The Effect of Blocked, Random and Mixed Practice Schedules on Speech Motor Learning of Tongue Twisters in Unimpaired Speakers.

There are few investigations comparing practice schedules in speech motor learning, despite certain schedules being recommended for the clinical treatment of speech motor disorders. This study compared effects of random, blocked and mixed practice on tongue twister accuracy in unimpaired speakers. We hypothesized that blocked practice would benefit acquisition of learning, but that random practice and mixed blocked-then-random practice would yield superior retention of learning. We found that the random and blocked-random practice schedules yielded superior accuracy at the end of the acquisition phase of learning and at a 1-week retention test. Exploratory post hoc analyses raised the possibility that the retention effects were most evident when tongue twisters were elicited in a random schedule. Theoretical accounts of these results are discussed.