In three separate experiments, Ss were provided with auditory, visual, or simultaneous auditory and visual information in a classification task. Difficulty of classification was manipulated by varying the stimulus exposure duration. Consistent bisensory facilitation effects were noted for later trials, with interference evident on earlier trials. Exposure duration influenced rate and not amount of learning, with bisensory performance being most affected by duration. A transfer paradigm was used in Experiment III, and little if any transfer was noted between unisensory and bisensory stimulus conditions. It was concludedthat Ss were extracting the most salient bisensory stimulus components from the auditory and visual modes of information into a unidimensional information configuration.Studies of intersensory processes are, for the most part, designed to determine whether, and/or how, organisms utilize information that is presentd to more than one sensory modality. Typically, a bisensory task is used where stimulus information is provided to the visual and auditory modalities, either simultaneously or separated by some short interval. The design frequently involves three groups, one of which receives combined visual and auditory information, the other two groups experiencing either the auditory or visual stimuli only. An intersensory facilitation effect is noted when the performance of the bisensory group is superior to the performance of each of the other two groups. Intersensory interference refers to circumstances where bisensory performance is inferior to the performance of either of the unisensory groups. While both facilitation and interference have been obtained (as well as the absence of intersensory effects), the most typical result is facilitation, particularly in situations where the stimuli are difficult to detect or discriminate. Excellent reviews of the "intersensory" literature have been provided by Loveless, Brebner, and Hamilton (1970) and Nickerson (1973), with the latter being largely limited to experiments which emphasize a response time (RT) dependent measure.With few exceptions, data on intersensory processes come from experimenal contexts which have used either a detection or discrimination paradigm along with short-duration stimulus exposures. Although there has not been a considerable effort directed toward theoretical development, two different. but not opposing, theories have been proposed. These are the energy summation hypothesis (e.g., Bernstein, 1970) and the preparation-enhancement model (e.g. • Nickerson, 1973). Very briefly, the former attributes bisensory facilitation to the cross-modal summation of stimulus energy, while the latter treats one of the two sources of bisensory information as an accessory which serves primarily to "set." "orient." or prepare the S for the other source of information.At a strictly intuitive level, it would appear that the ability to effectively utilize two sources of simultaneous or near-simultaneous bisensory information would develop as a result of...