Recognition memory in amnesia: effects of relaxing response criteria.

In two experiments, using the remember/know paradigm, we examined whether recognition memory in amnesic patients can be improved by instructing patients to relax their response criterion. Experiment 1 was modeled after a study by Dorfman, Kihlstrom, Cork, and Misiaszek (1995), in which direct instructions to respond more leniently led to an increase in recognition accuracy in patients with ECT-induced amnesia. We failed to extend this finding to patients with global amnesia, but the manipulation was unsuccessful in control subjects as well. In Experiment 2, response criterion was manipulated indirectly by providing information about the alleged base rate of study items on the recognition test. This manipulation led to a criterion shift in control subjects and enhanced discriminability in amnesic patients. Analysis of "remember" and "know" responses suggests that improved accuracy in amnesia was associated with enhanced familiarity-based recognition.