The effect of motor difficulty on the acquisition of a computer task: a comparison between young and older adults

International audienceThe present study investigated the extent to which the impact of motor difficulty on the acquisition of a computer task varies as a function of age. Fourteen young and 14 older participants performed 352 sequences of 10 serial pointing movements with a wireless pen on a digitiser tablet. A conditional probabilistic structure governed the succession of target keys to be pointed at on a virtual keyboard. Detecting and learning with practice how to use this probabilistic structure was expected to allow the participants to anticipate the location of the targets, and thus to improve pointing performance in terms of speed, accuracy, and trajectory rectitude. Motor difficulty was manipulated through the size of the targets to be pointed at. Results showed that for older participants, but not for younger ones, motor difficulty had a detrimental effect on their ability to learn the probabilistic structure. This finding suggests that decreasing the target size provides complex detrimental influence on the performance, affecting the efficiency of both the motor and cognitive processes involved in the task, especially for the elderly