Wilken, Patrick and Ma, Wei Ji (2004) A detection theory account of change detection. Journal of Vision, 4 (12). pp. 1120-1135. ISSN 1534-7362 http://resolver.caltech.edu/CaltechAUTHORS:WILjov04
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Previous studies have suggested that visual short-term memory (VSTM) has a storage limit of approximately four items. However, the type of high-threshold (HT) model used to derive this estimate is based on a number of assumptions that have been criticized in other experimental paradigms (e.g., visual search). Here we report findings from nine experiments in which VSTM for color, spatial frequency, and orientation was modeled using a signal detection theory (SDT) approach. In Experiments 1-6, two arrays composed of multiple stimulus elements were presented for 100 ms with a 1500 ms ISI. Observers were asked to report in a yes/no fashion whether there was any difference between the first and second arrays, and to rate their confidence in their response on a 1-4 scale. In Experiments 1-3, only one stimulus element difference could occur (T = 1) while set size was varied. In Experiments 4-6, set size was fixed while the number of stimuli that might change was varied (T = 1, 2, 3, and 4). Three general models were tested against the receiver operating characteristics generated by the six experiments. In addition to the HT model, two SDT models were tried: one assuming summation of signals prior to a decision, the other using a max rule. In Experiments 7-9, observers were asked to directly report the relevant feature attribute of a stimulus presented 1500 ms previously, from an array of varying set size. Overall, the results suggest that observers encode stimuli independently and in parallel, and that performance is limited by internal noise, which is a function of set size.
|Additional Information:||Copyright © 2004 by The Association for Research in Vision and Ophthalmology. Received June 28, 2004; published December 29, 2004. This research was supported by the Rosamund Alcott Fellowship, California Institute of Technology (PW), the Netherlands Organisation for Scientific Research and the Swartz Foundation (WJM), and National Institute of Mental Health and National Science Foundation grants to Christof Koch. We would like to thank Tamara Becher for running the initial version of Experiments 1-3 as a summer undergraduate research fellow (SURF). We also thank William Banks, Jochen Braun, Jon Driver, Miguel Eckstein, Farshad Moradi, John Palmer, William Prinzmetal, Ron Rensink, Dan Simons, and Preeti Verghese for helpful discussions and useful suggestions. Finally, we would like to thank Christof Koch for both the intellectual and practical support he offered us during our time as postdoctoral scholars within his laboratory. Commercial relationships: none.|
|Subject Keywords:||feature judgment, visual short-term memory (VSTM), signal detection theory, change blindness, high-threshold theory, capacity limitations|
|Official Citation:||Wilken, P., & Ma, W. J. (2004). A detection theory account of change detection. Journal of Vision, 4(12):11, 1120-1135, http://journalofvision.org/4/12/11/, doi:10.1167/4.12.11.|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Archive Administrator|
|Deposited On:||20 Mar 2007|
|Last Modified:||26 Dec 2012 09:33|
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