Memory states and memory tasks: an integrative framework for eyewitness memory and suggestibility

An integrative framework (IMP) is presented which depicts performance in eyewitness suggestibility experiments as the participants' solutions of memory tasks, depending on (a) a specified task-relevant memory base and (b) the participants' perception of the memory task. Three theoretical explanations of the effect of misleading post-event information are reinterpreted and reduced to one single core: individuals answer test questions while assuming the consistency of event and post-event information. The impact of such consistency assumptions (a) is demonstrated in a first experiment, where the usual misinformation effect obtained with the Loftus standard test procedure disappeared when the participants' consistency assumptions were destroyed prior to testing, and (b) manifests itself in a qualitative analysis of individual processing strategies for discrepancies between details. Experiment 2, employing methodological innovations suggested by IMP, examined the memory base and found no evidence for memory impairment or misattributions of post-event details to the witnessed scene. However, a follow-up study conducted four and a half months later revealed a strong tendency for such misattributions which might indicate long-term integration of information.     

Hypnotizability, preference for an imagic cognitive style, and memory creation in hypnosis

We sought to extend the finding (Laurence & Perry, 1983) that it is possible through hypnosis to create a pseudomemory of a specific event. Subjects were compared on their responses to a hypnotic suggestion. We also examined the relation between nonhypnotic measures (Preference for an Imagic Cognitive Style [PICS] test and the Tellegen Absorption Scale [TAS]) and response to the suggestion. Highly (45.45%) and moderately-highly (46.15%) susceptible subjects believed that the pseudomemory was veridical, but none of the low susceptible subjects did so. Together, hypnotic susceptibility, the PICS, and their interaction more strongly predicted pseudomemory creation than any of these main effects alone. Performance on the TAS was also related to the occurrence of pseudomemory, but this relation was redundant with performance on the other measures. These results point to the complexity of the variables involved in pseudomemory creation during hypnosis.     

Remembering (Short-Term) Memory: Oscillations of an Epistemic Thing

This paper provides an interpretation of Hans-J?rg Rheinberger’s notions of epistemic things and historical epistemology. I argue that Rheinberger’s approach articulates a unique contribution to current debates about integrated HPS, and I propose some modifications and extensions of this contribution. Drawing on examples from memory research, I show that Rheinberger is right to highlight a particular feature of many objects of empirical research (“epistemic things”)—especially in the contexts of exploratory experimentation—namely our lack of knowledge about them. I argue that this analysis needs to be supplemented with an account of what scientists do know, and in particular, how they are able to attribute rudimentary empirical contours to objects of research. These contours are closely connected to paradigmatic research designs, which in turn are tied to basic methodological rules for the exploration of the purported phenomena. I suggest that we engage with such rules in order to develop our own normative (epistemological) categories, and I tie this proposal to the idea of a methodological naturalism in philosophy of science.     

Memory for actions: Enactment and source memory

Enacting simple action phrases enhances item memory but may not enhance other aspects of memory. The present experiment examines the effects of enactment on source memory. During the study phase, participants performed some actions (subject-performed tasks, SPTs) and observed the experimenter perform other actions (experimenter-performed tasks, EPTs). One group performed the SPTs with eyes closed, one group with eyes open (the standard condition), and one group performed SPTs facing a mirror (EPT presentation was constant across groups). As expected, item memory was better for SPTs than for EPTs. More importantly, source memory for SPTs was affected by the amount of visual feedback. As predicted by the source-monitoring framework, source memory for SPTs decreased as the amount of visual feedback increased from none (eyes closed) to moderate (standard condition) to maximal (mirror condition). In addition, SPT encoding failed to increase source memory and in one condition actually decreased source memory, relative to EPT encoding. Thus, enactment dissociated item and source memory, enhancing the former but not the latter.     

Effects of suggestibility and hypnosis on accurate and distorted retrieval from memory

Research investigated the hypothesis inferred from the theorizing of Loftus that suggestibility is related to the tendency to incorporate incorrect information into memory when this information has been subtly introduced after the to-be-remembered events have occurred. Specifically, it was predicted that if level of suggestibility is theoretically relevant to subjects' acceptance of misleading information, then more subjects who are highly hypnotically suggestible than those with a low level of hypnotic suggestibility will incorporate the incorrect information into memory. Hypnotic as compared with waking instruction should enhance this distortion effect by providing a context of testing in which subjects are readily prone to respond positively to suggestions. Eight independent groups of 12 subjects were tested. Separate groups of subjects of high and low suggestibility were presented with misleading or neutral information about a wallet-snatching incident and tested for memory under either waking or hypnotic instruction. Analysis of subjects' memory distortions indicated that suggestibility plays a somewhat different role than has been argued previously. The magnitude of distortion that was observed varied according to the stimulus features that were studied, but hypnotic suggestibility was not associated with the distortion effect. Despite the fact that hypnosis did not enhance recall in any way, subjects were frequently confident that distorted memories recovered under hypnosis were accurate.     

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.     

Memory and consciousness: trace distinctiveness in memory retrievals

The aim of this article was to provide experimental evidence that classical dissociation between levels of consciousness associated with memory retrieval (i.e., implicit or explicit) can be explained in terms of task dependency and distinctiveness of traces. In our study phase, we manipulated the level of isolation (partial vs. global) of the memory trace by means of an isolation paradigm (isolated words among non-isolated words). We then tested these two types of isolation in a series of tasks of increasing complexity: a lexical decision task, a recognition task, and a free recall task. The main result of this study was that distinctiveness effects were observed as a function of the type of isolation (level of isolation) and the nature of the task. We concluded that trace distinctiveness improves subsequent access to the trace, while the level of trace distinctiveness also appears to determine the possibility of conscious or explicit retrieval.     

Memory Functioning Questionnaire: concurrent validity with memory performance and self-reported memory failures

Concurrent validity of factor scores from the Memory Functioning Questionnaire (MFQ; Gilewski, Zelinski, & Schaie, in press) with memory performance was investigated in 2 studies. Study 1 involved 198 adults aged 55-85; Study 2, 89 adults aged 50-87. After effects of depression, education, and health were partialed out, MFQ scores predicted performance on laboratory memory tests in Study 1 and performance on clinical memory tests and diaries of memory failures over 2 weeks in Study 2. Additional variance in predicting performance and failures recorded in diaries is accounted for by MFQ scores after partialing out subjects' responses to a yes-no question about whether they have memory problems. Results suggest that the MFQ has moderate concurrent validity with memory measures and is preferable to responses to a single question about memory self-perception in assessing memory complaints in normal adults.     

Memory span and short-term memory capacity: A developmental study

A memory span task involving series conditions comprised of several different types of material was administered to children from three grade levels (7–12 years of age). As expected, age differences were strongly affected by type of material, with two conditions (consonant letters, words) intended to restrict opportunities for chunking yielding age differences that were negligible, and one condition (consonant-vowel letters) constructed to maximize sequential probability yielding age differences that were large. This finding renders less plausible the popular notion that capacity increases with age, and suggests that age differences in memory span reflect chunking processes. Additional findings, which indicate that age differences in memory span are affected by method of presentation and stage of practice, suggest that these variables should be considered in studies aimed at estimating children's memory capacity.     

Incidental memory in dogs (Canis familiaris): adaptive behavioral solution at an unexpected memory test

Memory processing in nonhuman animals has been typically tested in situations where the animals are repeatedly trained to retrieve their memory trace, such as delayed matching to sample, serial probe recognition, etc. In contrast, how they utilize incidentally formed memory traces is not well investigated except in rodents. We examined whether domestic dogs could solve an unexpected test based on a single past experience. In Experiment 1, leashed dogs were led to 4 open, baited containers and allowed to eat from 2 of them (Exposure phase). After a walk outside for more than 10?min, during which time the containers were replaced with new identical ones, the dogs were unexpectedly returned to the site and unleashed for free exploration (test phase). Eleven out of 12 dogs first visited one of the containers from which they had not eaten. In Experiment 2, two containers had food in them, one had a nonedible object, and the last one was empty. Dogs visited all 4 containers and were allowed to eat one of the food rewards in the Exposure phase. In the test phase, unleashed dogs first visited the previously baited container from which they had not eaten significantly more often than chance. These results demonstrate that in an unexpected, test dogs may retrieve “what” and “where” information about seen (now invisible) items from incidental memory formed during a single past experience.     

Memory strength and the decision process in recognition memory

We investigated the role that memory strength plays in the decision process by examining the extent to which strength is used as a cue to dynamically modify recognition criteria. The study list consisted of strong and weak items, with strength a function of study duration or repetition. The recognition test list was divided into two consecutive blocks; strong items appeared in one block, weak items in the other. If the change in item strength across blocks leads to a shift in criterion, the false alarm rate should change accordingly. In four experiments, the false alarm rates did not change across blocks, even when the difference between the strong and the weak items was magnified and marked with semantic cues. However, the strength of the items in the first test block affected the false alarm rate. Thus, strength cues influence initial criterion placement but fail to induce criterion shifts following permanent and even dramatic changes in item strength. These null findings are contrasted with those in a fifth experiment, in which accuracy feedback produced dynamic criterion shifts.     

Memory and memory confidence in obsessive-compulsive disorder

Pathological doubt, often found in individuals with obsessive-compulsive disorder (OCD), has been theoretically linked to memory deficits, but empirical evidence for such deficits has been mixed. In contrast, many studies suggest that individuals with OCD have low confidence in their memories. The present study aimed to build upon previous research by measuring memory accuracy and confidence in OCD using ecologically valid, idiographically-selected stimuli. Individuals with OCD (OCs), anxious controls (ACs), and nonanxious controls (NACs) were exposed to a set of objects that the OCs had identified as safe, unsafe, or neutral. Participants were then asked to recall as many objects as possible and to rate their confidence in each memory. This process was repeated 6 times, using the same stimuli for each trial. Contrary to hypothesis, no group differences emerged in memory accuracy. However, OCs' memory confidence for unsafe objects showed a progressive decline over repeated trials. This pattern was not observed among NACs or ACs. Furthermore, OCs with primary checking reported lower confidence in long-term memory than did OCs without primary checking. These results suggest that when OCs are repeatedly exposed to threat-related stimuli (such as repeated checking), their level of confidence in remembering these stimuli paradoxically decreases.     

Memory complaint and memory performance in the depressed elderly

Depressed and nondepressed elderly subjects recruited in the context of a large epidemiological study of health were compared on measures of self-reported memory disturbance and an objective index of memory performance (free recall). Three groups were studied including (a) subjects meeting Research Diagnostic Criteria (RDC) for major depression, (b) subjects with high levels of self-reported depressive symptoms who did not meet RDC for major depression, and (c) subjects with low levels of self-reported depressive symptoms. Subjects with high depression symptom levels reported significantly higher levels of memory complaint than did subjects with low symptom levels. However, there were no differences in self-reported memory disturbance as a function of depression diagnosis. Further, there were no significant differences between groups on the free-recall measure, either as a function of symptom level or diagnosis. It is argued that symptom severity rather than diagnosis of depression is important in determining impairment in depressed elderly people.     

Memory anxiety and memory performance in adulthood

The present study examined the contribution of general and domain-specific anxiety to the prediction of memory performance in a sample of 350 young, middle-aged and old adults. In a preliminary stage of this investigation, psychometric analyses revealed that the predictive validity of the Anxiety scale of the Metamemory in Adulthood questionnaire, used to assess memory-related anxiety, could be improved by using an abbreviated version of the scale. This Memory Anxiety subscale predicted level of state anxiety experienced by middle-aged and older subjects in anticipation of a memory-demanding task. It was superior to the general state measures in predicting actual memory performance, but only for the oldest age group. Results thus provide support for domain- and age-specificity in the assessment of anxiety performance relationships.