Visual short-term memory compared in rhesus monkeys and humans

L. Caitlin Elmore, Wei Ji Ma, John F. Magnotti, Kenneth J. Leising, Antony D. Passaro, Jeffrey S. Katz, Anthony A. Wright

Research output: Contribution to journalArticlepeer-review


Change detection is a popular task to study visual short-term memory (STM) in humans [1-4]. Much of this work suggests that STM has a fixed capacity of 4 ± 1 items [1-6]. Here we report the first comparison of change-detection memory between humans and a species closely related to humans, the rhesus monkey. Monkeys and humans were tested in nearly identical procedures with overlapping display sizes. Although the monkeys' STM was well fit by a one-item fixed-capacity memory model, other monkey memory tests with four-item lists have shown performance impossible to obtain with a one-item capacity [7]. We suggest that this contradiction can be resolved using a continuous-resource approach more closely tied to the neural basis of memory [8, 9]. In this view, items have a noisy memory representation whose noise level depends on display size as a result of the distributed allocation of a continuous resource. In accord with this theory, we show that performance depends on the perceptual distance between items before and after the change, and d′ depends on display size in an approximately power-law fashion. Our results open the door to combining the power of psychophysics, computation, and physiology to better understand the neural basis of STM.

Original languageEnglish (US)
Pages (from-to)975-979
Number of pages5
JournalCurrent Biology
Issue number11
StatePublished - Jun 7 2011

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Agricultural and Biological Sciences


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