1. ¹Laboratoire de Psychologie Sociale de la Cognition (LAPSCO - UMR 6024 CNRS), Universite Blaise Pascal, Clermont-Ferrand Cedex, France
2. ²INSERM U405, Clinique psychiatrique, Hopital civil, Strasbourg Cedex, France

Correspondence: Dr M Izaute, Laboratoire de Psychologie Sociale de la Cognition (LAPSCO - UMR 6024 CNRS), Universite Blaise Pascal, 34, Avenue Carnot 63037, Clermont-Ferrand Cedex, France. Tel: +33 04 73 40 62 55; Fax: +33 04 73 40 64 82; E-mail: Marie.Izaute@srvpsy.univ-bpclermont.fr

Received 19 December 2003; Revised 1 July 2004; Accepted 13 July 2004; Published online 13 October 2004.

Abstract

We investigated the effects of lorazepam, a benzodiazepine, on the allocation of study time, memory, and judgment of learning, in a cognitive task where the repetition of word presentation was manipulated. The aim was to assess whether lorazepam would affect the learning processes and/or whether the participants would be aware of the amnesic difficulty. A total of 30 healthy volunteers participated in the study, 15 of whom received a capsule containing the lorazepam drug (0.038 mg/kg) and 15 a placebo capsule. First, the accuracy of delayed judgments of learning (JOL) was measured in both groups. For the JOL ratings, results showed that all the participants benefited from word repetition. Although the overall performance was lower in the lorazepam than in the placebo group, the accuracy of the JOL ratings was preserved by the drug. Second, all the participants benefited from the repetition of learning, although the performances of the lorazepam-treated subjects remained lower than those of the placebo participants. The repetition of learning had an effect on JOL in both groups. Finally, the time spent learning each (allocation study time) pair of words was measured. For the placebo group, results revealed that study time decreased significantly with the frequency of presentation. For the lorazepam group, no effect of presentation frequency was found. Overall, our findings suggest that the lorazepam drug has a differential effect on the monitoring and the control processes involved in a learning task. The implications of these findings are discussed within the theoretical framework of metacognition.