Motion prediction and velocity effect 1 Running head: MOTION PREDICTION AND VELOCITY EFFECT

Motion prediction and velocity effect 2 In coincidence-timing studies, children have been shown to respond too early to slower stimuli and too late to faster stimuli. To examine this velocity effect, children aged 6, 7.5, 9, 10.5, and adults were tested with two different velocities in a prediction-motion task which consisted of judging, after the occlusion of the final part of its path, the moment of arrival of a moving stimulus towards a specified position. A similar velocity effect, resulting in later responses for the faster velocities than for the slower, was found primarily in the three younger groups of children (for the longer occlusion conditions: 600 to 1320 ms). However, this effect was not seen in all children in these groups. Individual analyses showed that this velocity effect, when present, is linked to the use of distance rather than time information, or to the confusion between these in extrapolating the occluded trajectories. The tendency to use one type of information or the other is a good predictor of accuracy and variability in this task and a good indicator of the development stage of the participants. Across development, children tend to initially use distance information with poor accuracy but relative consistenc