Orne, M.T. The use and misuse of hypnosis in court. International ...

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Orne 1979 IJCEHhttp://www.sas.upenn.edu/psych/history/orne/orneijceh19794311341.html6 de 23 19/03/2012 17:24details, puts pressure on the subject to provide information for which few, if any, actual memories areavailable. This situation may jog the subject's memory and produce some increased recall, but it will alsocause him to fill in details that are plausible but consist of memories or fantasies from other times. It isextremely difficult to know which aspects of hypnotically aided recall are318 MARTIN T. ORNEhistorically accurate and which aspects have been confabulated. The details of material that isconfabulated depend upon the subject's total past experience and all available cues relevant to thehypnotic task. Subjects will use prior information and cues in an inconsistent and unpredictable fashion; insome instances such information is incorporated in what is confabulated, while in others the hypnoticrecall may be virtually unaffected.As a consequence of these limitations, hypnosis may be useful in some instances to help bring backforgotten memories following an accident or a crime while in others a witness might, with the sameconviction, produce information that is totally inaccurate. This means that material produced duringhypnosis or immediately after hypnosis, inspired by hypnotic revivification, may or may not be historicallyaccurate. As long as this material is subject to independent verification, its utility is considerable and therisk attached to the procedure minimal. There is no way, however, by which anyone--even a psychologistor psychiatrist with extensive training in the field of hypnosis--can for any particular piece of informationdetermine whether it is an actual memory versus a confabulation unless there is independent verification.Thus, there are instances when subsequently verified accurate license plate numbers were recalled inhypnosis by individuals who previously could not remember them. In the Chowchilla kidnapping case(Kroger & Douce, 1979), the license plate number was helpful in the initial investigation of the case(although ultimately not required in the courtroom because of the abundance of other evidence available).On the other hand, a good many license plate numbers that have been recalled under hypnosis bywitnesses in other cases in fact belonged to individuals where it turned out, after investigation, that neitherthey nor their cars could have been involved.Hypermnesia by Direct SuggestionAnother approach which has been used to increase memory is direct suggestion. While generally used toenhance recall for recent events, it can also be employed to induce hypermnesia for the distant past.Stalnaker and Riddle (1932) used direct suggestion to facilitate recall of long forgotten memories,shedding light on the mechanism of hypermnesia. It was suggested to deeply hypnotized subjects that theywould recall prose and verse that they had committed to memory in grade school. In hypnosis, thesesubjects appeared to remember the material far more easily, with far better recall, than in the wake state.Careful analysis, however, showed that, while some additional material was recalled in hypnosis, theamount was far less than it first seemed; in fact, subjects showed a pronounced tendency to confabulate sothat319 USE AND MISUSE OF HYPNOSIS IN COURTmany of the new phrases "recalled" had simply been improvised in a style that superficially resembled theauthor's. Often these confabulations were sufficiently good so as not to be easily recognized as such oncasual examination. This study clearly established two tendencies in hypnotic hypermnesia: (a) a modestincrease in the amount of material available to memory, and (b) a tendency to confabulate--to fill in thoseaspects which the individual cannot remember, in an effort to comply with the suggestions of thehypnotist. More recent studies, such as those of White, Fox, and Harris (1940), Sears (1954), and Dhanensand Lundy (1975), appear to show increased recall of meaningful, though nontraumatic, material inhypnosis. (No such effect has been demonstrated with nonsense syllables.) However, when the effects of
Orne 1979 IJCEHhttp://www.sas.upenn.edu/psych/history/orne/orneijceh19794311341.html7 de 23 19/03/2012 17:24hypnosis on increased memory are compared with those of increased motivation (Cooper & London,1973), and procedures analogous to hypnosis with unhypnotizable subjects (Dhanens & Lundy, 1975),there is no significantly greater increase in recall with hypnosis. Thus, the widely held belief that hypnoticsuggestion can not only increase the amount but also the reliability of the material recalled ignoresmotivational factors on the one hand, and the concurrent dramatic increase in the "recall" of inaccurateinformation on the other. This is illustrated in the Stalnaker and Riddle study (1932). Depending upon howthey scored their material, these investigators could observe a 65 % increase in memory for materiallearned many years earlier when recalled during hypnosis rather than in the wake state. Such a figure isobtained if one simply looks at the amount of more accurate memories that are brought forth. At the sametime, however, subjects in the hypnotic condition vastly increased the amount of inaccurate details thatwere "remembered."The apparently increased recall in hypnosis can in large part be understood if one takes into account thedeeply hypnotized individual's tendency to manifest a decrease in critical judgment. The same processwhich increases suggestibility by permitting the subject to accept counterfactual suggestions as real alsomakes it possible for the subject to accept approximations of memory as accurate. In the wake state he isunwilling to consider approximate or fragmentary memories as acceptable recall; however, in hypnosis healters his criterion of what is acceptable and brings forth accurately recalled fragments mixed withconfabulated material.6 When hypnosis is used in the context of gathering investigative leads, such achange in criterion is desirable since it will cause a witness to bring forth bits of information which hewould not6 This process may well be analogous to a change in subjective criterion of sensory thresholds of the kindwhich led to the application of signal detection theory to problems of psychophysics.320 MARTIN T. ORNEotherwise have felt confident enough to report--provided, of course, one recognizes that these fragmentsare made available at the cost of adding other details which are likely to be inaccurate. Further, neither thesubject nor the expert observer can distinguish between confabulation and accurate recall in any particularinstance. The only way this can be accomplished is on the basis of external corroborative data.The Confusion of Memories during Hypnosis with Waking Recall and Its Effect on Subjective ConvictionWhen a subject is hypnotized and told to remember the events of a particular day (and awakened withoutamnesia suggestions), he may be able subsequently, in the wake state, to describe his recollections inhypnosis and clearly differentiate them from his earlier recollections before being hypnotized. It is anothermatter, however, if the subject is convinced before being hypnotized that he will have the "true facts" thathe is now unable to remember, or if prior to awakening, the subject is given the suggestion that he willwake up and remember everything, including the details of what actually occurred on that particular day,and that he will be able to recall all details as vividly and clearly in the wake state as in hypnosis. Underthese circumstances, he will typically awaken and confound the hypnotic memories with his wakingmemories. Such suggestions, which are now widely used for forensic purposes, result in the individual'stending to accept the events he relived in hypnosis as if they were what actually happened. The previousgaps or uncertainties in his memory are now filled in, and the events as they were relived in hypnosisbecome his recollection of what actually occurred on the day in question.The witness who testifies following such a procedure may even fail to be able to distinguish which of hismemories occurred in hypnosis and which came about as part of his normal waking recollection. Insteadof differentiating between his earlier fragmentary recall and the gaps that have been filled in--perhaps bypseudomemories created during hypnosis--he experiences the totality as his recollection of what hadoriginally transpired. It is this new recollection that is convincingly reported when the individual is askedwhat happened. Even though prior to hypnosis he had been very uncertain about his memory, had
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