Coordination Dynamics in Redundant and Non-Redundant Motor Tasks

Open Access
James, Eric Guy
Graduate Program:
Doctor of Philosophy
Document Type:
Date of Defense:
June 09, 2009
Committee Members:
  • Karl Maxim Newell, Dissertation Advisor
  • Karl Maxim Newell, Committee Chair
  • John Henry Challis, Committee Member
  • Semyon Slobounov, Committee Member
  • Peter Cm Molenaar, Committee Member
  • coordination dynamics
  • hierarchy
  • posture
This thesis investigated the dynamics of redundant (i.e. with multiple movement solutions) and non-redundant (i.e., in which a movement pattern is the task goal) postural coordination tasks. Previous studies of postural coordination have shown phenomena such as bidirectional phase transitions and transfer of learning that are inconsistent with the established parallel effects in bimanual coordination. The finding of stability in only the in-phase and antiphase patterns in postural coordination may have been confounded by methodological issues, including the analysis of group averaged data. These issues were investigated by testing the hypothesis that there are different hierarchical control structures for redundant and non-redundant coordination tasks and by analyzing individual rather than group-averaged data. In 3 Experiments participants performed a redundant and a non-redundant hip-ankle postural task under a range of experimental conditions. The results showed that transfer between these tasks was negative, transitory and occurred only from the non-redundant task to the redundant. Different timescales of change were found to operate within and between these hierarchical control structures. It was also shown that the prior findings of only in-phase and antiphase coordination patterns in hip-ankle coordination were an artifact of the analysis of group-averaged data. The majority of individuals used more than two coordination patterns in the redundant postural task. The collective pattern of the findings led to the conclusion that: a) there are different hierarchical control structures for redundant and non-redundant coordination tasks; b) these control structures mediate the inconsistent findings previously found in these two types of coordination tasks, and c) different dynamics occur in each type of movement task which leads to the conclusion that the dynamics of the redundant task are different than those captured by the HKB model. It was hypothesized that the relation between the control structures for redundant and non-redundant coordination tasks involves a cooperation and competition between the intrinsic dynamics and properties of the organism, environment and task.