Official websites use .gov
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.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
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connected to the .gov website. Share sensitive
information only on official, secure websites.
Stimuli used in Experiments 1 and 2. (a) Cornsweet circles: nonflickering Cornsweet circles; (b) flickering Cornsweet circles: Cornsweet circles reversing polarity over time; (c) unipolar Gaussians: circles with only a light or a dark edge fading to the color of the background that change between light and dark gray over time; and (d) solid lines: circles with a light and dark gray line at their edge that exchange positions over time.
