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Masayuki Sato, Keiji Uchikawa; Comparison of effects of the spatial attention on stereo and motion discrimination thresholds. Journal of Vision 2010;10(7):270. doi: 10.1167/10.7.270.
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© ARVO (1962-2015); The Authors (2016-present)
In order to examine whether effects of the spatial attention depend on the dimension of visual functions we compared magnitudes of attentional influences on stereo and motion discrimination thresholds by using the center-periphery dual visual task paradigm. The visual threshold was measured in the following four conditions. In the center-only condition (condition 1) a square target of 1° size was presented on a CRT monitor at 2° eccentricity in 8 possible directions (up, down, right, left and four oblique directions) in the visual field. In the periphery-only condition (condition 2) the target of 5° size (for stereo) or 2° size (for motion) was presented at 10° eccentricity. In the center-priority condition (condition 3) the central and peripheral targets were presented simultaneously while the observer paid more attention to the central target. In the periphery-priority condition (condition 4) more attention was paid to the peripheral target. The conditions 1 and 2 provided the baseline performance. In Experiment 1 we measured stereo thresholds with a staircase method. A random dot stereogram subtending 29° by 29° was presented for 0.2 s while the observer fixated at the central fixation point. Crossed or uncrossed disparity was given to the target and the position of the target was indicated by a white-line square. The observer's task was to indicate the polarity of depth. In Experiment 2 motion thresholds were measured. Luminance modulation and rightward or leftward motion was given to the target. The observer's task was to indicate the direction of motion. The results showed that stereo thresholds elevated almost exclusively for the less attended target. The magnitudes of stereo threshold elevation were in up to 0.5 log unit while the effects of spatial attention for motion threshold were less clear. It appears that stereo discrimination processing needs more spatial attention than motion discrimination processing.
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