Citation

Trick LM, Pylyshyn ZW. J. Exp. Psychol. Hum. Percept. Perform. 1993; 19(2): 331-351.

Affiliation

Department of Psychology, University of Western Ontario, London, Canada.

Copyright

(Copyright © 1993, American Psychological Association)

DOI

unavailable

PMID

8473843

Abstract

Subitizing, the enumeration of 1-4 items, is rapid (40-120 ms/item) and accurate. Counting, the enumeration of 5 items or more, is slow (250-350 ms/item) and error-prone. Why are small numbers of items enumerated differently from large numbers of items? It is suggested that subitizing relies on a preattentive mechanism. Ss could subitize heterogeneously sized multicontour items but not concentric multicontour items, which require attentional processing because preattentive gestalt processes misgroup contours from different items to form units. Similarly, Ss could subitize target items among distractors but only if the targets and distractors differed by a feature, a property derived through preattentive analysis. Thus, subitizing must rely on a mechanism that can handle a few items at once, which operates before attention but after preattentive operations of feature detection and grouping.

Language: en