NONVERBAL WORKING-MEMORY OF HUMANS AND MONKEYS - REHEARSAL IN THE SKETCHPAD

Investigations of working memory tend to focus on the retention of ver bal information. The present experiments were designed to characterize the active maintenance rehearsal process used in the retention of vis uospatial information. Rhesus monkeys (Macaca mulatta; N = 6) were tes ted as well as humans (total N = 90) because these nonhuman primates h ave excellent visual working memory but, unlike humans, cannot verball y recode the stimuli to employ verbal rehearsal mechanisms. A series o f experiments was conducted using a distractor-task paradigm, a direct ed forgetting procedure, and a dual-task paradigm. No evidence was fou nd for an active maintenance process for either species. Rather, it ap pears that information is maintained in the visuospatial sketchpad wit hout active rehearsal.