Processing depth, elaboration of encoding, memory stores, and expended processing capacity.

Abstract

The divided attention technique introduced by W. A. Johnston was used to assess effects of several factors on expended processing capacity, which was indexed by slowing of simple reaction time during concurrent processing of other information. Expended processing capacity was greater when information was retrieved from secondary memory than from primary memory; when processing was of a deep, semantic nature than when it was shallow and physical; and it was greater when processing was more elaborate. The evidence thus suggests that expended processing capacity accurately reflects important aspects of memorial functioning. The relevance of these findings to limited capacity theories is discussed. The experiments reported in this article are concerned with effects of several variables (memory store, depth of processing, and elaboration of processing) on expended processing capacity. There are valid theoretical reasons for investigating these issues: If people have limited processing capacity, then it is obviously of importance to establish relative demands on that processing capacity imposed by different processing activities. To obviate semantic confusion, some of key concepts referred to in this article will be defined at this point. We follow Johnston and Heinz (1978) in defining processing capacity as the limited pool of energy, resources, or fuel by which some cognitive operations or processes are mobilized and maintained (p. 422). We assume that tasks differ in terms of demands they make on this processing capac