Scanning and immediate memory in serial adding

Abstract

Performance on a paced serial addition task (PSAT) under variable pacing and stimulus duration conditions was compared with that on two related tasks, whose basic operations were respectively integration (in this instance, adding) and immediate memory, each a component operation of the PSAT. Results showed that none of the PSAT performance trends appeared on the first of these related tasks, but all were significant on the second. These support a hypothesis (Sampson, 1958) that the stimulus duration effect reflects an immediate memory disturbance, and show that the integration component can account for none of the trends. Consideration of the nature of the pacing effect suggested that a central scanning operation may also be important.