Effects of mental age, knowledge of results, and social reinforcement on motor performance.

The effects of mental age (MA), knowledge of results, and social reinforcement on performance on a speed motor task by mildly mentally retarded children was investigated. Significant main effects were found for the variables of MA and social reinforcement and significant interactions for the MA x Social-Reinforcement conditions and the Knowledge of Results x Social-Reinforcement conditions. Post hoc analysis indicated that high-MA subjects performed significantly better under verbal praise conditions than did low-MA subjects. Also, knowledge of results was most effective in the presence of verbal praise. We suggested that verbal praise sensitized subjects to attend to the knowledge of results cue.