Two mechanisms underlying auditory dominance: Overshadowing and response competition.

There are occasions when infants and children have difficulty in processing arbitrary auditory-visual pairings, with auditory input sometimes attenuating visual processing (i.e., auditory dominance). The current research examined possible mechanisms underlying these auditory dominance effects in infants and 4-year-olds. Do auditory dominance effects stem from auditory input attenuating encoding of visual input, from the difficulty of inhibiting auditory-based responses, or from a combination of these factors? In five reported experiments, 4-year-olds (Experiments 1A, 1B, 2A, and 2B) and 14- and 22-month-olds (Experiment 3) were presented with a variety of tasks that required simultaneous processing of auditory and visual input, and then we assessed memory for the visual items at test. Auditory dominance in young children resulted from response competition that children could not resolve. Infants' results were not as robust, but they provided some evidence that nonlinguistic sounds and possibly spoken words may attenuate encoding of visual input. The current findings shed light on mechanisms underlying cross-modal processing and auditory dominance and have implications for many tasks that hinge on the processing of arbitrary auditory-visual pairings.