Giuliana Mazzoni

Imagination Can Create False Autobiographical Memories

Previous studies have shown that imagining an event can alter autobiographical beliefs. The current study examined whether it can also create false memories. One group of participants imagined a relatively frequent event and received information about an event that never occurs. A second group imagined the nonoccurring event and received information about the frequent event. One week before and again 1 week immediately after the manipulation, participants rated the likelihood that they had experienced each of the two critical events and a series of noncritical events, using the Life Events Inventory. During the last phase, participants were also asked to describe any memories they had for the events. For both events, imagination increased the number of memories reported, as well as beliefs about experiencing the event. These results indicate that imagination can induce false autobiographical memories.

JUDGMENTS OF LEARNING ARE AFFECTED BY THE KIND OF ENCODING IN WAYS THAT CANNOT BE ATTRIBUTED TO THE LEVEL OF RECALL

The authors investigated the theoretical question of whether different kinds of encoding can affect judgments of learning (JOLs) beyond any indirect effects arising from the differences those kinds of encoding produce on the likelihood of recall. They found that JOLs were more accurate after encoding by means of intentional learning than after encoding by means of incidental learning, even when the likelihood of recall did not differ for those kinds of encoding (Experiment 1), and were more accurate when intentional encoding occurred by generating the responses than by reading the responses (Experiment 2). An aggregation effect for JOLs was also discovered: Making JOLs about the likelihood of recall for an aggregate of items yielded less overconfidence (and even underconfidence) in contrast to the typical overconfidence of item-by-item JOLs. The overall pattern of findings suggests that JOLs are theoretically rich and are based on more than whatever underlies the likelihood of recall.

Do memorability ratings affect study-time allocation?

This research addresses the relation between predicting futureimemery performance (judgment of learning, or JOL) and subsequent self-paced study-time allocation. The results of three experiments support the main hypotheses: (1) recall increases with increasing JOL, (2) restudy increases JOL accuracy, and (3) study time is related to JOL. This last relation depends on the length of initial presentation time of the items. When the initial exposure trials were short, the most restudy time was allocated to the items judged hard to recall, but when the initial exposure times were long, the most restudy time was allocated to the uncertain items. Items studied longer were recalled equally well (Experiments 1 and 3) or to a lesser extent (Experiment 2) than items studied for a shorter time. It is hypothesized that during study time, subjects refine their JOLs for the items initially less well discriminated.

Changing beliefs and memories through dream interpretation

Autobiographical memory is malleable, but how much can we change peoples beliefs and memories about the past? We approached this question with a method designed to supply subjects with a highly personalized suggestion about what probably happened in their childhood. In the current study, one group of subjects (the ‘Dream’ subjects) had their dreams interpreted to indicate that they had experienced a critical childhood event (e.g. being harassed by a bully) before the age of 3. Relative to control subjects who did not receive personalized suggestion, the Dream subjects were more likely to increase their belief that they had the critical experience, and approximately half of these also produced concrete memory reports. These findings are discussed in terms of their implications for autobiographical memory, and also for psychotherapy practice. Copyright

Hypnotic suggestibility, cognitive inhibition, and dissociation

We examined two potential correlates of hypnotic suggestibility: dissociation and cognitive inhibition. Dissociation is the foundation of two of the major theories of hypnosis and other theories commonly postulate that hypnotic responding is a result of attentional abilities (including inhibition). Participants were administered the Waterloo-Stanford Group Scale of Hypnotic Susceptibility, Form C. Under the guise of an unrelated study, 180 of these participants also completed: a version of the Dissociative Experiences Scale that is normally distributed in non-clinical populations; a latent inhibition task, a spatial negative priming task, and a memory task designed to measure negative priming. The data ruled out even moderate correlations between hypnotic suggestibility and all the measures of dissociation and cognitive inhibition overall, though they also indicated gender differences. The results are a challenge for existing theories of hypnosis.

Growth hormone releasing hormone improves the cognition of healthy older adults

Declines in the activity of the somatotrophic axis have been implicated in the age-related changes observed in a number of physiological functions, including cognition. Such age-related changes may be arrested or partially reversed by hormonal supplementation. We examined the effect of 6 months treatment with daily growth hormone releasing hormone (GHRH) or placebo on the cognition of a group of 89 healthy older (68.0+/-0.7) adults. GHRH resulted in improved performance on WAIS-R performance IQ (p<0.01), WAIS-R picture arrangement (p<0.01), finding As (p<0.01), verbal sets (p<0.01) and single-dual task (p<0.04). GHRH-based improvements were independent of gender, estrogen status or baseline cognitive capacity. These results demonstrate that the age-related decline in the somatotrophic axis may be related to age-related decline in cognition. Further they indicate that supplementation of this neuro-hormonal axis may partially ameliorate such cognitive declines in healthy normal older adults and potentially in individuals with impaired cognitive function (i.e., mild cognitive impairment and Alzheimers disease).

Suggested visual hallucination without hypnosis enhances activity in visual areas of the brain

This functional Magnetic Resonance Imaging (fMRI) study investigated high and low suggestible people responding to two visual hallucination suggestions with and without a hypnotic induction. Participants in the study were asked to see color while looking at a grey image, and to see shades of grey while looking at a color image. High suggestible participants reported successful alterations in color perception in both tasks, both in and out of hypnosis, and showed a small benefit if hypnosis was induced. Low suggestible people could not perform the tasks successfully with or without the hypnotic induction. The fMRI results supported the self report data, and changes in brain activity were found in a number of visual areas. The results indicate that a hypnotic induction, although having the potential to enhance the ability of high suggestible people, is not necessary for the effective alteration of color perception by suggestion.

Immediate and persisting effects of misleading questions and hypnosis on memory reports.

Immediate and persisting effects of misleading questions and hypnosis on memory reports were assessed. After listening to a story, 52 highly suggestible students and 59 low and medium suggestible students were asked misleading or neutral questions in or out of hypnosis. All participants were then asked neutral questions without hypnosis. Both hypnosis and misleading questions significantly increased memory errors, and misleading questions produced significantly more errors than did hypnosis. The 2 effects were additive, so that misleading questions in hypnosis produced the greatest number of errors. There were no significant interactions with level of hypnotic suggestibility. Implications of these findings for the per se exclusion of posthypnotic testimony are discussed.

The Role of Belief in Occurrence Within Autobiographical Memory

This article examines the idea that believing that events occurred in the past is a non-memorial decision that reflects underlying processes that are distinct from recollecting events. Research on autobiographical memory has often focused on events that are both believed to have occurred and remembered, thus tending to overlook the distinction between autobiographical belief and recollection. Studying event representations such as false memories, believed-not-remembered events, and non-believed memories shows the influence of non-memorial processes on evaluations of occurrence. Believing that an event occurred and recollecting an event may be more strongly dissociated than previously stated. The relative independence of these constructs was examined in 2 studies. In Study 1, multiple events were cued, and then each was rated on autobiographical belief, recollection, and other memory characteristics. In Study 2, participants described a nonbelieved memory, a believed memory, and a believed-not-remembered event, and they made similar ratings. In both studies, structural equation modeling techniques revealed distinct belief and recollection latent variables. Modeling the predictors of these factors revealed a double dissociation: Perceptual, re-experiencing, and emotional features predicted recollection and not belief, whereas event plausibility strongly predicted belief and weakly predicted recollection. The results show that judgments of autobiographical belief and recollection are distinct, that each is influenced by different sources of information and processes, and that the strength of their relationship varies depending on the type of event under study. The concept of autobiographical belief is elaborated, and implications of the findings are discussed in relation to decision making about events, social influence on memory, metacognition, and recognition processes.

Neuroimaging resolution of the altered state hypothesis

A controversy in the field of hypnosis has centered on the question of whether there is a uniquely hypnotic state of consciousness and, if so, whether it is causally related to responsiveness to suggestion. Evidence from brain imaging studies has been used to support claims for various altered state hypotheses, without resolving the debate. The designs of many neuroimaging studies confound the induction of hypnosis with the suggestions that can be given in or out of hypnosis, thus rendering them incapable of resolving the controversy. Brain imaging studies that do not have this confound support the hypothesis that hypnotic inductions produce changes in brain activity, but also indicate that these changes are not required for the experience of hypnotic suggestions or their neural correlates. The data remain equivocal as to whether there is a causal relation between the changes in brain activity produced by hypnotic inductions and those produced by other suggestions. It also remains uncertain whether the changes in activation produced by hypnotic inductions reflect a uniquely hypnotic state as opposed to more mundane processes.