The development of generalized imitation within topographically determined boundaries.

A multiple baseline technique was employed to examine the experimental development of an imitative repertoire within preselected topographical boundaries. Four severely retarded children, initially nonimitative, were individually trained to imitate a number of motor and vocal responses by shaping and fading procedures. Other untrained responses (probes) were demonstrated to the subjects systematically throughout the ongoing training. Training responses were divided into three topographical types: small motor, large motor, and short vocal responses. Probe responses were divided into four topographical types: small motor, large motor, short vocal, and long vocal responses. Following a multiple baseline format, sequential training of the first three types was begun at different temporal periods of the study; unreinforced imitative generalization was continually measured by the probes. Generalized imitation was observed in each subject (untrained responses were imitated even though unreinforced); but this generalization was restricted to the topographical type of imitation currently receiving training or having previously received training.