Symposium (S5): Visual Noise: New Insights

Wednesday 28 August 2013, 09:00-11:00, Hanse

Organizer: D Baker
Over the past three decades, numerous studies have explored the processing of visual stimuli in the presence of added external noise. An important aim of many of these experiments was to estimate the level of internal noise within the observer, and the technique has proved popular in both basic and clinical work across all sensory domains. Recently, however, several studies have begun to question both the fundamental assumptions that underpin this paradigm, and the techniques that experimenters and modellers have commonly used. Specific concerns include the following: 1) Estimates of the distribution of internal noise suggest that it is not normal [Neri, 2013, J Neural Eng] 2) External noise can affect the observer’s processing strategy [Allard & Cavanagh, 2011, Vis Res; 2012, J Vis] 3) Pixel noise masks can suppress the target as well as increasing variance [Baker & Meese, 2012, JoV; Hansen & Hess, 2012, Vis Res] 4) Computational models can make incorrect predictions if they are implemented inappropriately [Klein & Levi, 2009, J Opt Soc Am A] These concerns cast doubt on the interpretation of previous results, and mean that best practise for future research using the external noise paradigm is unclear. The aim of this symposium is to summarise recent work on visual noise, and propose practical and theoretical solutions to the problems outlined above (and others). We will bring together experts in psychophysics and computational modelling of neural systems. The session will consist of six 15 minute talks, followed by a (probably very lively) discussion.
09:00 Introduction
09:10 Adding external noise can trigger a change in processing strategy
R Allard
09:25 Controversies in dealing with visual noise
S Klein, J Ding, D Levi
09:40 Sampling Efficiency and Internal Noise for Summary Statistics
J Solomon, P Bex, S C Dakin
09:55 Consistency of classification images across noise dimension
P Neri
10:10 Reconciling multiplicative physiological noise and additive psychophysical noise
K May, J Solomon
10:25 Convergent evidence demonstrates the suppressive effects of noise masks
D Baker
10:40 Discussion


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