International audienceSeveral prior studies have apparently demonstrated implicit learning of a repeated segment in continuous-tracking tasks. In two conceptual replications of these studies, we failed to reproduce the original findings. However, these findings were reproduced in a third experiment, in which we used the same repeated segment as that used in the Wulf et al. studies. Analyses of the velocity and the acceleration of the target suggests that this repeated segment could be easier to track than the random segments serving as control, accounting for the results of Wulf and collaborators. Overall these experiments suggest that learning a repeated segment in continuous-tracking tasks may be much more difficult than learning from a repeated sequence in conventional serial reaction time tasks. A possible explanation for this difference is outlined

The aim of the experiment was to study the adaptive capacities of children to perform drawing movements while being visually perturbed. Children aged 5-11 years and a group of adults drew diamonds via information provided through a computer screen. The screen display was either upright or rotated 180 degrees. Results showed that the absence of direct vision of the hand yielded more perturbation in the youngest group of children compared to all other groups. In spite of some initial difficulty, all children reached accurate control after five trials. When faced with spatial rotations of the visual field, youngsters were again more perturbed than others. All children showed the same rate of adaptation to visual rotations, but they differed on adaptive strategies. Five- and 7-year-olds shifted to a feedforward mode of control consisting of the production of a rapid gesture, followed by error evaluation in order to correct their next movement. Older children were characterised by a progressive integration of reafferent visual and proprioceptive information. It resulted in an increase in duration of strokes and reduced speed, meaning enhanced on-line retrieval of information. However, 9-year-old children experienced more difficulty recuperating sensory information during movement than 11-year-olds, and kept using error feedback. Finally, visuomanual coordination in children aged 11 years, while slightly differing from that of adults, was not yet totally mature.

Assessing implicit learning in the continuous pursuit-tracking task usually concerns a repeated segment of target displacements masked by two random segments, as referred to as Pew's paradigm. Evidence for segment learning in this paradigm is scanty and contrasts with robust sequence learning in discrete tracking tasks. The present study investigates this issue with two experiments in which participants (N = 56) performed a continuous tracking task. Contrary to Pew's paradigm, participants were presented with a training sequence that was continuously cycled during 14 blocks of practice, but Block 12 in which a transfer sequence was introduced. Results demonstrate sequence learning in several conditions except in the condition that was obviously the most similar to previous studies failing to induce segment learning. Specifically, it is shown here that a target moving too slowly combined with variable time at which target reversal occurs prevents sequence learning. In addition, data from a post-experimental recognition test indicate that sequence learning was associated with explicit perceptual knowledge about the repetitive structure. We propose that learning repetition in a continuous tracking task is conditional on its capacity to (1) allow participants to detect the repeated regularities and (2) restrict feedback-based tracking strategies.

This article focuses on the impact of intentionality on goal directed locomotion in healthy and autistic children. Closely linked with emotions and motivation, it is directly connected with movement planning. Is planning only preserved when the goal of the action appears motivating for healthy and autistic children? Is movement programming similar for autistic and healthy children, and does it vary according to the emotional valence of the object? Moving in a straight line, twenty autistic and healthy children had to retrieve a positive or aversive emotional valence object. The results suggest planning and programming are preserved in an emotionally positive situation. However, in an aversive situation, autistic children appear to have a deficit in terms of planning and sometimes programming.