<strong>Orne</strong> 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 <strong>in</strong>formation for which few, if any, actual memories areavailable. This situation may jog the subject's memory <strong>and</strong> produce some <strong>in</strong>creased recall, but it will alsoca<strong>use</strong> him to fill <strong>in</strong> details that are plausible but consist <strong>of</strong> memories or fantasies from other times. It isextremely difficult to know which aspects <strong>of</strong> hypnotically aided recall are318 MARTIN T. ORNEhistorically accurate <strong>and</strong> which aspects have been confabulated. <strong>The</strong> details <strong>of</strong> material that isconfabulated depend upon the subject's total past experience <strong>and</strong> all available cues relevant to thehypnotic task. Subjects will <strong>use</strong> prior <strong>in</strong>formation <strong>and</strong> cues <strong>in</strong> an <strong>in</strong>consistent <strong>and</strong> unpredictable fashion; <strong>in</strong>some <strong>in</strong>stances such <strong>in</strong>formation is <strong>in</strong>corporated <strong>in</strong> what is confabulated, while <strong>in</strong> others the hypnoticrecall may be virtually unaffected.As a consequence <strong>of</strong> these limitations, <strong>hypnosis</strong> may be <strong>use</strong>ful <strong>in</strong> some <strong>in</strong>stances to help br<strong>in</strong>g backforgotten memories follow<strong>in</strong>g an accident or a crime while <strong>in</strong> others a witness might, with the sameconviction, produce <strong>in</strong>formation that is totally <strong>in</strong>accurate. This means that material produced dur<strong>in</strong>g<strong>hypnosis</strong> or immediately after <strong>hypnosis</strong>, <strong>in</strong>spired by hypnotic revivification, may or may not be historicallyaccurate. As long as this material is subject to <strong>in</strong>dependent verification, its utility is considerable <strong>and</strong> therisk attached to the procedure m<strong>in</strong>imal. <strong>The</strong>re is no way, however, by which anyone--even a psychologistor psychiatrist with extensive tra<strong>in</strong><strong>in</strong>g <strong>in</strong> the field <strong>of</strong> <strong>hypnosis</strong>--can for any particular piece <strong>of</strong> <strong>in</strong>formationdeterm<strong>in</strong>e whether it is an actual memory versus a confabulation unless there is <strong>in</strong>dependent verification.Thus, there are <strong>in</strong>stances when subsequently verified accurate license plate numbers were recalled <strong>in</strong><strong>hypnosis</strong> by <strong>in</strong>dividuals who previously could not remember them. In the Chowchilla kidnapp<strong>in</strong>g case(Kroger & Douce, 1979), the license plate number was helpful <strong>in</strong> the <strong>in</strong>itial <strong>in</strong>vestigation <strong>of</strong> the case(although ultimately not required <strong>in</strong> the <strong>court</strong>room beca<strong>use</strong> <strong>of</strong> the abundance <strong>of</strong> other evidence available).On the other h<strong>and</strong>, a good many license plate numbers that have been recalled under <strong>hypnosis</strong> bywitnesses <strong>in</strong> other cases <strong>in</strong> fact belonged to <strong>in</strong>dividuals where it turned out, after <strong>in</strong>vestigation, that neitherthey nor their cars could have been <strong>in</strong>volved.Hypermnesia by Direct SuggestionAnother approach which has been <strong>use</strong>d to <strong>in</strong>crease memory is direct suggestion. While generally <strong>use</strong>d toenhance recall for recent events, it can also be employed to <strong>in</strong>duce hypermnesia for the distant past.Stalnaker <strong>and</strong> Riddle (1932) <strong>use</strong>d direct suggestion to facilitate recall <strong>of</strong> long forgotten memories,shedd<strong>in</strong>g light on the mechanism <strong>of</strong> hypermnesia. It was suggested to deeply hypnotized subjects that theywould recall prose <strong>and</strong> verse that they had committed to memory <strong>in</strong> grade school. In <strong>hypnosis</strong>, thesesubjects appeared to remember the material far more easily, with far better recall, than <strong>in</strong> the wake state.Careful analysis, however, showed that, while some additional material was recalled <strong>in</strong> <strong>hypnosis</strong>, theamount was far less than it first seemed; <strong>in</strong> fact, subjects showed a pronounced tendency to confabulate sothat319 USE AND MISUSE OF HYPNOSIS IN COURTmany <strong>of</strong> the new phrases "recalled" had simply been improvised <strong>in</strong> a style that superficially resembled theauthor's. Often these confabulations were sufficiently good so as not to be easily recognized as such oncasual exam<strong>in</strong>ation. This study clearly established two tendencies <strong>in</strong> hypnotic hypermnesia: (a) a modest<strong>in</strong>crease <strong>in</strong> the amount <strong>of</strong> material available to memory, <strong>and</strong> (b) a tendency to confabulate--to fill <strong>in</strong> thoseaspects which the <strong>in</strong>dividual cannot remember, <strong>in</strong> an effort to comply with the suggestions <strong>of</strong> thehypnotist. More recent studies, such as those <strong>of</strong> White, Fox, <strong>and</strong> Harris (1940), Sears (1954), <strong>and</strong> Dhanens<strong>and</strong> Lundy (1975), appear to show <strong>in</strong>creased recall <strong>of</strong> mean<strong>in</strong>gful, though nontraumatic, material <strong>in</strong><strong>hypnosis</strong>. (No such effect has been demonstrated with nonsense syllables.) However, when the effects <strong>of</strong>
<strong>Orne</strong> 1979 IJCEHhttp://www.sas.upenn.edu/psych/history/orne/orneijceh19794311341.html7 de 23 19/03/2012 17:24<strong>hypnosis</strong> on <strong>in</strong>creased memory are compared with those <strong>of</strong> <strong>in</strong>creased motivation (Cooper & London,1973), <strong>and</strong> procedures analogous to <strong>hypnosis</strong> with unhypnotizable subjects (Dhanens & Lundy, 1975),there is no significantly greater <strong>in</strong>crease <strong>in</strong> recall with <strong>hypnosis</strong>. Thus, the widely held belief that hypnoticsuggestion can not only <strong>in</strong>crease the amount but also the reliability <strong>of</strong> the material recalled ignoresmotivational factors on the one h<strong>and</strong>, <strong>and</strong> the concurrent dramatic <strong>in</strong>crease <strong>in</strong> the "recall" <strong>of</strong> <strong>in</strong>accurate<strong>in</strong>formation on the other. This is illustrated <strong>in</strong> the Stalnaker <strong>and</strong> Riddle study (1932). Depend<strong>in</strong>g upon howthey scored their material, these <strong>in</strong>vestigators could observe a 65 % <strong>in</strong>crease <strong>in</strong> memory for materiallearned many years earlier when recalled dur<strong>in</strong>g <strong>hypnosis</strong> rather than <strong>in</strong> the wake state. Such a figure isobta<strong>in</strong>ed if one simply looks at the amount <strong>of</strong> more accurate memories that are brought forth. At the sametime, however, subjects <strong>in</strong> the hypnotic condition vastly <strong>in</strong>creased the amount <strong>of</strong> <strong>in</strong>accurate details thatwere "remembered."<strong>The</strong> apparently <strong>in</strong>creased recall <strong>in</strong> <strong>hypnosis</strong> can <strong>in</strong> large part be understood if one takes <strong>in</strong>to account thedeeply hypnotized <strong>in</strong>dividual's tendency to manifest a decrease <strong>in</strong> critical judgment. <strong>The</strong> same processwhich <strong>in</strong>creases suggestibility by permitt<strong>in</strong>g the subject to accept counterfactual suggestions as real alsomakes it possible for the subject to accept approximations <strong>of</strong> memory as accurate. In the wake state he isunwill<strong>in</strong>g to consider approximate or fragmentary memories as acceptable recall; however, <strong>in</strong> <strong>hypnosis</strong> healters his criterion <strong>of</strong> what is acceptable <strong>and</strong> br<strong>in</strong>gs forth accurately recalled fragments mixed withconfabulated material.6 When <strong>hypnosis</strong> is <strong>use</strong>d <strong>in</strong> the context <strong>of</strong> gather<strong>in</strong>g <strong>in</strong>vestigative leads, such achange <strong>in</strong> criterion is desirable s<strong>in</strong>ce it will ca<strong>use</strong> a witness to br<strong>in</strong>g forth bits <strong>of</strong> <strong>in</strong>formation which hewould not6 This process may well be analogous to a change <strong>in</strong> subjective criterion <strong>of</strong> sensory thresholds <strong>of</strong> the k<strong>in</strong>dwhich led to the application <strong>of</strong> signal detection theory to problems <strong>of</strong> psychophysics.320 MARTIN T. ORNEotherwise have felt confident enough to report--provided, <strong>of</strong> course, one recognizes that these fragmentsare made available at the cost <strong>of</strong> add<strong>in</strong>g other details which are likely to be <strong>in</strong>accurate. Further, neither thesubject nor the expert observer can dist<strong>in</strong>guish between confabulation <strong>and</strong> accurate recall <strong>in</strong> any particular<strong>in</strong>stance. <strong>The</strong> only way this can be accomplished is on the basis <strong>of</strong> external corroborative data.<strong>The</strong> Confusion <strong>of</strong> Memories dur<strong>in</strong>g Hypnosis with Wak<strong>in</strong>g Recall <strong>and</strong> Its Effect on Subjective ConvictionWhen a subject is hypnotized <strong>and</strong> told to remember the events <strong>of</strong> a particular day (<strong>and</strong> awakened withoutamnesia suggestions), he may be able subsequently, <strong>in</strong> the wake state, to describe his recollections <strong>in</strong><strong>hypnosis</strong> <strong>and</strong> clearly differentiate them from his earlier recollections before be<strong>in</strong>g hypnotized. It is anothermatter, however, if the subject is conv<strong>in</strong>ced before be<strong>in</strong>g hypnotized that he will have the "true facts" thathe is now unable to remember, or if prior to awaken<strong>in</strong>g, the subject is given the suggestion that he willwake up <strong>and</strong> remember everyth<strong>in</strong>g, <strong>in</strong>clud<strong>in</strong>g the details <strong>of</strong> what actually occurred on that particular day,<strong>and</strong> that he will be able to recall all details as vividly <strong>and</strong> clearly <strong>in</strong> the wake state as <strong>in</strong> <strong>hypnosis</strong>. Underthese circumstances, he will typically awaken <strong>and</strong> confound the hypnotic memories with his wak<strong>in</strong>gmemories. Such suggestions, which are now widely <strong>use</strong>d for forensic purposes, result <strong>in</strong> the <strong>in</strong>dividual'stend<strong>in</strong>g to accept the events he relived <strong>in</strong> <strong>hypnosis</strong> as if they were what actually happened. <strong>The</strong> previousgaps or uncerta<strong>in</strong>ties <strong>in</strong> his memory are now filled <strong>in</strong>, <strong>and</strong> the events as they were relived <strong>in</strong> <strong>hypnosis</strong>become his recollection <strong>of</strong> what actually occurred on the day <strong>in</strong> question.<strong>The</strong> witness who testifies follow<strong>in</strong>g such a procedure may even fail to be able to dist<strong>in</strong>guish which <strong>of</strong> hismemories occurred <strong>in</strong> <strong>hypnosis</strong> <strong>and</strong> which came about as part <strong>of</strong> his normal wak<strong>in</strong>g recollection. Instead<strong>of</strong> differentiat<strong>in</strong>g between his earlier fragmentary recall <strong>and</strong> the gaps that have been filled <strong>in</strong>--perhaps bypseudomemories created dur<strong>in</strong>g <strong>hypnosis</strong>--he experiences the totality as his recollection <strong>of</strong> what hadorig<strong>in</strong>ally transpired. It is this new recollection that is conv<strong>in</strong>c<strong>in</strong>gly reported when the <strong>in</strong>dividual is askedwhat happened. Even though prior to <strong>hypnosis</strong> he had been very uncerta<strong>in</strong> about his memory, had