Quantitative effects of overlay clutter and information access effort: Examining the scan-clutter trade-off in displays with geospatial maps.

Overlaying images from multiple geospatial databases increases clutter and imposes attentional costs by disrupting focusing attention on each database and dividing attention when comparing databases. Costs of overlay clutter may offset the benefits of reduced scanning between two images displayed separately. In two experiments, we examine these attention issues using computational metrics to quantify clutter. We also examine how the scan-clutter trade-off is modified by different levels of clutter, display separation, and task attentional requirements. Participants viewed information from a geographical terrain database and a schematic map database and made judgments that required focusing attention on either database or integrating information across both. In Experiment 1, databases were presented as either overlaid or adjacent displays, and in Experiment 2, as either overlay, adjacent, or more separated displays. Results showed that response time was modulated by the magnitude of clutter, spatial separation, and task type. Results also revealed that clutter costs dominated those of spatial separation, particularly in tasks requiring focused attention. A computational feature congestion metric of clutter effectively predicted performance but could be improved by incorporating an overlay component, which amplified the costs of clutter. The results provide design guidelines for overlay displays (e.g., head-mounted displays) that will minimize the scan-clutter trade-off. (PsycInfo Database Record (c) 2024 APA, all rights reserved).