Abstract

Gredebäck, G., von Hofsten, C., & Boudreau, J. P. (2002) Infants’ visual tracking of continuous circular motion under conditions of occlusion and non-occlusion. Infant Behaviour and Development, 25, 161-182.



We investigated horizontal and vertical gaze in 9-month-old infants while tracking a fully visible or partly occluded target moving in a circular trajectory. The possibilities for using a corneal-reflection technique (ASL) in such tasks were explored. Data show that horizontal tracking is adult-like at this age over frequencies investigated (0.05–0.4 Hz), vertical tracking is adult-like over the three lowest fre- quencies, whilst performance deteriorated at 0.4 Hz. During occlusion the rate of successful predictions increased with increasing durations of occlusion, from 250 to 5,000 ms. The latency time before making a predictive move towards the other side of the occluder also increased with duration of occlusion. These predictions are not based on a simple application of inertia but based on more complex non-linear extrapolations.