A PASSIVE PERCEPTUAL LEARNING TASK FOR PRIMAL COLOR MODIFIES DIFFERENCE THRESHOLD OF MIDDLE TONE COLORS
Observers performed a memory task in which they learned the location of a target color in a 4 * 4 colored matrix. Each of the 16 squares within a matrix was assigned one of four unique hues (red, yellow, green and blue), and observers were asked to report the location of a target hue. The initial frame rate was 2 matrices per second and it was increased as observersâ€™ performance improved to as high as 25 matrices per second. Observers performed the color hue discrimination task before and after the memory task. Attending to a particular target color influenced discrimination of middle tone colors which contained the primal color. For example, reddish target color sensitized the hue discrimination of orange-yellow, orange, red, reddish-purple and bluish-purple.