Glass patterns are randomized dot arrays that generate the perception of a global structure. They consist of correlated dot pairs which are generated by geometric transformations. The present study employed behavioral and event-related brain potential (ERP) measures to characterize the underlying neuronal processing when such patterns are perceived. Stimuli were circular, parallel, and randomized Glass patterns presented in two isoluminant colors using a choice reaction paradigm. Sixteen subjects were instructed to differentiate between colors with a button-press response. The N170 component increased in amplitude for circular patterns, and this effect was most pronounced bilaterally over occipito-temporal areas. The results suggest that the global percept of form generated by Glass patterns occurs at a stage of visual processing past area V1. © 2005 Elsevier Ltd. All rights reserved.
Ohla, K., Busch, N. A., Dahlem, M. A., & Herrmann, C. S. (2005). Circles are different: The perception of Glass patterns modulates early event-related potentials. Vision Research, 45(20), 2668–2676. https://doi.org/10.1016/j.visres.2005.03.015