction in anxiety." (Taken from an on-line abstract).

If there is anything to this 'temporal lobe lability' hypothesis, it seemswell worthwhile investigating its relationship to hypnotic suggestibility, andthe hypothetical 'Fantasy Prone Personality' of Barber and Wilson.

As for recall under hypnosis, the experimental observation seems to be thatthe subject is uniquely motivated to remember details, but also uniquelycapable of making up details and experiencing them as if they were remembered.

In Lynn and Rhue's 1991 Theories of Hypnosis, Robert Nadon et al.discuss a representative example of experiments in eyewitness recall with theaid of hypnosis. Subjects were shown a videotape of a mock armed robbery.They were then asked to recall specific aspects 6 times:

• Twice immediately after seeing the film.
• Twice a week after seeing the film.
• Once during hypnosis.
• Once after hypnosis.

The result was that high hypnotizability subjects (SHSS:C) recalled morecumulative items in hypnosis than they did just before hypnosis. Lowhypnotizability subjects did not remember more during hypnosis. Thismatches our expectation of hypermnesia, that hypnosis facilitates recall forgood hypnotic subjects.

Most interestingly, both high and low hypnotizability subjects alsomade more cumulative errors during hypnosis than just before hypnosis,though the effect was stronger with highly hypnotizable subjects.

One explanation of this kind of result from experiments is that the hypnoticcontext causes subjects to adopt a looser reporting criterion, and they aremotivated to produce more information, containing both correct and incorrect(where there is no clear memory) details. See Klatzky and Erdely, 1985, "Theresponse criterion problem in tests of hypnosis and memory," InternationalJournal of Clinical and Experimental Hypnosis", 33, 246-257 for furtherdiscussion of this report criterion issue.