Age-related features of memorizing a sequence of movements specified by a visual template

Abstract

Here we report results of the study of memorization and retention of serial visuospatial stimuli at different ages: in children, adolescents and adults. The subjects were asked to reproduce broken lines – sequences of vertical and horizontal line segments. These lines were presented (1) as a static image and (2) as a dynamic object – a cursor moving along a broken line whose trajectory needed be remembered and reproduced. The complexity of the trajectories was set by their length and varied from 4 to 6 elements. The reproduction of the memorized pattern was induced by an audio signal.
We analyzed the total number of errors, as well as the temporal characteristics: reaction time (RT) and average time of the reproduction of a single element in the sequence (MT). Our results showed that the error rate decreased with age, which was typical mostly for the dynamic mode. Teenagers performed the task much more accurately compared to children, yet not as accurate as adults. RT increased markedly by adolescence and remained relatively high in adults. Adolescents and children showed comparable average MT that was higher than adults’.
The increase in accuracy of reproduction with age may reflect an improvement in the accuracy of sequence representation in working memory. The increase in latent time while preparing the motor response may be associated with a more detailed planning of the upcoming serial action. According to our data adolescents take intermediate position between children and adults: their representations of sequences are already of high quality and completeness whereas planning of upcoming serial action is comprehensive. However, they show insufficient motor control, which results in greater role of on-line programming in performing series of movements. The investigation of the role of the mode (static/dynamic) showed that the error rates in the two modes converge with age, whereas the temporal characteristics, on the contrary, become different.