Orthogonal oscillators in the bimanual coupling of different spatial forms
Abstract
When continuous circles and reciprocal lines are combined in a bimanual task, the circles become less circular and more elliptical and the lines become less linear and more elliptical (Franz, Zelaznik, & McCabe, 1991). The present study was an attempt to examine what features of the spatial-temporal patterns of the tasks contribute to these spatial accommodation effects. Moreover, the present study examined whether the spatial and temporal accommodation observed could be described in terms of component oscillatory processes. In Experiment 1, nine groups of subjects (6 per group) performed bimanual tasks that involved reciprocal lines (X or Y dimension) performed by each limb, reciprocal lines performed by one limb and continuous circles performed by the other limb, or continuous circles performed by each limb. These movements were to be performed at a specific amplitude/diameter, at a preferred pace. Amplitude, phase, and frequency characteristics of the X and Y dimensions of the motions of pens used to draw the tasks were analyzed. Accommodation in amplitude was observed in the major dimensions of all bimanual tasks. Long amplitude movements became shorter and short amplitude movements became longer when two movements of different required amplitudes were paired, and these amplitude changes were linear with respect to the difference in the required amplitudes of the tasks. Displacement in the shared dimensions of the left- and right-limb tasks also was highly correlated (i.e., coupled); whereas, the displacement between the X and Y dimensions within a limb and between the limbs was uncorrelated (i.e., uncoupled). Moreover, the frequency ratio of the movements of the two limbs was close to 1:1 or 1:2. These results can be described in terms of oscillatory processes. Experiment 2 examined the joint topologies of two subjects who performed each condition tested in Experiment 1. Analyses of the angular displacement at the elbow and shoulder joints indicated that a wide range of variance occurred at the joint level despite the robust patterns observed at the endpoint trajectories.
Degree
Ph.D.
Advisors
Zelaznik, Purdue University.
Subject Area
Psychology|Experiments|Neurology
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