Weber-Fechner behavior in symmetry perception?
The literature contains several allusions to the idea that detection of (mirror) symmetry in the presence of noise follows the Weber-Fechner law. This law usually applies to first-order structures, such as length, weight, or pitch, and it holds that just-noticeable differences in a signal vary in proportion to the strength of the signal. Symmetry, however, is a higher order structure, and this theoretical note starts from the idea that, in noisy symmetry, the regularity-to-noise ratio defines the strength of the signal to be considered. We argue that the detectability of the symmetry follows a psychophysical law that also holds for Glass patterns. This law deviates from the Weber-Fechner law in that it implies that, in the middle range of noise proportions, the sensitivity to variations in the regularity-to-noise ratio is disproportionally higher than in both outer ranges.
van der Helm
Peter A
PA
Donders Institute for Brain, Cognition, and Behaviour, Radboud University Nijmegen, Nijmegen, The Netherlands. p.vanderhelm@donders.ru.nl
D001288:Attention; D003867:Depth Perception; D004056:Differential Threshold; D004192:Discrimination, Psychological; D006801:Humans; D009949:Orientation; D010364:Pattern Recognition, Visual; D011601:Psychophysics