Results of a study involving 10 mentally retarded and 10 nonretarded (mean age 16 and 4 years, respectively) indicated high levels of acquisition and maintenance for both groups. No difference occurred in magnitude of acquisition, but the mentally retarded Ss took approximately three times as many trials to complete training. (Author/CL)

The study investigated the influence of intertrial interval duration on the performance of three autistic children (ages 2 to 12) during teaching situations. The results showed that the short intertrial intervals always produced higher levels of correct responding than the long intervals. (Author/PHR)