یک پارادایم خواب آور برای مطالعه خاطرات مزاحم

Abstract Despite the importance of intrusive memories in clinical disorders, research has been limited by a dearth of paradigms that permit experimental study of intrusions. This study describes a hypnotic paradigm for eliciting intrusive memories. Forty-nine highly hypnotisable participants nominated a distressing memory prior to being hypnotised. During hypnosis, they received the suggestion that they would remember the memory in response to a designated cue after the hypnosis session. Half of the participants also received a posthypnotic amnesia suggestion for the source of the memory. Following hypnosis, all participants completed a cognitive task and during the task received the cue to recall the memory. Results demonstrated that memories experienced after posthypnotic amnesia were experienced as more involuntary and more distressing than those that were knowingly retrieved. Participants in the posthypnotic amnesia condition also demonstrated greater interference on the cognitive task after the retrieval cue was given than those who intentionally retrieved the memory. These findings suggest that posthypnotic suggestion provides a useful paradigm to elicit intrusive memories under experimental conditions.

. Results 2.1. Preliminary analyses Table 1 presents the means for participant characteristics across retrieval conditions. Separate one-way analyses of variance (ANOVA) indicated that groups did not differ on age, HGSHS:A scores, or SHSS:C scores. All participants reported a distressing memory (relationship separation = 25; death of loved one/pet = 12; accident = 7; other = 4). Table 1 presents the means for participants’ ratings of the qualities of the memory they nominated prior to hypnosis. There were no differences in terms of type of event reported, or involuntariness, frequency, distress, or vividness across retrieval conditions. Performance on the sustained attention task was not associated with any participant characteristics of hypnotisability score. Table 1. Participant characteristics. Posthypnotic amnesia Intentional retrieval Age 19.33 (1.61) 21.25 (8.16) HGSHS:A 8.00 (0.63) 8.69 (0.93) SHSS:C 8.09 (0.98) 8.42 (1.12) Memory involuntariness 4.97 (2.63) 5.11 (2.65) Memory frequency 4.96 (2.36) 4.60 (2.78) Memory distress 6.54 (1.89) 5.69 (2.24) Memory vividness 7.12 (1.60) 6.75 (1.85) Note. Standard deviations appear in parentheses. HGSHS:A = Harvard Group Scale of Hypnotic Susceptibility, Form A. SHSS:C = Stanford Hypnotic Susceptibility Scale, Form C. Table options 2.2. Manipulation checks Comparable numbers of participants did not recall the target memory in the experimental posthypnotic phase in posthypnotic amnesia (n = 4) and intentional retrieval condition (n = 6) conditions, χ2 (1, n = 10) = 0.51, p > 0.05. These 10 participants were excluded from subsequent analyses. In terms of the reported reason for recalling the memory, more participants in the posthypnotic amnesia condition (95%) than intentional retrieval condition (12%) reported not knowing why they had recalled the memory [χ2 (n = 47) = 14.39, p < 0.001]. One participant in the posthypnotic amnesia condition reported explicitly remembering the memory suggestion, and accordingly was excluded from subsequent analyses. The resulting sample comprised of 19 participants in the posthypnotic amnesia condition and 18 participants in the intentional retrieval condition. 2.3. Qualitative features of recalled memories Table 2 presents the mean ratings for involuntariness, distress, and vividness of memories made during the experimental phase. Participants in the posthypnotic amnesia condition reported that the memory was more involuntary [F(1,35) = 14.85, p < 0.001, ή = 0.32], and more distressing [F(1,35) = 1.96, p = 0.05, ή = 0.11] than participants in the intentional retrieval condition. Table 2 also presents the mean ratings of memory qualities made by the independent rater of the postexperimental ratings. Participants in the posthypnotic amnesia condition reported that the memory was more involuntary [F(1,35) = 11.27, p < 0.005, ή = 0.27]. No differences were noted for vividness or distress ratings by participants or by independent raters. Table 2. Mean ratings of memory qualities. Posthypnotic amnesia Intentional retrieval Experimental ratings Involuntariness 8.44 (0.65) 5.71 (2.66) Distress 6.35 (1.73) 5.12 (1.93) Vividness 6.41 (2.06) 6.68 (1.88) Postexperimental ratings Involuntariness 4.56 (1.10) 2.87 (1.77) Distress 2.80 (1.36) 2.39 (1.50) Vividness 3.35 (1.37) 3.13 (1.36) Note: Standard deviations in parentheses. Table options 2.4. Cognitive task performance Table 3 presents participants’ mean performance on the cognitive task before and after recall of the memory. A 2 (Retrieval Condition) × 2 (Task Order) × 2 (Time) ANOVA of correct responses on the cognitive task indicated a significant Retrieval Condition × Time interaction effect [F (1, 35) = 4.35, p < 0.05, ή = 0.12], a significant Task Order × Time interaction effect [F (1, 35) = 12.53, p < 0.001, ή = 0.28], and a significant three-way Retrieval Condition × Task Order × Time interaction effect [F (1, 35) = 4.22, p < 0.05, ή = 0.12]. To clarify the three-way interaction, we conducted separate 2 (Retrieval Condition) × 2 (Time) ANOVAs for participants who performed Task A or Task B, initially. For participants who completed Task B first, there were no significant main or interaction effects. For participants who completed Task A first, there was a significant main effect for Time [F (1, 16) = 26.32, p < 0.001, ή = 0.62] and a significant Time × Retrieval Condition interaction effect [F (1, 16) = 17.28, p < 0.001, ή = 0.52]. Follow-up comparisons indicated that after the memory retrieval cue, participants in the posthypnotic amnesia condition had a greater decrement in performance relative to their pre-retrieval cue than participants in the intentional retrieval condition (p < 0.05). Table 3. Mean performance on cognitive task. Posthypnotic amnesia Intentional retrieval Order 1 Order 2 Order 1 Order 2 Pre-recall 17.55 (5.18) 14.71 (2.06) 17.14 (3.43) 15.55 (3.83) Post-recall 12.09 (5.41) 15.86 (3.29) 16.57 (3.87) 16.73 (3.85) Note: Standard deviations appear in parentheses.