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Melanie Palomares, Mark Pettet, Vladimir Vildavski, Chuan Hou, Anthony Norcia; Visual evoked potentials for dynamic Glass pattern perception in 4– month old infants. Journal of Vision 2008;8(6):690. doi: 10.1167/8.6.690.
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© ARVO (1962-2015); The Authors (2016-present)
Glass patterns are moirés created from a sparse random dot field paired with its rotated, expanded or translated copy. Because discrimination of these patterns is not based on local features, they have been used extensively to study global integration processes. Here, we investigated whether 4–5 month old infants (n=16) are sensitive to the global structure of “dynamic” Glass patterns by measuring Visual Evoked Potentials across the occipital pole. Dynamic Glass patterns are static Glass patterns that are sequentially-presented, and induce a strong illusion of motion. We presented circular Glass patterns that were globally updated at 1.0 Hz (That is, the organized pattern was presented for 500 ms then followed by random pattern for 500 ms). The dot pairs were 6.4 × 6.4 min white squares with a 25.6 min separation presented on a black background, and were locally updated at 20 Hz. Although we found strong sensitivity to the appearance of the local dots, we found no evidence for sensitivity to the global structure of the dynamic Glass patterns in the infants. When we connected the dot pairs of the Glass pattern with lines, we observed a significant difference between organized- versus randomized-field responses. We also recorded strong differential responses to organized versus randomized arrays of Gabor patches. Together our results suggest that the insensitivity to structure in conventional Glass patterns is at least partially due to inefficiencies in extracting the local orientation cues generated by the dot pairs. Once the local orientations are made unambiguous, infants can integrate these signals over the image.
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