International Handbook of Clinical Hypnosis - E-Lib FK UWKS

50 INTERNATIONAL HANDBOOK OF CLINICAL HYPNOSIS
THE NATURE OF MEMORY
Memory is equally a complex process. It is a labile phenomenon and its inherent
plasticity is clearly acknowledged in the literature e.g., Annon, 1988). It is
in¯uenced strongly by pre-existing representations Echabe & Rovira, 1989), but
postevent misinformation is also effective and known to lead to distortion of
memory in both adults and children e.g., Ceci, Ross & Toglia, 1987).
In general, memory is a constructive and reconstructive process. There is
substantial evidence that it changes over time to accommodate alterations in
feelings toward or information about the events) being remembered. Hypnosis
may lead to an increase in the amount of material reported as memory. However,
whereas some of the additional material may be accurate, other aspects of it may
be inaccurate; and this is despite the fact that the person may be substantially
con®dent about the accuracy of the material that is reported.
ILLUSTRATIVE PHENOMENA
By way of illustration, it seems most instructive to single out pseudomemories, and
memories of past, personal events recorded in the clinical setting by use of
hypnosis. These two phenomena are selected because they both illustrate the rich
variety of the complex processes and factors that are frequently at work.
PSEUDOMEMORY
The phenomenon of pseudomemory is tied necessarily to subjects' acceptance of
postevent misinformation. In operational terms, the conditions for establishing it in
the hypnotic setting typically involve the administration of suggestions giving false
information to subjects following the induction of hypnosis. Routinely, subjects are
awakened subsequently and then tested for how well they remembered the events
that they saw earlier.
Empirically, there is a range of parameters that has been shown to be related to
hypnotically induced pseudomemory, but not all of them have produced reliable
results. Incidence of the phenomenon is variable, the most consistent evidence that
has emerged being that level of hypnotic susceptibility is related positively to the
phenomenon, with high susceptible subjects showing greater evidence of pseudomemory
than low susceptible subjects.
The evidence for the relevance of hypnotic skill comes from a variety of studies
that have now used a range of paradigms for studying pseudomemory. Labelle,
Laurence, Nadon & Perry 1990), for instance, found that pseudomemories were
reported most often by highly susceptible subjects, and not at all by low susceptible
subjects: and this pattern of ®ndings was largely replicated by McConkey, Labelle,
Bibb & Bryant 1990). Relatively few studies have used nonhypnotic comparison