Effects of the amnesic drug lorazepam on complete and partial information retrieval and monitoring accuracy.

rationaleIn Koriat's accessibility model (Koriat, Psychol Rev, 100:609-639, 1993; Koriat, J Exp Psychol Gen, 124:311-333, 1995), when a person fails to recall a required target, he or she can nevertheless provide some partial information about the target. Moreover, individuals are able to provide feeling-of-knowing (FOK) judgments about the availability of the target in memory. The cues for the FOK evaluations reside in the products of the retrieval process itself. It was shown that the benzodiazepine lorazepam drug induces some impairment of memory.

objectivesThe effects of the amnesic benzodiazepine lorazepam on the total and partial recall of recently learned material and on FOK ratings were investigated in healthy volunteers.

methodsTwenty-eight healthy volunteers participated in the study: 14 of these received a capsule containing lorazepam (0.038 mg/kg) and 14 a placebo capsule. The material to be learned consisted of four-letter nonsense tetragrams with each letter providing partial information with regard to the four-letter target (Koriat, Psychol Rev, 100:609-639, 1993).

resultsThe number of incorrect letters reported was higher for the lorazepam than for the placebo condition. The FOK magnitude was higher for the placebo participants than for the lorazepam participants. The predictive value of FOK for recognition was preserved by the drug.

conclusionWhen studying four-letter nonsense letter strings, lorazepam participants present an impairment of episodic short-term memory and the drug has an effect on FOK estimates but not on the predictive accuracy of the FOK. The accessibility hypothesis of FOK was confirmed in this study and seems to retain some validity even under the effect of an amnesic drug.