May 2008
Volume 8, Issue 6
Vision Sciences Society Annual Meeting Abstract  |   May 2008
A visual sense of number
Author Affiliations
  • David Burr
    Dipartimento di Psicologia, Università Degli Studi di Firenze, Via S. Nicolò 89, Florence, Italy, and Department of Psychology, University of Western Australia, Perth WA, Australia.
  • John Ross
    Department of Psychology, University of Western Australia, Perth WA, Australia
Journal of Vision May 2008, Vol.8, 691. doi:
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      David Burr, John Ross; A visual sense of number. Journal of Vision 2008;8(6):691.

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      © ARVO (1962-2015); The Authors (2016-present)

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Evidence exists for a non-verbal capacity to apprehend number, in humans (including infants), and in other primates. We investigated numerosity perception in adult humans, using the psychophysical techniques of adaptation. Adapting to large numbers of dots increased apparent numerosity (by a factor of 2–3), and adapting to small numbers increased it. The magnitude of adaptation depended primarily on the numerosity of the adapter, not on size, orientation or contrast of test or adapter, and occurred with very low adapter contrasts. Varying pixel density had no effect on adaptation, showing that it depended solely on numerosity, not related visual properties like texture density. We propose that just as we have a direct visual sense of the reddishness of half a dozen ripe cherries so we do of their sixishness. In other words there are distinct qualia for numerosity, as there are for colour, brightness and contrast, not reducible to spatial frequency or density of texture.

Burr, D. Ross, J. (2008). A visual sense of number [Abstract]. Journal of Vision, 8(6):691, 691a,, doi:10.1167/8.6.691. [CrossRef]
 Supported by AUstralian ARC

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