Following a review of the literature on responses of autistic persons to environmental stimulation, three experiments are detailed which examine the relationship between modality preference and rate of acquisition of a discrimination task. First, seven autistic children's preference for colored lights and/or simple tones was assessed in a sensory conflict situation (i.e., there was opportunity to respond to either light or tone). In Experiment 2, stimuli were incorporated into a simple serial discrimination task to determine whether stimulus preference was related to the speed at which children learn a discrimination. In the final experiment, the transfer to a school related material was explored. Results are detailed for each S. Among implications reviewed are the importance of developing appropriate assessment techniques for stimulus preferences of lower functioning children and the difficulty of assigning autistic students to homogeneous groups. (CL)