Mh. Erdelyi, HYPNOTIC HYPERMNESIA - THE EMPTY SET OF HYPERMNESIA, International journal of clinical and experimental hypnosis, 42(4), 1994, pp. 379-390
Although a long tradition exists suggesting that hypnosis can enhance
memory (hypnotic hypermnesia), the experimental literature is quite mi
xed. When, however, laboratory studies are classified according to the
type of stimulus and memory tests employed, a remarkable orderliness
of outcomes emerges: Recall tests for high-sense stimuli (e.g., poetry
, meaningful pictures) almost always produce hypermnesia, but not reco
gnition tests for low-sense stimuli (e.g., nonsense syllables, word li
sts). An important methodological issue is whether the recall incremen
ts for high-sense stimuli constitute enhanced memory or enhanced repor
ting (laxer response criteria). Recent laboratory literatures show tha
t, beyond response criterion effects, true memory enhancement (hypermn
esia) exists. Experiments conducted over the past decade, however, dem
onstrate that it is repeated retrieval effort and not hypnosis that is
responsible for hypermnesia: Repeated testing without hypnosis yields
as much hypermnesia as with hypnosis.