Please use this identifier to cite or link to this item: http://hdl.handle.net/11667/122
Appears in Collections:University of Stirling Research Data
Title: Speed tuning properties of mirror symmetry detection mechanisms
Creator(s): Sharman, Rebecca
Gheorghiu, Elena
Contact Email: rebecca.sharman@stir.ac.uk
Keywords: Symmetry
Visual Perception
Speed
Motion
Perceptual organisation
Psychophysics
Citation: Sharman, R; Gheorghiu, E (2019): Speed tuning properties of mirror symmetry detection mechanisms. University of Stirling. Dataset. http://hdl.handle.net/11667/122
Dataset Description (Abstract): Motion-direction does not contribute to symmetry perception, but limiting the lifetime of pattern elements improves symmetry detection1. Here we examine whether symmetry mechanisms are tuned to motion speed and if there are speed-selective symmetry channels. Stimuli were dynamic dot patterns containing varying amounts of symmetry. We measured symmetry detection thresholds for stimuli in which symmetric and noise elements moved at the same or different speeds and compared them to those obtained with static and limited-lifetime static patterns. In a second experiment, we measured percentage correct in two conditions: segregated – symmetric and noise elements drifted at different speeds, and non-segregated – symmetric elements drifted at two different speeds, as did the noise elements. We found that (i) performance was worse when symmetric and noise elements had the same speed and improved gradually as the speed difference increased, (ii) thresholds were comparable for all limited-lifetime static conditions, (iii) performance was improved in segregated compared to non-segregated conditions, (iv) modelling suggests that there are speed-selective channels that combine their outputs using probability summation. In conclusion, symmetry mechanisms are tuned to speed, and there are speed-selective symmetry channels, (v) better performance for moving compared to static patterns.
Dataset Description (TOC): SpeedPredictions.xlsx – probability summation predictions VelocitySummary1.xlsx – summary of results Code (folder) – all experimental code Experiment 1 (folder) – raw data from Experiment 1 Experiment 2 (folder) – raw data from Experiment 2
Type: dataset
Contract/Grant Title: Towards a better understanding of mirror-symmetry coding in human vision
Funder(s): Wellcome Trust
Contract/Grant Number: 106969/Z/15/Z
URI: http://hdl.handle.net/11667/122
Rights: Rights covered by the standard CC-BY 4.0 licence: https://creativecommons.org/licenses/by/4.0/
Affiliation(s) of Dataset Creator(s): University of Stirling (Psychology)

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