Interlimb versus intralimb anchoring in a novel bimanual coordination pattern.

Anchoring has been defined as synchronizing a point in a movement cycle with an external stimulus, and has shown to affect performance of in-phase and antiphase bimanual movement patterns (Byblow et al., 1994; Fink et al., 2000). The present experiment examined various anchoring strategies during the acquisition and transfer of a novel, complex bimanual coordination movement pattern. Participants performed a 90° pattern anchoring either one reversal point per movement cycle, both reversal points of one arm (i.e., intralimb), or one reversal limb of each arm (i.e., interlimb) to a metronome. Comparison between the single metronome group and double metronome groups provided a measure of the benefit of anchoring, whereas comparison between the two double metronome groups provided a measure of the benefit of intralimb versus interlimb timing information. Analysis of the accuracy of hand positions relative to the metronome pulse and the variability of limb reversal points revealed that the groups differed in their anchoring strategies. Analysis of performance of the 90° pattern showed group differences during initial acquisition (although these differences were minimized by the end of the acquisition period) and transfer performance during a speeded condition. These group differences were attributed to the timing information rather than the varying anchoring strategies, suggesting anchoring may not provide benefit to a nonintrinsic coordination pattern. In addition, contrary to previous research (Fontaine et al., 1997; Zanone & Kelso, 1994), scanning data showed that development of the new pattern resulted in a temporary destabilization of the in-phase pattern and an improvement in the antiphase pattern.This research was supported by the Social Sciences and Humanities Research Council of Canada and Canadian Institute of Health Research. [ABSTRACT FROM AUTHOR]