Citation

Sewell DK, Lilburn SD, Smith PL. J. Exp. Psychol. Hum. Percept. Perform. 2014; 40(6): 2214-2242.

Copyright

(Copyright © 2014, American Psychological Association)

DOI

10.1037/a0037744

PMID

25222469

Abstract

Research suggests that visual short-term memory (VSTM) has both an item capacity, of around 4 items, and an information capacity. We characterize the information capacity limits of VSTM using a task in which observers discriminated the orientation of a single probed item in displays consisting of 1, 2, 3, or 4 orthogonally oriented Gabor patch stimuli that were presented in noise for 50 ms, 100 ms, 150 ms, or 200 ms. The observed capacity limitations are well described by a sample-size model, which predicts invariance of ∑i(d' i ) 2 for displays of different sizes and linearity of (d' i ) 2 for displays of different durations. Performance was the same for simultaneous and sequentially presented displays, which implicates VSTM as the locus of the observed invariance and rules out explanations that ascribe it to divided attention or stimulus encoding. The invariance of ∑i(d' i ) 2 is predicted by the competitive interaction theory of Smith and Sewell (2013), which attributes it to the normalization of VSTM traces strengths arising from competition among stimuli entering VSTM. (PsycINFO Database Record (c) 2014 APA, all rights reserved).

Language: en