Abstract

Using a curve-tracing task that requires subjects to determine whether two Xs lie on the same curve or not, we carried out two experiments to test whether visual curve-tracing is qualitatively different from mental curve-tracing. We presented curves and an X before another target X was presented, and required subjects to determine if the X in the target display lies on the curve that contained the other X in the preview display. In experiment 1, the ISI between the preview display and the target display was 1 sec, whereas the ISI in experiment 2 was varied from 100ms to 2 sec. Since it was assumed that at the ISI level of 1 or 2 sec subjects must perform curve tracing operation based on mental imagery, it can be called 'mental curve-tracing', whereas the curve-tracing in the previous studies and the one using 100ms ISI level in experiment 2 can be called 'visual curve-tracing', As results, the response time for determining whether two Xs lie on the same curve increased with X-X distance regardless of ISI, suggesting that a serial curve-tracing processing was needed in both mental and visual curve-tracing tasks. It is also suggested that both the visual curve-tracing and the mental curve-tracing may share the same elemental operations and routines.