when finger taps are synchronized with an isochronous click, it is known that tap-click asynchrony and its variability increase with the interonset interval (IOI). It remains unclear whether these results are due to the IOI or the intertap interval (ITI) duration. The present study examines how these two factors influence tapping performance by altering the tap-click ratio (i.e., 1: n tapping). It has been shown that holding the ITI constant while decreasing the IOI—so that extra clicks subdivide each tap—results in a reduction of tapping variability, described as a subdivision benefit (Repp, 2003). Two questions remain: Does asynchrony and variability increase with the ITI while holding the IOI constant? Does asynchrony decrease with the IOI while holding ITI constant? Using linear regression, both asynchrony and variability decreased with the IOI, with little additional effect of ITI. In contrast, when using ITI as a predictor, the contribution of IOI was significant, suggesting that IOI is the main determinant of tapping performance. In addition, an ANOVA revealed a disadvantage for 1:3 tapping, supporting a categorical distinction between duple and triple meters since 1: n tapping can engender the subjective feel of different metric structures.

SUBDIVISION BY COUNTING HAS BEEN SHOWN TO improve interval discrimination for durations exceeding 1.2 s (Grondin,Meilleur-Wells, & Lachance, 1999). The present study examined whether simple interval subdivision (bisection) reduces variability of synchronization with a slow metronome. Interval durations ranged from 1 s to 3.25 s.Musically trained participants tapped in synchrony with the metronome while: (1) refraining from any subdivision, (2) mentally bisecting each interval, (3) making additional taps at the bisection points (double tempo tapping), or (4) tapping only at the bisection points (anti-phase tapping). In each task, the standard deviation of asynchronies and intertap intervals was found to increase almost linearly with interval duration, but the slope decreased from condition 1 to condition 4. Differences among conditions were nearly absent with intervals of 1 s (roughly consistent with Grondin et al., 1999), but emerged and increased steadily as interval duration increased. In double tempo tapping, anti-phase taps were less variable than in-phase taps and depended less on the immediately preceding taps. The findings are interpreted in terms of multiple temporal references in synchronization, and their potential relevance to musical ensemble playing is pointed out.