The role of attention in binding shape to color

Pictures of easily-identifiable objects with novel colors (e.g. a blue frog) or of forms with arbitrary colors (e.g. a green triangle) were presented briefly at 10.6° eccentricity. Stimuli had strong outlines and vivid fill colors (red, green, yellow, blue, or purple). The same pictures were repeated once in each block of 30 trials for 6, 9, or 12 blocks, and recognition was probed after each block. Shapes were acquired quickly, within 3–4 blocks, whether attention was focused on the pictures or split to a demanding foveal task. Color-shape acquisition was also fast with focused attention, but stabilized at a low level with split attention. Delaying the foveal task restored color-shape acquisition. We suggest that attention facilitates the creation and maintenance of novel color-shape bindings in the visual periphery; without attention, binding is less effective.