Synchronization of graphic bimanual movements with different semantic load

Abstract

In the current study we analyzed four types of graphomotor tasks that were performed bimanually to examine the synchronization of movements between both hands. The graphomotor tasks were selected based on the hierarchical organization of motor activity proposed by N.A. Bernstein: drawing a repeated broken line (level B), drawing a square from memory (level C2), drawing a house (level D), and writing the word "father (papa)" in capital letters (level E). The study involved 15 right-handed students who completed 64 drawings each, resulting in a total of 960 images analyzed. The mismatch between bimanual movements was analyzed as the difference in the phase curves of both hands. Statistical analysis was performed using the repeated measures ANOVA with factors for the level of movement construction and the hand performing the movement. The semantic complexity of the motor task was found to be directly associated with the magnitude of movement mismatch. Based on the results, we propose two types of bimanual movement synchronization: bimanual dominance (complete and partial) and bimanual competition. Bimanual dominance is specific to semantically simple tasks, whereas bimanual competition is more related to complex tasks.