Effect of Varying Delays in Auditory Feedback on Key-Tapping of Children

Abstract

A total of 24 children between the ages of 6½ and 11½ yr. tapped on a key in groups of 3 taps, each tap triggering a click 80 db above the threshold of normal hearing. The design of the experiment permitted the click to be heard synchronously with the tap or with a delay which varied from 0 to 1,000 msec., in 100-msec. steps. The effects of delay on the force of taps, the total time for 30 taps, the time during which the finger actually rested on the key, and grouping errors were computed for the synchronous timing and for each of the delay times. Delay had significant disruptive effects on all four parameters. The disruptive effect on total time, time on the key, and grouping errors increased as a function of length of delay, the 1,000-msec. delay being more disruptive than any below 700 msec. The increase in force was significant at all delay times, regardless of the length of delay. Age did not affect sensitivity to delay. The results of our study are surprising in view of the well-established fact that in normal adults speech is most effectively disrupted by a delay time of 160 to 200 msec. The reasons for the difference in findings are as yet conjectural.