Parallel and Serial Processing

Abstract

This chapter reviews theoretical and empirical progress that has been made in answering the question “Is processing parallel or serial?” Answers to the question are complicated because the distinction between parallel and serial processing interacts with other basic distinctions, including exhaustive versus self‐terminating search, limited versus unlimited capacity, discrete versus continuous processing, and stochastic versus functional independence. Because of these complications, parallel and serial models readily mimic each other's predictions. Empirical answers to the question are complicated as well because different procedures invoke parallel and serial processing in different ways, and because detailed theories of empirical phenomena often mimic each other's predictions. The chapter reviews progress in distinguishing parallel and serial models of memory search, visual search, dual‐task performance, redundant stimulation, and memory retrieval. It addresses recent alternatives to parallel processing, such as coactivation and mixture models. It ends by evaluating the amount of cumulative progress that has been made in answering the question “Is processing parallel or serial?” and by speculating about prospects for progress in the future.

The serial-parallel dilemma: A case study in a linkage of theory and method

“…Consequently, the issue has been considered in a number of reviews, including two by the first author (Townsend, 1974(Townsend, , 1990a, the latter being intended to be useful for attaining a concise view of the situation at that time. In addition, a trenchant recent review of serial and parallel processing (Logan, 2002) has approached the issues from an alternative and complementary perspective.…”

Serial Consolidation of Orientation Information Into Visual Short-Term Memory

“…Specifically, this limit could result either from a strictly serial process, in which a cognitive bottleneck allows only one item to be consolidated at a time, or from a limited-capacity parallel process, in which two items can be consolidated simultaneously but, because of limits in the bandwidth, each with less precision. Determining whether the rate of consolidation is limited because of a strictly serial process or because of a limited-capacity parallel process has important implications for how one conceptualizes the underlying cognitive architecture and for understanding the fundamental limits that it imposes on visual cognition (Logan, 2002; Townsend & Wenger, 2004). Yet discriminating between these two possibilities has proven to be extremely difficult.…”

Scaling the information processing demands of occupations

“…G. Miller, 1961;Millord & Perry, 1977;Wohwill, 1974). These ideas that stimulus and information overload can have deleterious effects on performance and psychological status have been reaffirmed in the more contemporary literature of cognitive psychology (Logan, 2002;Pashler, 1994). There seems to be little question that multitasking-a condition of stimulus overload-can overtax the resources of the individual both functionally (behavior) and structurally (brain) and can have serious consequences for productivity and behavioral efficiency (Gopher, Armony, & Greenspan, 2000;Meyer & Kieras, 1997;Rogers & Monsell, 1995).…”

“…channel and parallel versus serial information processing (Logan, 2002;Pashler, 1994;Pashler & Wixted, 2002;Wiener & Nagel, 1988). Based on this literature, it is plausible to conclude that environmental stimuli vary from mild to intense and emanate from a variety of sources, and that individuals differ significantly from one another in their capacity to process information from a variety of sources.…”