Abstract
Closure is an emergent perceptual feature that the visual system might extract as a primitive feature of an object. The discrimination of closure is typically faster and easier than that of other geometrical features (Donnelly et al., 1991; Pomerantz et al., 1977; Treisman and Paterson, 1984). The specific nature of closure may be important for the computing object representations. However, there are some questions still unclear: When do closed figures begin deviating from open figures? What is the neural substrate of this perceptual advantage? To investigate these questions, we recorded event-related potentials (ERPs) during a passive observation paradigm. In our study, six pairs of stimuli were used to assess the difference between closed and open figures. Only one of the two figures in each pair was closed, while other low-level features were carefully controlled. We found closed figures deviated from open figures around 110 ms (t(13) = 2.16, P<0.05), with smaller N1 amplitudes for closed than open figures (-5.3uv vs -8.6uv) at almost identical latency (121.8ms vs. 122.7ms). From these results we propose, compared to open figures, the closed figures need less perception processing at early stages of the visual system. To test this hypothesis, we employed a continuous flash suppression (CFS) paradigm to compare the perception of closed and open figures. Same figures were used in CFS experiment. We find closed figures took less time to be perceived after the suppression (1677ms vs. 1951 ms) at a slightly better accuracy (99.1% vs. 97.9% correct). Our results indicate that, closed figures were discriminated from open figures at around 110 ms. compared to open figures, the closed figures possessed a perceptional advantage and were more rapid to reach awareness during CFS. This was reflected in the ERP traces: closed figures induced smaller N1 amplitudes than open figures.
Meeting abstract presented at VSS 2012