This study was concerned with the possibility of modifying the influence of stimuli on other simultaneous sensory processes by training of the CR type. The following conditions were used with different groups of subjects in the CR training procedure: (1) S merely paid attention to light and sound as they were presented together; (2) in addition to paying attention, S repeated the words "light" and "sound" while the stimuli were present; (3) in addition to paying attention, S gripped a hand dynamometer; and (4) in addition to paying attention S received a shock while the stimuli were present. Before the CR training procedure, a stimulus affecting one of the two senses had the effect of increasing the intensity of the other simultaneous sensory response; but after the CR training, a stimulus affecting one of the two senses decreased the intensity of the other simultaneous response. The inhibiting influence of one sensory process on the other simultaneous sensory response was greatest after S had performed an overt motor act in the CR training procedure. Only a slight modification could be produced in the sensory-verbal-judgment process. It is concluded that learning cannot be thought of as being dependent upon organic processes located exclusively in the central nervous system. (PsycINFO Database Record (c) 2006 APA, all rights reserved)