Learning and self-stimulation in mute and echolalic autistic children.

The effects of self-stimulation on task acquisition were studied in three mute low-functioning autistic and three echolalic higher-functioning autistic children in multiple-baseline designs. The study found that (a) the echolalic children were able to learn the task without external suppression of their self-stimulation and (b) the mute children were unable to learn the task until their self-stimulation was externally suppressed. It was suggested that the echolalic children may have acquired the ability to discriminate when to self-stimulate, so that their self-stimulation does not interfere with correct responding.