In this experiment, we investigated the role of practice variability (constant versus variable practice) and practice schedule (random versus blocked practice) on spatial and temporal learning of a speech task as a function of aging. The participants were 80 healthy individuals (40–80 years) with no history of cognitive, sensory, or motor disorders. A median split was performed to divide the participants into older and younger groups. The median split was at 59 years of age, thus placing 40 participants in each age group. The participants were assigned to one of four practice groups and practiced a nonmeaningful phrase for two consecutive days. On the third day, the participants reproduced the speech phrase without practice. Data analysis revealed that older participants involved in constant practice demonstrated superior temporal learning of the speech task over participants on variable practice. Older participants on random practice demonstrated better spatial learning of the speech task than did participants on blocked practice. In contrast, there was no effect of practice conditions on spatial and temporal learning outcomes in the younger group. The findings indicate that practice variability and practice schedule influence different aspects of a complex speech-motor learning task among older adults but not among younger adults.
Kaipa is with the Dept. of Communication Sciences and Disorders, Oklahoma State University, Stillwater, OK. Robb and Jones are with the Dept. of Communication Disorders, University of Canterbury, Christchurch, New Zealand.