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The effects of lorazepam (0.026 or 0.038 mg/kg), a benzodiazepine, and of a placebo on metamemory, i.e. knowledge about one's own memory capabilities, were investigated in 36 healthy volunteers. Accuracy of confidence levels (CL) in the correctness of recalled answers and accuracy of feeling of knowing (FOK) the answers when recall fails were measured using a sentence memory task assessing episodic memory and a task consisting of general information questions and assessing semantic memory. Lorazepam impaired episodic memory. Unexpectedly, it also impaired performance in both the recall and recognition phases of the task assessing semantic memory, suggesting that it decreased the ability to distinguish between correct and incorrect information. In episodic memory, lorazepam 0.038 mg/kg-treated subjects exhibited an impaired CL accuracy, compared to placebo-treated subjects, and their FOK accuracy was at chance. In semantic memory, their overall CL and FOK accuracy was apparently spared. However, these subjects selectively overestimated their CL judgements for incorrect answers; moreover, secondary analyses showed that FOK accuracy for a subset of low-accuracy items was virtually nil. These results suggest that lorazepam impairs metamemory for both episodic and semantic memory.

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The aim of this study was to investigate the effects of aging on inhibitory processes and attentional resources in a long-lasting Go/No-Go sustained attention task using the event-related potential (ERP) technique. In line with recent studies, our results showed that older adults were able to maintain sustained attention performance throughout the duration of the task, whereas younger subjects exhibited a vigilance decrement. Regarding ERP results, older adults had larger P2 and Go-P3 amplitudes, components related to resource allocation, suggesting that the older subjects invested more resources in task performance. In addition, the No-Go P3 component, related to inhibitory processes, was more frontally distributed in older than in younger participants. This age-related frontal scalp overrecruitment may have played a compensatory role, enabling older subjects to perform better than younger subjects throughout the duration of the task.

Patients were impaired in subjectively assessing the correctness of their knowledge, and their behavior was less determined by subjective experience than that of normal subjects. The patients' intact sensitivity to incentives has implications for cognitive remediation.

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Metamemory awareness refers to the ability to monitor and control how well information is processed depending on the loads and needs of the task at hand. There is some evidence that metamemory functions are impaired in schizophrenia at the time of memory retrieval. This study investigated whether patients with schizophrenia exhibit metamemory abnormalities during the encoding of new information. The frequency of item presentation was varied. Both memory control and memory monitoring were assessed using study-time allocation and Judgments of Learning (JOL), respectively. Repeated items were recalled better by both groups, but memory performance was lower in patients than controls. Patients' behavior patterns were abnormal in terms of the study-time allocated for each item according to presentation frequency. Patients' JOLs were lower than those of controls but remained sensitive to item repetition. Patients' predictive values on memory accuracy were no different to those measured in controls. In addition, none of the patients reported using efficient strategies to help memorize target items. The results show a dissociation between memory control, which was impaired, and memory monitoring, which was spared, in patients with schizophrenia during encoding of new information.