Contours and borders in animated mimic displays

Previous research has indicated that ambiguities in apparent motion (e.g., direction, rate) can result when color table techniques are used to produce animation in mimic displays. Two experiments were conducted to investigate alternative display designs in which contours (angled vs. straight) and borders (explicit vs. implicit) were varied. In Experiment 1, contours, borders, and temporal frequency interacted. At 5 Hz angled contours improved accuracy significantly. At 10 Hz explicit borders improved accuracy significantly with angled contours but degraded accuracy significantly with straight contours. In Experiment 2, the design of the angled contours was changed to convey less information and an additional border condition was added. Once again, borders and contours interacted: The widest explicit border degraded accuracy with straight contours. Angled contours also improved latency performance. The results suggest that angled contours can reduce ambiguity and improve the effectiveness of animated mimic displays by providing a redundant encoding of rate information. However, this benefit must be weighed against the associated computational costs. A secondary finding was that when contours are straight the borders should be implicit, not explicit. Alternative design solutions for animated mimic displays are also discussed.