Trick L M, Pylyshyn Z W
Department of Psychology, University of Western Ontario, London, Canada.
J Exp Psychol Hum Percept Perform. 1993 Apr;19(2):331-51. doi: 10.1037//0096-1523.19.2.331.
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.
数感，即对1至4个物品的计数，速度快（每个物品40 - 120毫秒）且准确。计数，即对5个及以上物品的计数，速度慢（每个物品250 - 350毫秒）且容易出错。为什么少量物品与大量物品的计数方式不同呢？有人认为数感依赖于一种前注意机制。受试者能够对数感不同大小的多轮廓物品进行数感判断，但不能对同心多轮廓物品进行数感判断，因为同心多轮廓物品需要注意力处理，因为前注意格式塔过程会将来自不同物品的轮廓错误分组以形成单元。同样，受试者能够在干扰项中识别目标物品，但前提是目标物品和干扰项在特征上存在差异，而特征是通过前注意分析得出的属性。因此，数感必须依赖于一种能够一次性处理少量物品的机制，该机制在注意力之前但在特征检测和分组的前注意操作之后起作用。
