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A major component of a dynamical paradigm involves a "scanning" procedure in an attempt to determine an individual's intrinsic coordination tendencies before learning, as well as subsequent changes in the coordination landscape after practice. The purpose of the present study was to evaluate two methods of the scanning procedure. Scans were performed before and after 75 trials of a 90° bimanual-coordination pattern and were compared with early and late acquisition trials. Four groups of participants performed scanning and acquisition trials using a combination of either concurrent visual feedback in the form of Lissajous figures, paced by an auditory metronome, or visual metronomes in the form of flashing stimuli. Analyses revealed that all groups improved performance of the 90° pattern with practice. As predicted by the theory of practice specificity, scanning via the same method as acquisition appears to be valid. Scanning via Lissajous figures when the acquisition procedure was flashing squares was also found to be valid, but not the opposite condition. Reasons for this unidirectional transfer are given with these results suggesting that the sensitivity of a given scanning method might be influenced by the method of acquiring the coordination pattern. [ABSTRACT FROM AUTHOR]

This experiment examined contextual interference in producing a bimanual coordination pattern of 90 degree angle relative phase. Acquisition, retention, and transfer performance were compared in a single-task control group and groups that performed 2 tasks in either a blocked or random presentation. Surprisingly, acquisition data revealed that both the random and control groups outperformed the blocked group. Retention data showed a typical CI effect for performance variability, with the random group outperforming the blocked group. Neither the random nor blocked groups outperformed the control group, suggesting interference of a second task may be as beneficial to learning as extra practice on the initial task. No group effects were found during transfer performance. Results suggest that random practice is beneficial for learning only one task. [ABSTRACT FROM AUTHOR]

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]

Recent experiments (e.g., Danckert & Goodale, 2001; Kahn & Lawrence, 2005) have reported increased end point accuracy for movements that were performed in the lower visual field (LVF) vs. the upper visual field (UVF). To account for these results, it was suggested that there is superior feedback-based processing in the LVF resulting from a motor subsystem advantage in visuomotor processing. Specifically, an overrepresentation of the LVF in the dorsal visual pathway as well as a greater retinal ganglion cell density was implicated. However, it is not clear whether differences in the perceptual subsystem may also play a role in the LVF movement advantage. The goal of the present experiment was to investigate this possibility. Inspection time (IT) is a measurement of the stimulus duration required in order to make a perceptual judgment to some level of accuracy, and thus is thought to measure perceptual processing time (Sadler and Deary, 2001). An accumulator model (Vickers, 1970) suggests that as more time is available to inspect the stimulus, more information is passed into the perceptual system. In the present experiment, participants identified which leg of an asymmetrical "pi" figure was longer. After fixating on a central cross, the stimulus appeared in either the central visual field, the UVF, or the LVF for a brief period (10 conditions between 16.6 ms and 166 ms) before being backward masked. Significant main effects were found in percentage of correct identification for both visual field and duration, as well as a significant interaction between these factors. These results indicate that IT was shortest for central vision. However, differences were also observed between the LVF and UVF, with more correct identifications in the LVF at shorter stimulus durations. This supports the suggestion that more information was available in the LVF, leading to more correct identifications, and may indicate that at least part of the LVF movement advantage may be due to perceptual factors. Supported by NSERC. [ABSTRACT FROM AUTHOR]