Age-specific problems in rhythmic timing

The authors investigated performance in 2 rhythm tasks in young (M = 23.8 y ears) and older (M = 71.4 years) amateur pianists to test whether slowing o f a central clock can explain age-related changes in timing variability. Su ccessive keystrokes in the rhythm tasks were separated by either identical (isochronous) time intervals or varying (anisochronous) intervals. Variabil ity was comparable for young and older adults in the isochronous task; pron ounced age effects were found for the anisochronous rhythm. Analyses of cov ariances between intervals rule out slowing of a central clock as an explan ation of the findings, which instead support the distinction between target specification, timekeeper execution, and motor implementation proposed by the rhythm program hypothesis (D. Vorberg & A. M. Wing, 1996). Age stabilit y was found at the level of motor implementation, but there were a.-c-relat ed deficits for processes related to target-duration specification.