Status of recognition memory in amnesia.

The contribution of fluency and recollection to amnesics' recognition memory was examined by comparing performance in a condition in which patients were asked to include items presented in the 1st phase of the experiment with performance in a condition in which they were asked to exclude those same items. The performance of amnesics, unlike that of controls, did not significantly differ as a function of task instruction. Use of L. L. Jacoby's (1991) subtraction procedure indicated that amnesics were much less likely to use conscious recollection as a basis for recognition judgments. However, amnesics were as likely as controls to base their recognition judgment on the fluency with which an item came to mind. Discrepancies in previously reported recognition results with amnesics may reflect the variable contribution of fluency and recollection to recognition memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pragmatics of measuring recognition memory: Applications to dementia and amnesia.

This article has two purposes. The first is to describe four theoretical models of yes-no recognition memory and present their associated measures of discrimination and response bias. These models are then applied to a set of data from normal subjects to determine which pairs of discrimination and bias indices show independence between discrimination and bias. The second purpose is to use the indices from the acceptable models to characterize recognition memory deficits in dementia and amnesia. Young normal subjects, Alzheimer's disease patients, and parkinsonian dementia patients were tested with picture recognition tasks with repeated study–test trials. Huntington's disease patients, mixed etiology amnesics, and age-matched normals were tested by Butters, Wolfe, Martone, Granholm, and Cermak (1985) using the same paradigm with word stimuli. Three major points are emphasized. First, any index of recognition memory performance assumes an underlying model. Second, even acceptable models can lead to different conclusions about patterns of learning and forgetting. Third, efforts to characterize and ameliorate abnormal memory should address both discrimination and bias deficits. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-term memory in amnesia: Cued recall, recognition memory, and confidence ratings.

We explored what kind of information is acquired when amnesic patients are able to exhibit significant retention on tests of cued recall and recognition memory. Amnesic patients and control subjects attempted to learn sets of sentences. Memory for the last word in each sentence was tested after 1 hr in the case of the amnesic patients, or after 1 to 2 weeks in the case of (delayed) control subjects. Amnesic patients and (delayed) control subjects performed at similar levels on tests of cued recall and recognition memory. Amnesic patients were just as confident of their correct answers as were control subjects. Moreover, amnesic patients were no more disadvantaged than control subjects when they were cued indirectly by presenting paraphrases of the original sentences. These findings demonstrate that the residual knowledge retained by amnesic patients can be as flexible, as accessible to indirect cues, and as available to awareness as the knowledge retained by (delayed) control subjects. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recall and recognition memory during posthypnotic amnesia: A failure to confirm the disrupted-search hypothesis and the memory disorganization hypothesis.

Tested hypotheses that posthypnotic amnesia is characterized by a disruption in the memory search process and, more generally, by disorganization in memory retrieval. 141 undergraduates were administered the Stanford Hypnotic Susceptibility Scales, Forms B and C. Amnesia was assessed by the usual recall criterion and by a batch recognition-testing procedure. The disrupted-search hypothesis, tested by comparing the effects of the amnesia suggestion on recall and recognition, was not supported. The use of recognition items, rank ordered by Ss according to their judgment of order of administration, furnished data to test the memory disorganization hypothesis. In support of this hypothesis, analyses of the temporal rankings of recognized items revealed greater disorganization in the memory of Ss who were initially amnesic by recall criteria than those who were partially amnesic or nonamnesic. Nevertheless, other findings, including the fact that fewer than 50% of the initially amnesic Ss showed disorganized recognition and that the disorganization effect during recall was weak and inconsistent, call into question the explanatory power of this hypothesis. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Episodic and semantic memory in posthypnotic amnesia: A reevaluation.

J. F. Kihlstrom (see record 1980-11245-001) hypothesized that posthypnotic amnesia involved a dissociation between episodic and semantic components of memory. The present study tested an alternative hypothesis that Kihlstrom's findings resulted from experimental demands conveyed by the wording of the amnesia suggestion he employed. It was hypothesized that hypnotically amnesic Ss would show performance deficits on semantic and episodic memory tasks if expectations for such deficits were subtly conveyed to them. Using 2 treatment conditions, 60 undergraduates were divided into susceptibility groups. Condition 1 replicated Kihlstrom's experiment; in Condition 2, Ss were given an alternative hypnotic suggestion. It was found that Ss could be induced to show only episodic impairments (thereby replicating Kihlstrom) or both episodic and semantic impairments (contrary to Kihlstrom) by subtly varying the wording of amnesia suggestions. Findings are inconsistent with a dissociation hypothesis. Instead, they support the notion that hypnotic amnesia is a strategic enactment strongly influenced by expectations generated in the amnesia testing situation. (34 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact baseline performance and priming in amnesia: Reply to Ostergaard and Jernigan.

In their comment on the article by S. B. Hamann et al (see record 1995-14158-001), A. L. Ostergaard and T. L. Jernigan (see PA, Vol 83:23639) reaffirmed their position that baseline perceptual identification performance and priming are impaired in amnesia. They also suggested certain shortcomings in the experiments of Hamann et al, who found normal baseline performance and normal priming in amnesia across a wide range of performance accuracies. In reply, the authors of this article suggest that the position of Ostergaard and Jernigan rests on selective consideration of data, inaccurate assumptions concerning 1 patient's priming performance (A.B.), and debatable concerns about the masking stimuli, ceiling effects, and presentation time of study items that were used. In addition, the authors of the present article suggest that Ostergaard and Jernigan have based their own experimental work on a task and test method that may not be optimal for studying priming. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Emotional perception and memory in amnesia.

The authors examined whether perception of emotional stimuli is normal in amnesia and whether emotional arousal has the same enhancing effect on memory in amnesic patients as it has in healthy controls. Forty standardized color pictures were presented while participants rated each picture according to emotional intensity (arousal) and pleasantness (valence). An immediate free-recall test was given for the pictures, followed by a yes-no recognition test. Arousal and valence ratings were highly similar among the amnesic patients and controls. Emotional arousal (regardless of valence) enhanced both recall and recognition of the pictures, and this enhancement was proportional for amnesic patients and controls. Results suggest that emotional perception and the enhancing effect of emotional arousal on memory are intact in amnesia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The relationship between recall and recognition in amnesia: Effects of matching recognition between patients with amnesia and controls.

To examine the relationship between recall and recognition memory in amnesia, the authors conducted 2 experiments in which recognition memory was equated between patients with amnesia and control participants. It was then determined whether recall was also similar across groups. In Experiment 1, recognition was equated by providing amnesic patients with additional study exposures; in Experiment 2, recognition was equated by testing controls following a longer delay. These different methods of equating recognition across groups led to divergent results because amnesic patients' recall performance was lower than controls' recall performance in Experiment 1 but not in Experiment 2. These findings are accounted for by considering the differential contribution of recollection and familiarity to the performance of amnesic patients and controls in the 2 experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A neuropsychological study of fact memory and source amnesia.

We investigated the ability of amnesic patients to learn new facts (e.g., Angel Falls is located in Venezuela) and also to remember where and when the facts were learned (i.e., source memory). To assess the susceptibility of fact and source memory to retrograde amnesia, patients prescribed electroconvulsive therapy were presented facts prior to the first treatment and were tested after their second treatment. All amnesic patients exhibited marked fact memory impairment. In addition, some amnesic patients exhibited source amnesia (i.e., they recalled a few facts but then could not remember where or when those facts had been learned). Source amnesia was unrelated to the severity of the memory deficit itself, because patients who exhibited source amnesia recalled as many facts as the patients who did not. These results show that the deficit in amnesia includes an impairment in acquiring and retaining new facts. Source amnesia can also occur, but it is dissociable from impaired recall and recognition and appears to reflect difficulty in remembering the specific context in which information is acquired. The findings are discussed in terms of their significance for how memory is organized. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Retrograde amnesia for discriminated taste aversions: A memory deficit.

Trained 50 male Sprague-Dawley rats in a saccharin-anise discriminated taste aversion paradigm. Saline or pentylenetetrazol (metrazol), an amnesia agent, was administered either within or after the CS-UCS interval. Retrograde amnesia (RA) resulted in both cases, but was stronger when induced after the UCS. Due to the nature of the discriminated-avoidance paradigm used, the RA could not be explained in terms of the punishing effects of the RA treatment or general disinhibition. Data indicate that an amnesic treatment causes a memory deficit, at least part of which is due to the disruption of the CS trace. (20 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

False memories and statistical design theory: Comment on Miller and Wolford (1999) and Roediger and McDermott (1999).

In an analysis of H. L. Roediger and K. B. McDermott's (see record 1995-42833-001) false-memory paradigm, M. B. Miller and G. L. Wolford (see record 1999-13930-007) argued that falsely recognized items occur because a bias toward calling such items "old" is created by their membership in a studied category. This interpretation was contested by Roediger and McDermott (see record 2000-15248-006). The authors of this article approach this issue as a statistical decision problem and observe that an explanation of false memory based on stored strengths and one based on decision process can have identical implications for data. Problems with equivalent formal models of this type can frequently be resolved by looking at the effects of other variables on the fitted estimates. The authors illustrate this analysis by examining the effects of presentation duration on the parameter estimates produced by models that instantiate the 2 explanations. Although the question remains open, the storage-based interpretation was found to be somewhat more plausible. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Working memory and skill acquisition: Reply to Halpern.

D. F. Halpern (see record 1991-00321-001) argues that our observations of subjects acquiring a complex problem-solving skill "cannot be used to differentiate between single-workspace and distributed processing models of working memory." In this reply, we attempt to clarify the implications of our results for working memory models, and we discuss the nature of distributed-capacity models of working memory. It is difficult to discriminate the set of possible flexible single-workspace models from distributed models. Our results do disconfirm major assumptions typical of single-workspace models and illustrate the kind of flexibility needed in a model of working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of indirect memory tests to assess malingered amnesia: A study of metamemory.

Many techniques have been suggested for identifying criminal suspects who are simulating amnesia for events surrounding a crime. The present research focuses on indirect memory tests as a potential means of discriminating between those who genuinely suffer from amnesia and those who are simulating. Ss studied a list of words and subsequently performed either a word completion or a fragment completion task. Under normal indirect test instructions, typical priming effects were observed. When Ss were motivated to simulate amnesia for the list, target completion rates were consistently, and sometimes reliably, below baseline completion rates. This finding is contrary to the performance of genuine amnesics, whose performance on indirect tests typically mirrors that of normal Ss. Indirect tests may prove useful in discriminating genuine and simulating amnesics. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceptual and conceptual memory processes in global amnesia.

To determine whether global amnesia reflects a selective deficit in conceptual processing, amnesic and control Ss performed 4 memory tasks that varied processing and retrieval requirements. A study-phase modality (auditory/visual) manipulation validated the nature of processing (perceptual and conceptual) engaged by each task. Amnesic patients were impaired on perceptual and conceptual explicit memory tasks (word-fragment and word-associate cued recall) and were intact on perceptual and conceptual implicit memory tasks (word-fragment completion and word association). These results are consistent with the view that limbic-diencephalic structures damaged in amnesia mediate, in part, processes typically engaged during explicit retrieval. The results are inconsistent, however, with the characterization of that deficit as being one of conceptual processing per se. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Doubts concerning primacy in rats' nonspatial recognition memory: Reply to Gaffan and Gaffan (1992).

E. A. Gaffan and D. Gaffan (see record 1992-37974-001) drew attention to an alarming lack of variability in a previous report (P. Reed et al; see record 1991-11847-001) of primacy and recency in recognition memory for nonspatial lists in rats. Their analysis, and the doubts raised by it, are accepted in the present article. Further analysis of the original data suggests that the low variability in the Reed et al data may have stemmed partly from experimenter effects. Equivalent analyses of other experiments conducted using the same apparatus and the same kinds of stimuli showed variances in line with a priori expectation. A new experiment modeled on the original one (but differing in some respects) showed recency but no primacy. It is concluded that the previous report of Reed et al should, for the present, be regarded as potentially flawed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transient global amnesia: memory and metamemory

Twenty patients (mean age 64 years) with a previous episode of transient global amnesia (TGA) were examined to assess the functioning of objective memory (by using the Randt Memory Test), the metamemory capacities (Sehulster Memory Scale), the residual level of retrograde amnesia (Questionnaire of Remote Events), and the level of depression (Geriatric Depression Scale). Patients with residual retrograde amnesia scored significantly lower than non-amnesic ones on indices of both short-term and long-term memory, and for one of three main metamemory components, namely self-rating of memory functioning through comparison with memory functioning of peers (Set3). Age, time interval from TGA attack and TGA duration did not prove to influence memory and metamemory scores. Retrograde amnesia and depression were rather substantially associated (1/5), and this association was found to negatively influence nearly all memory and metamemory scores. Depression level showed a positive correlation with short-term memory functioning in non-amnesics. The different pattern and strength of the relationships between metamemory components and objective memory dimensions observed in amnesics and non-amnesics indicate that metamemory evaluations are more closely related to memory functioning in amnesics than in non-amnesics.     

Midazolam amnesia and conceptual processing in implicit memory.

Prominent theories of implicit memory (D. Schacter, B. Church, & J. Treadwell, 1994) emphasize the dominant role of perceptual processing in mediating priming on perceptual implicit memory tests. Examinations of the effects of conceptual processing on perceptual implicit memory tests have produced ambiguous results. Although a number of investigations (e.g., J. Toth & R. Hunt, 1990) have demonstrated that variations in conceptual processing affect priming on perceptual implicit memory tests, these effects may arise because of the contaminating effects of explicit memory. The current experiment examined this controversy using midazolam, a benzodiazepine that produces a dense, albeit temporary, anterograde amnesia when injected prior to study. The experiment examined whether the effects of generation found on the implicit memory test of perceptual identification were affected by a midazolam injection prior to study. Results demonstrated that midazolam substantially diminished generation effects in free and cued recall, as well as overall performance on these tests, but had no detectable effect on the generation effect in perceptual identification. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Intact and impaired conceptual memory processes in amnesia.

To examine the status of conceptual memory processes in amnesia, a conceptual memory task with implicit or explicit task instructions was given to amnesic and control groups. After studying a list of category exemplars, participants saw category labels and were asked to generate as many exemplars as possible (an implicit memory task) or to generate exemplars that had been in the prior study list (an explicit memory task). After incidental deep or shallow encoding of exemplars, amnesic patients showed normal implicit memory performance (priming), a normal levels-of-processing effect on priming, and impaired explicit memory performance. After intentional encoding of exemplars, amnesic patients showed impaired implicit and explicit memory performance. Results suggest that although amnesic patients can show impairments on implicit and explicit conceptual memory tasks, their deficit does not generalize to all conceptual memory tasks. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling hippocampal and neocortical contributions to recognition memory: A complementary-learning-systems approach.

The authors present a computational neural-network model of how the hippocampus and medial temporal lobe cortex (MTLC) contribute to recognition memory. The hippocampal component contributes by recalling studied details. The MTLC component cannot support recall, but one can extract a scalar familiarity signal from MTLC that tracks how well a test item matches studied items. The authors present simulations that establish key differences in the operating characteristics of the hippocampal-recall and MTLC-familiarity signals and identify several manipulations (e.g., target-lure similarity, interference) that differentially affect the 2 signals. They also use the model to address the stochastic relationship between recall and familiarity and the effects of partial versus complete hippocampal lesions on recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)