Research Paper: The Effect of Knowledge of Result Feedback Timing on Speech Motor Learning in Healthy Adults

Objectives: The current study mainly aimed at studying the effect of Knowledge of Result (KR) feedback timing and result-estimation opportunity before receiving delayed KR on learning a new speech motor skill in monolingual healthy adults. Methods: Thirty-nine Persian healthy adults were randomly divided into three groups. Each group received immediate KR, delayed KR (after eight seconds), or delayed KR (after eight seconds) with self-estimation of the result in the delay interval. All three groups received verbal KR feedback. Participants were trained to produce a French phoneme (/ɪn/) in the context of words in four training sessions. The correct production of the target phoneme was judged by a bilingual Persian-French examiner holding an academic degree in French language teaching. Later, a transfer test and two retention tests were administered. The two retention tests were administered one day and two weeks after the last training session respectively. Results: The effect of feedback timing on motor performance and motor learning was examined by repeated-measures ANOVA. Performance in both acquisition and retention phases was significantly different between groups (P=0.04 for both phases). One-way ANOVA was used to investigate the transfer of learning (P=0.001). Tukey test results indicated that the groups 1 and 2 were different in both acquisition and retention phases and all three groups were different in transfer test. Discussion: The results showed that the immediate KR is beneficial for the acquisition phase, and delayed KR is more beneficial for the retention and transfer tests compared with immediate KR.