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Robert Eisinger, Ryan Ly, Hee Yeon Im, Justin Halberda; Ensemble-based Subitizing. Journal of Vision 2012;12(9):1165. doi: 10.1167/12.9.1165.
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© ARVO (1962-2015); The Authors (2016-present)
The enumeration of a small number of objects has been repeatedly shown to consist of two distinct stages dependent on the number of objects. For 1-3 objects, enumeration is fast and accurate. For more than 3 objects, enumeration is slow and less accurate. The former is coined subitizing and the later is counting. These results have led many authors to suggest that each object is selected as a single unit by visual selection or preattentive visual indexing mechanisms (eg. FINSTs) and that subitizing elbows arise because adults are limited to selecting 3 or 4 individual object units at any time. In separate literature, research has been interested in showing ensemble statistics (eg. average size) may empower the visual system to work around the restrictive object based limits. Here, we use subitizing as an assay to test the possibility that an ensemble group of many items must first be selected as a single coherent unit (eg. one group) prior to processing ensemble features for this group. In several experiments, we find that adults show a subitizing elbow when asked to enumerate the number of spatially separated ensembles in a scene. And, just as object based subitizing is disrupted when objects are organized concentrically (Pylyshyn, 1994), ensemble based subitizing is disrupted under these same conditions.
Meeting abstract presented at VSS 2012
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