AGE-RELATED DIFFERENCES IN TIMING CONTROL OF REPETITIVE MOVEMENT - APPLICATION OF THE WING-KRISTOFFERSON MODEL

Age differences in timing control were investigated in persons between 6 and 75 years. Subjects performed a repetitive finger-tapping task, attempting to match a 550-ms interresponse interval (IRI). Response variability was analyzed using the method of Wing-Kristofferson (1973). An autocovariance technique estimated the proportion of the overall (total) IRI variability contributed by central (clock) and peripheral implementation (motor delay) processes. Significant age and gender differences were revealed only for total and clock variability. Results indicated that (a) young children (6-7 years) had higher variances than all other age groups, (b) older children (9-10 years) were more variable than young and middle-age adults, (c) variances did not differ significantly across three adult age groups (21-75 years), and (d) males were less variable than females for all age groups. In agreement with recent investigations that have used the Wing-Kristofferson methodology, this study suggests that age-related differences in timing control are largely a function of central processes.