Visual tracking combined with hand-tracking improves time perception of moving stimuli

A number of studies have shown that performing a secondary task while executing a time-judgment task impairs performance on the latter task. However, this turns out not to be the case for certain motor secondary tasks. We show that concomitant secondary motor tasks involving pointing, when performed during a time-judgment task, can actually improve our time-judgment abilities. We compared adult participants' performance in a time-of-movement paradigm with visual pursuit-only and with visual pursuit plus hand pursuit. Rather than interfering with their estimation of stimulus movement duration, the addition of hand pursuit significantly improved their judgment. In addition, we considered the effect of three different movement profiles and four different movement speeds for the moving stimulus. As predicted by Vierordt's law, time judgments of shorter stimuli are overestimated and longer stimuli underestimated. Finally, timing performances appear to improve when the moving target follows a "biological" velocity profile.