This study aims to analyze implicit and explicit memory performance as a function of cognitive reserve (CR) in a healthy control group (N = 39) and a mild cognitive impairment (MCI) group (N = 37). Both groups were subdivided into high and low cognitive reserve, and were asked to complete an explicit and implicit associative recognition tasks. The results showed that the control group was able to learn both tasks (η2 = .19, p < .0001), and the high CR group fared better (η2 = .06, p < .05). The MCI sample, conversely, was unable to learn the implicit relationship, and showed very little learning on the explicit association task. Participants diagnosed with MCI showed little plasticity in learning associations regardless of CR (η2 = .12, p < .01).

This study evaluated the perceptual priming in fourth grade primary school children using a word-fragment completion task. The children were classified into two categories according to their reading speed: high and low. Using several sub-scales of the WISC-IV, their working memory was measured, and their total IQ was estimated, in order to control for their effects on priming. The statistical analyses showed that children with high reading speed were significantly better at word-fragment completion and showed greater priming (p < .01); in other words, the prior processing of the words from which the fragments came produced a greater benefit in the performance of the word-fragment completion task. A regression model was developed to explain reading speed based on the following variables: perceptual priming, working memory and percentage of completed fragments belonging to words not previously processed (adjusted R 2 = 0.64).

The objective of the current study was to compare the performance of schizophrenic patients and normal controls on implicit memory tests. Two neuropsychological tasks were administered to 29 patients and normal participant samples. The implicit tests were: Word fragment completion and Word production from semantic categories. The priming score was the variable of interest. Priming effects are obtained in normal subjects and schizophrenia patients, regardless of the implicit test used. However, a dissociation in priming between normal and patient groups was observed, depending on the test used. For word fragment test, priming was identical between the two groups. However, for word production, priming obtained in schizophrenics was lower than priming in normal controls. Results confirm a dissociation effect in implicit memory tests. These results could be explained in the context of the Roediger and Blaxton (1987) distinction between data-driven and conceptually-driven processing. This evidence suggests that a complete neuropsychological assessment of memory in schizophrenia should include different kinds of implicit memory tests (procedural, perceptual, and conceptual tasks).

Previous studies had revealed no specific effect under haloperidol (typical) and risperidone (atypical) neuroleptic (NLP) treatments for schizophrenia (SZ) on a variety of neurocognitive functions relying on the dopaminergic meso-cortico-limbic system (Rémillard et al., 2005, 2008). Considering the different affinities of D2 dopamine receptors for typical and atypical NLPs, these drugs may differentially affect the functions of the striatum, a determinant brain structure involved in procedural learning. The influence of risperidone (2–6 mg) and haloperidol (2–40 mg) on a nonmotor procedural task involving semantically related pairs of words with inverted letters was investigated in this double-blind study. The performance of 26 patients with SZ, randomly assigned to risperidone or haloperidol, was compared to that of 18 healthy controls at baseline, 3, 6, and 12 months. Results revealed that all patients with SZ exhibited slower reading speed of the word pairs than healthy controls at all assessment periods. In addition, procedural learning – characterized as a significant decrease in the time taken to read aloud the target word pairs – was more impaired in the haloperidol- than in the risperidone-treated group at all assessment periods. Healthy controls showed steady improvement in reading speed over the 12 months of the study, in contrast to SZ patients, who reached a plateau in their capacity to improve mirror-reading skill over time. However, all SZ participants in the study showed near normal learning profiles from exposure to semantic associations embedded in the procedural memory task, providing evidence for the preservation of associative connections in the semantic network of these patients. The observed impairment in procedural learning in SZ may thus reflect, at least in part, the influence of neuroleptic medication on striatal functions. (JINS, 2010, 16, 148–156.)

Errorless learning is an intervention that benefits memory performance in healthy older adults and a variety of clinical populations. A limitation of the errorless learning technique is that it is passive and does not involve elaborative processing. We report two studies investigating the added benefits of elaborative, self-generated learning to the errorless learning advantage. We also explored the mnemonic mechanisms of the errorless learning advantage. In both studies, older adults and individuals with amnestic mild cognitive impairment (aMCI) completed four encoding conditions representing the crossing of errorless/errorful learning and self-generated/experimenter-provided learning. Self-generation enhanced the errorless learning benefit in cued recall and cued recognition, but not in free recall or item recognition. An errorless learning advantage was observed for priming of target words, and this effect was amplified for participants with aMCI after self-generated learning. Moreover, the aMCI group showed significant priming of prior self-generated errors. These results demonstrate that self-generation enhances the errorless learning advantage when study and test conditions match. The data also support the argument that errorless learning eliminates the misleading implicit influence of prior errors, as well as the need for explicit memory processes to distinguish targets from errors. (JINS, 2009, 15, 704–716.)

Amnesic patients often exhibit spared priming effects on implicit memory tests despite poor explicit memory. In previous research, we found normal auditory priming in amnesic patients on a task in which the magnitude of priming in control subjects was independent of whether speaker's voice was same or different at study and test, and found impaired voice-specific priming on a task in which priming in control subjects is higher when speaker's voice is the same at study and test than when it is different. The present experiments provide further evidence of spared auditory priming in amnesia, demonstrate that normal priming effects are not an artifact of low levels of baseline performance, and provide suggestive evidence that amnesic patients can exhibit voice-specific priming when experimental conditions do not require them to interactively bind together word and voice information. (JINS, 1995, I, 434–442.)

There have been few studies of psychogenic amnesia based on a cognitive or neuropsychological framework. In the present study, a patient with acute onset of profound psychogenic retrograde amnesia was examined. Although her performance on neuropsychological tasks revealed intact anterograde memory, language functioning, visuospatial and constructional skills, and mental speed and flexibility, she displayed severe impairments on a variety of retrograde memory tasks. Furthermore, initial observations revealed inconsistencies between the patient’s recall of semantic knowledge on direct questioning and her ability to demonstrate the use of this knowledge on indirect tasks. To test this formally, we devised an indirect remote knowledge task to examine a possible dissociation between explicit and implicit memory. Two healthy subjects matched for age, gender, education, occupation, and estimated IQ were also tested. As predicted, the findings demonstrate implicit knowledge despite impaired explicit recall for the same material. (JINS, 1996, 2, 146–158.)

This study explored the nature of the relationship between attention available at learning and subsequent implicit and explicit memory performance. One hundred neurologically normal subjects rated their liking of target words on a five-point scale. Half of the subjects completed the word-rating task in a full attention condition and the other half performed the task in a divided attention condition. Following administration of the word-rating task, all subjects completed five memory tests, three implicit (category association, tachistoscopic identification, and perceptual clarification) and two explicit (semantic-cued recall and graphemic-cucd recall), each bearing on a different subset of the list of previously presented target words. The results revealed that subjects in the divided attention condition performed significantly more poorly than subjects in the full attention condition on the explicit memory measures. In contrast, there were no significant group differences in performance on the implicit memory measures. These findings suggest that the attention to an episode that is necessary to produce later explicit memory may differ from that necessary to produce unconscious influences. The relationship between implicit memory, neurologic injury, and automatic processes is discussed. (JINS, 1996, 2, 111–125.)

There is evidence that the prevention of errors during learning might be helpful in improving an impaired memory performance, both in amnesia as well as in normal age-related memory decline. Although errorless learning is a promising technique for use in rehabilitation practice, the underlying mechanisms are unclear. That is, it has been suggested that the beneficial effects of errorless learning operate through implicit memory, whereas others implicate that it is explicit memory that is responsible for the enhanced memory performance after errorless learning. The current study examined the contribution of implicit and explicit memory function to the memory performance after errorless and errorful learning using the process-dissociation procedure. A group of young adults (N = 40) was compared to a matched group of older individuals (N = 40) on a spatial memory task (i.e., learning the locations of everyday objects in a room). The results clearly show age-related decline in explicit spatial memory, while implicit spatial memory was unaffected. Furthermore, the young group benefited from errorless learning compared to errorful learning, while the older group did not show a difference between the two learning conditions. Also, it was found that the effects of errorful learning were related to explicit memory function, and not implicit processing, corroborating and extending recent findings. (JINS, 2005, 11, 144–151.)

This study examined the distinction between identification and production processes in repetition priming for 16 patients with Alzheimer's disease (AD) and 16 healthy old control participants (NC). Words were read in three study phases. In three test phases, participants (1) reread studied words, along with unstudied words, in a word-naming task (identification priming); (2) completed 3-letter stems of studied and unstudied words into words in a word-stem completion task (production priming); and (3) answered yes or no to having read studied and unstudied words in a recognition task (explicit memory). Explicit memory and word-stem completion priming were impaired in the AD group compared to the NC group. After correcting for baseline slowing, word-naming priming magnitude did not differ between the groups. The results suggest that the distinction between production and identification processes has promise for explaining the pattern of preservation and failure of repetition priming in AD. (JINS, 2001, 7, 785–794.)