Tapping with intentional drift

Abstract

When tapping a desired frequency, subjects tend to drift away from this target frequency. This compromises the estimate of the correlation between inter-tap intervals (ITIs) as predicted by the two-level model of Wing and Kristofferson which consists of an internal timer ('clock') and motor delays. Whereas previous studies on the timing of rhythmic tapping attempted to eliminate drift, we compared the production of three constant frequencies (1.5, 2.0, and 2.5 Hz) to the production of tapping sequences with a linearly decreasing inter-tap interval (ITI) (corresponding to an increase in tapping frequency from 1.5 to 2.5 Hz). For all conditions a synchronization-continuation paradigm was used. Tapping forces and electromyograms of the index-finger flexor and extensor were recorded and ITIs were derived yielding interval variability and model parameters, i.e., clock and motor variances. Electromyographic recordings served to study the influence of tapping frequency on the peripheral part of the tap event. The condition with an increasing frequency was more difficult to perform, as evidenced by an increase in deviation from the intended ITIs. In general, tapping frequency affected force level, inter-tap variability, model parameters, and muscle co-activation. Parameters for the condition with a decreasing ITI were comparable to those found in the constant frequency conditions. That is, although tapping with an intentional drift is different from constant tapping and more difficult to perform, the timing properties of both forms of tapping are remarkably similar and described well by the Wing and Kristofferson model.

Target- and effect-directed actions towards temporal goals: Similar mechanisms?

“…We assumed that spatial variability in target-directed and effect-directed movements is similar (no differences in EP_V). However, because temporal variability usually increases without a pacing signal (Ruspantini & Christolini, 2009; Vardy et al, 2009), we expected to observe higher temporal variability (higher RMT_V) in effect conditions than in target conditions. We further expected that if similar timing mechanisms underlie target-directed and effect-directed actions correlations of RMT_V between effect-directed and target-directed movements for each tempo and both reversal sides should be positive and significant.…”

“…Vardy et al, 2009;Zelaznik, Spencer, & Ivry, 2002). Thus, besides the similarity in shape of trajectory the similarity in timing mechanisms points to similar representations of targets and effects as temporal goals.…”

“…Not only were target-directed and effect-directed movements performed in similar ways, there was also evidence for similar timing mechanisms (positive correlations between effect-directed and target-directed movements in RMT_V, cf. Vardy et al, 2009; Zelaznik, Spencer, & Ivry, 2002). Thus, besides the similarity in shape of trajectory the similarity in timing mechanisms points to similar representations of targets and effects as temporal goals.…”

“…Without the possibility to compare one's own timing to an external event timing errors influence subsequent timing performance. In synchronization–continuation tapping temporal variability increases once the task switches from synchronization (with a metronome) to continuation (without a metronome, Ruspantini & Christolini, 2009; Vardy, Daffertshofer, & Beek, 2009). This phenomenon, known as drift, leads to more variable tapping behavior, which increases as to be produced execution rates decrease, and can be observed even in experienced musicians (Collier & Ogden, 2004).…”

Cadence Modulation in Walking and Running: Pacing Steps or Strides?

“…Not only do indicators of synchronization and the stability of auditory-motor coordination matter when one wants to modulate cadence with auditory pacing, but also the extent to which the prescribed cadence can be internalized when pacing is turned off. This modulating effect of pacing in terms of internalization of the prescribed cadence can be examined using a synchronization-continuation paradigm, with lower deviations from the prescribed cadence after removal of the pacing signal representing stronger internalization [23,[29][30][31]. Furthermore, besides objective findings, the subjective experience of the user about the various pacing types matter for practical reasons such as compliance [32].…”