September 2011
Volume 11, Issue 11
Free
Vision Sciences Society Annual Meeting Abstract  |   September 2011
Estimating the growth of discriminative information guiding perceptual decisions
Author Affiliations
  • Casimir Ludwig
    School of Experimental Psychology, University of Bristol, UK
  • Rhys Davies
    School of Experimental Psychology, University of Bristol, UK
Journal of Vision September 2011, Vol.11, 1171. doi:10.1167/11.11.1171
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Casimir Ludwig, Rhys Davies; Estimating the growth of discriminative information guiding perceptual decisions. Journal of Vision 2011;11(11):1171. doi: 10.1167/11.11.1171.

      Download citation file:


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

      ×
  • Supplements
Abstract

Perceptual decision-making is thought to involve a gradual accrual of noisy sensory evidence. Temporal integration of the evidence reduces the relative contribution of dynamic internal noise to the decision variable, thereby boosting its signal-to-noise ratio. We aimed to estimate the discriminative quality of the internal representations guiding perceptual decisions over time, using a novel combination of external noise and signal-to-respond methods. Observers performed orientation discrimination of patterns presented in external noise. We varied the contrast of the patterns and the delay at which observers were forced to signal their decision. Each test stimulus (patterns and noise sample) was presented twice. Analysis of performance at a single contrast level showed that accuracy conformed to a standard ‘speed-accuracy’ curve: discrimination accuracy improved over time according to an exponential growth function. However, observer model analysis of discrimination accuracy and response consistency to two passes of the same stimulus, suggested very little growth in discriminative information. The improvement in performance over time predominantly reflected a decreasing proportion of non-visual, or purely random, decisions. The standard speed-accuracy growth curve collected in signal-to-respond paradigms is therefore not necessarily indicative of an improvement in discriminative quality of the internal representations guiding decision-making. The relative constancy of the discriminative information over time suggests that the dominant source of internal noise limiting performance is static and cannot be compensated for by prolonged evidence integration.

Engineering and Physical Sciences Research Council. 
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×