Abstract
Our visual system rapidly and broadly extracts distributional information about some feature dimensions, such as size, orientation, and hue (Alverez, 2011; Haberman & Whitney, 2012). We tested whether this information could include distributions of those features over space. When viewing a linear blue-to-yellow gradient, can an ensemble process differentiate that pattern from a yellow-to-blue gradient? Our results suggest not. Observers judged the color direction of a gradient created by a set of numerous colored circles. In the briefly flashed display, observers made systematic eye movements towards one 'end' of the gradient (e.g., the yellow end), suggesting that they needed to sample one section of the gradient to know its direction. As a control condition, in half of the blocks we asked observers to instead estimate the number of dots in the gradient. Despite using identical displays, the eye movements disappeared, with fixation remaining much closer to the gradient's center (t(11) = 5.2, p < 0.001). Judging that yellow is to the right of blue may not be possible via a broad attentional scope. Instead that judgment – or at minimum, storage of the result of that judgment – may require shifting attention to the color of one side (or attentionally localizing the side for a given color).
Meeting abstract presented at VSS 2016