Are hypnotically induced pseudomemories resistant to cross-examination?

Abstract

Two experiments examined the effects of hypnotic procedures in response to interrogation and crossexamination in subjects who viewed a simulated robbery. Experiment 1 found that hypnotic and nonhypnotic leading interrogations were equally likely to produce misattributions and misidentification of mug shots. Moreover, under cross-examination subjects who had been given an hypnotic interrogation and those given nonhypnotic interrogations were equally likely to disavow their earlier misattributions and misidentifications. In both hypnotic and nonhypnotic treatments high hypnotizables were more likely than low hypnotizables to misattribute characteristics during interrogation and to disavow earlier misattributions during cross-examination. In Experiment 2 high hypnotizables given a cross-examination that legitimated their earlier errors as honest mistakes and that enabled them to disavow earlier testimony without discrediting themselves (hidden observer treatment) showed the highest and most consistent rates of disavowel. A stringent cross-examination that implied that subjects had been careless or dishonest during interrogation produced the lowest rates of disavowel.

Creating false memories of infancy with hypnotic and non-hypnotic procedures

“…high hypnotizables) are particularly likely to form suggestion-induced false memories. In support of this hypothesis, a good deal of research has demonstrated a positive relationship between hypnotizability and false memory reporting in both hypnotic and non-hypnotic contexts (Barnier and McConkey, 1992;McConkey et al, 1990;Sheehan et al, 1991;Spanos et al, 1989). Relatedly, a number of studies (reviewed by McConkey, 1992) indicate that, in eyewitness recall situations, hypnotizability often correlates signi®cantly with the degree of con®dence that people place in their recall, even when that recall is inaccurate.…”

Is there a future for investigative hypnosis?

“…Whether or not a hypnotic procedure produces adverse effects will depend on the particular social demands and expectations, and individual characteristics of the interviewees, present in the particular situation, and, indeed, the empirical evidence suggests only that hypnotic procedures can produce adverse effects on testimony, not that they will inevitably do so. For example, Spanos et al (1989) found that hypnotic procedures per se were no more likely to produce memory distortions, than non-hypnotic procedures, but individuals classifi ed as highly hypnotisable were generally more likely to produce memory distortions in both hypnotic and non-hypnotic conditions. Also, as noted previously, other research suggests that hypnotically induced inaccuracies may often refl ect reporting biases rather than genuine irreversible memory distortions (that is, subjects report false information because they think the situation requires it of them, rather than because their memories are impaired).…”

“…Also, as noted previously, other research suggests that hypnotically induced inaccuracies may often refl ect reporting biases rather than genuine irreversible memory distortions (that is, subjects report false information because they think the situation requires it of them, rather than because their memories are impaired). Thus, hypnotically created pseudomemories and false confi dence effects can be signifi cantly reduced and/or reversed to non-hypnotic levels under conditions that encourage more cautious and truthful reporting (Barnier & McConkey, 1995;McConkey et al, 1990;Murray, Cross, & Whipple, 1992;Sheehan, Green, & Truesdale, 1992;Spanos et al 1989;Wagstaff & Frost, 1996). Thus, instead of dismissing the whole of the testimony of the witness who has previously been 'hypnotized', perhaps we might more usefully ask what might be the effects of this particular hypnosis session on particular statements made by this particular witness?…”

“…In coming to this conclusion, experts in this area have placed considerable emphasis on the weight of evidence from experimental studies. Although there are a few exceptions (see, for example, Geiselman, Fisher, MacKinnon, & Holland, 1985;Ready, Bothwell, & Brigham, 1997), the evidence shows, fairly overwhelmingly, that hypnotic procedures do not signifi cantly improve accurate eyewitness recall to levels above those achievable under non-hypnotic conditions (for reviews, see Erdelyi, 1994;Kebbell & Wagstaff, 1998;McConkey & Sheehan, 1995;Smith, 1983;Steblay & Bothwell, 1994;Wagstaff, 1984; and for examples, see Baker, Haynes, & Patrick, 1983;Buckhout, Eugenio, Licitra, Oliver, & Kramer, 1981;Dywan & Bowers, 1983;Gregg & Mingay, 1987;Kebbell & Wagstaff, 1997;Mingay, 1986;Nogrady, McConkey, & Perry, 1985;Putnam, 1979;Register & Kihlstrom, 1987;Sanders & Simmons, 1983;Scoboria, Mazzoni, Kirsch, & Milling, 2002;Sheehan, Grigg, & McCann, 1984;Sheehan & Tilden, 1983, 1986Spanos, Gwynn, Comer, Baltruweit, & de Groh, 1989;Spanos, Quigley, Gwynn, Glatt, & Perlini, 1991;Wagstaff, 1982a ;Wagstaff & Ovenden, 1979;Wagstaff & Sykes, 1983;Wagstaff, Brunas-Wagstaff, Knapton, Winterbottom, Crean, Cole, & Wheatcroft, 2004;Wagstaff, Traverse, & Milner, 1982;Yuille & McEwan, 1985;Zelig & Beidleman, 1981). The absence of any superiority for hypnotic procedures is evident regardless of the nature of the hypnotic materials (objects, faces, people, words), the way they are presented (incidentally, intentionally, on slides, fi lms, ...…”

“…In support of the response bias explanation, a variety of evidence suggests that incorrect information and false confi dence effects produced during hypnosis can sometimes be reduced to non-hypnotic levels under conditions that encourage more cautious and truthful reporting. Such conditions include telling interviewees that a 'hidden-part' of them can describe their 'real' memories, cross-examining them under oath (Spanos et al, 1989), giving them a fi nancial incentive for accurate reporting (Murray, Cross, & Whipple, 1992), or providing them with an opportunity to deny being in a 'trance' (Wagstaff & Frost, 1996). False memory reports with hypnosis are also reduced when it is implied that the experiment is terminated (Barnier & McConkey, 1995), when subjects are contacted by telephone at their home after the experiment (McConkey, Labelle, Bibb, & Bryant, 1990), and when rapport with the hypnotist is downgraded (Sheehan, Green, & Truesdale, 1992).…”