Effects of blocked versus random practice by mentally retarded subjects on learning a novel skill.

The purpose of this study was to assess the effects of different practice conditions on mentally retarded subjects learning a novel task. 20 subjects with a mean IQ of 51.82 were randomly assigned to one of two practice conditions. The first group practiced at three different speeds (60, 30, and 15 rpm) on the pursuit rotor using a block arrangement in which each speed was practiced for five consecutive trials of 20 sec. duration before practicing at the next speed. The second group used random practice performing 15 trials of the pursuit rotor so three speeds were randomly distributed over the 15 trials. Both groups on the next day performed 15 trials of 20 sec. duration on the pursuit rotor at the transfer speed of 45 rpm. Analysis showed no significant differences among practice conditions which provided 10 min. of experience prior to test.