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Nilsu Atilgan, Sheng He; Effects of Stimulus Category and Task Difficulty in the Temporal Window of Crowding. Journal of Vision 2016;16(12):231. doi: 10.1167/16.12.231.
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© 2017 Association for Research in Vision and Ophthalmology.
A peripheral target is more difficult to identify when it is surrounded by flankers. This effect of crowding has been extensively investigated in spatial and temporal domains, with the majority of studies focused on the spatial properties of targets and flankers and their spatial relationships. The current study aims to uncover the effect of task difficulty and stimulus category on the temporal interactions between the target and flankers. Specifically, we examined whether orientation identification of Gabor patches and letters among flankers had different temporal windows. Targets were either Gabor patches (two orientations in easy condition and four orientations in difficult condition) or letters (letter-T in easy condition and letter-G in difficult condition), and they were presented in the right or left peripheral area with the target centered at 8 from fixation surrounded by four flankers. The flankers were presented at 7 different SOAs relative to the target presentation (-150, -100, -50, 0, 50, 100, 150 ms). Results from five subjects show that, consistent with the literature, crowding effect was the strongest when the target and flankers were presented simultaneously (SOA=0), and there was an asymmetry between flankers presented before (SOA 0) and after (SOA 0) the target. When the target was followed by flankers the performance was worse than when the flankers were followed by the target. However, our current data do not show a category nor a task difficulty level dependence, in that the temporal windows of target-flanker interaction are similar for the four types of stimuli used in this study. Our next step is to examine the temporal window of target-flanker interaction using more complex stimuli such as objects or faces.
Meeting abstract presented at VSS 2016
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