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The purpose of the present experiment was to investigate the time course by which children aged 6-, 8- and 10-year-old adapt and maintain their static balance. Participants (N=30) were required to stand on a force platform with their eyes closed. Ten adult subjects served as a reference group. We analyzed moment-to-moment modifications of quiet stance equilibrium by measuring the range and speed of the center of foot pressure (COP) displacements over time (i.e., periods of 2 s). Results showed that: (1) with age, the range of the COP decreased non-monotonically, with a maximum at 8 years of age, whereas the speed of the COP decreased linearly from 6 to 10 years of age, and (2) over time, both parameters decreased and stabilized, similarly for all age groups, suggesting that the processes underlying the maintenance of an optimal postural stability are mature at least as soon as 6 years of age.

The aim of the present study was to analyze, in children aged 6, 8 and 11, the developmental trend of the attentional cost related to the programming and execution of pointing movements, using a dual-task paradigm. Our results showed that the attentional cost associated to the programming and the first phase of the pointing movement decreased non linearly with age, in particular a plateau between 8 and 11 was observed. This confirmed that the developmental trend of the control of pointing movements is characterized by a no monotonic evolution in which feedforward processes were predominantly used in the younger children, feedback processes were predominantly used in older children (since age 8), and one-line over feedforward processes were used in adults.

The present experiment examined in a visuo-manual task the effects of verbal instructions on the speed/accuracy trade-off across children aged 6, 8 and 10 years and adults. Three different verbal instructions (speed, accuracy and speed-accuracy) had to be respected to perform a pointing task. Analysis of reaction time (RT), movement time (MT) and percentage of targets reach showed that: (1) whatever the age, children were able to comply with the verbal instructions to adapt the velocity and/or the precision of their response (initiation and movement execution); (2) the main age-related difference of the speed-accuracy trade-off concerned the temporal (MT) but not the accuracy (targets reach) characteristics of the pointing movements; and (3) in the older children and even more precisely in adults, a temporal deficit was observed when the accuracy of aiming was required. This deficit increased as accuracy increased. These results were discussed within the theoretical frameworks of the developmental speed processing model proposed by Kail [Psychol. Bull., 109(3) (1991) 490-501] for RT data, and the speed-accuracy trade-off model proposed by Pachella [Pachella, R.G., The interpretation of reaction time in information-processing research, in, Kantowitz, B. (ed) Human Information Processing: Tutorial in Performance and Recognition, Erlbaum, (1974) 41-82] for MT and targets reach data.

The purpose of this experiment was to examine the development of motor preparation across three groups of children aged 6, 8 and 10 years old. The foreperiod duration (500, 1000, 2000 and 4000 ms) and the motor preparation conditions were manipulated using a priming procedure. Two type of primes were provided: (1), a prime carrying no advanced information (neutral condition); and (2), a prime giving advanced information on the nature of the motor response to execute, allowing the participant to prepare for it (selective condition). Reaction time and response errors were analyzed. Results showed that under both conditions, the optimal motor preparation was reached within the same time frame which decreased as age increased. As to the optimal alertness level (neutral preparation), it is maintained longer as age increases, whereas the optimal motor programming level (selective preparation) is reached only for specific foreperiod duration.