Effects of Color Commonality of Overlay Clutter and Information Access Effort on Tasks Requiring Visual Search

The amount and color of overlay clutter can impede focusing attention on one layer of information from multiple sources, and influence dividing attention when comparing across layers. The current experiment examined the effect of information access effort and color commonality of overlay clutter on performance. Participants viewed maps with two domains of information that were either overlaid, adjacent, or separated, and answered questions about either both domains (integration) or one domain (focused attention). The overlaid information was either similar (green) or dissimilar (red) in color relative to the background. Overlaid displays benefited integration tasks but imposed a cost to focused attention tasks for accuracy but not response time. Increased display separation did not impose performance costs. Computational models account for some costs of clutter in overlay displays but the color similarity between databases also contributes to cost and benefits of overlay in a fashion not currently considered by such models.