Changes of Pupil Size and Rehearsal Strategies in a Short-Term Memory Task

Abstract

Twelve subjects learned lists consisting of 3 groups of 4 items each drawn from vocabularies of digits, colour names or boys' names. There were two conditions of recall, total or partial, and two retention intervals, 3 and 7 sec. A view of the function of rehearsal suggests that rehearsal for total recall should be more intense than for partial recall, but only with a brief retention interval. Measurements of pupillary diameter confirm this prediction. Conditions under which pupillary measurements can serve to test theories of psychological processes are discussed.