CUED Publications database

Variability in encoding precision accounts for visual short-term memory limitations.

van den Berg, R and Shin, H and Chou, WC and George, R and Ma, WJ (2012) Variability in encoding precision accounts for visual short-term memory limitations. Proc Natl Acad Sci U S A, 109. pp. 8780-8785.

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Abstract

It is commonly believed that visual short-term memory (VSTM) consists of a fixed number of "slots" in which items can be stored. An alternative theory in which memory resource is a continuous quantity distributed over all items seems to be refuted by the appearance of guessing in human responses. Here, we introduce a model in which resource is not only continuous but also variable across items and trials, causing random fluctuations in encoding precision. We tested this model against previous models using two VSTM paradigms and two feature dimensions. Our model accurately accounts for all aspects of the data, including apparent guessing, and outperforms slot models in formal model comparison. At the neural level, variability in precision might correspond to variability in neural population gain and doubly stochastic stimulus representation. Our results suggest that VSTM resource is continuous and variable rather than discrete and fixed and might explain why subjective experience of VSTM is not all or none.

Item Type: Article
Uncontrolled Keywords: Adult Algorithms Bayes Theorem Color Perception Humans Memory, Short-Term Models, Neurological Models, Psychological Photic Stimulation Psychomotor Performance Time Factors Visual Perception Young Adult
Subjects: UNSPECIFIED
Divisions: Div F > Computational and Biological Learning
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 11:21
Last Modified: 21 Apr 2014 01:09
DOI: 10.1073/pnas.1117465109

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