Abstract
Purpose: We investigated underling mechanisms of “Contour adaptation Filling-in.” Our questions were: (1)difference between achromaticity and chromaticity, (2)difference between textured and uniform target area, (3)possibility of multiple step filling-in, and (4)resolving conflicting filling-ins by line segments.
Method: “Contour adaptation Filling-in” procedure was that: After 6 second empty fixation, 5s contour adaptation was presented, and then the disappearance of test figure was judged in the next 1s. The test figures were 12 degree diameter annulus or their variants for specified purposes. The background and test figure were near equiluminant, or similar hue or saturation. The adapting contours were the boundaries of annulus with 5Hz flicker. For the question(1), we changed the duration of the target annulus presentation, e.g. 5s meant that during whole 5s adaptation the target was presented together with flicker, 1s meant that the target was presented only for the last 1s of adaptation. For (2), we presented the annulus with textures such as random dos. For (3), the test figure was the concentric annuli with step change brightness or color whose differences were small enough to disappear by the adaptation. For (4), the stimulus equipped with two conflicting filling-ins, e.g. light-gray and dark-gray.
Results: (1)Filling-in of colored target needed a few seconds presentation during adaptation, while the achromatic filing-in did not. (2)Textures in uniform target figure survived filling-in. (3)Whole concentric boundaries were disappeared. Continuous gradation was observed. (4)On the conflicting conditions, the filling-in was not successful. With a separating line segment between conflicting areas subjects observed two uniform areas.
Conclusions: “Contour adaptation filling-in” of uniform, color, and texture features seemed to include different mechanisms. Successful multi-step filling-in suggested that the filling-in functioned locally. The continuous gradation result meant that the filling-in was not simply to neutralize two neighboring areas. The filling-in would be dynamic spatial operation.