Multisensory auditory–visual interactions during early sensory processing in humans: a high-density electrical mapping study (2002)
Sophie Molholm , Walter Ritter et al, Cognitive Neurophysiology Laboratory, Nathan Kline Institute for Psychiatric Research, USA; Department of Psychology, The City College of the City University of New York
Scope: This study examined the timing and topography of cortical auditory–visual interactions using high-density event-related potentials (ERPs) during a simple reaction-time (RT) task. Visual and auditory stimuli were presented alone and simultaneously. ERPs elicited by the auditory and visual stimuli when presented alone were summed (‘sum’ ERP) and compared to the ERP elicited when they were presented simultaneously.
Conclusion: Integration of information from multiple senses is fundamental to perception and cognition. The compelling evidence suggests that auditory–visual interactions can affect early visual sensory processing, and the stimuli when presented simultaneously were significantly faster than when they were presented alone. The data also highlight the importance of a detailed consideration of the time course of sensory processing within the individual sensory modalities. The inherent differences in transmission time to cortex of stimulation within the different sensory modalities will likely have considerable effects on the time course and potential neural areas at which multisensory interactions will occur.
Intersensory redundancy facilitates discrimination of tempo in 3-month-old infants (2002)
Lorraine E. Bahrick and Robert Lickliter, Department of Psychology, Florida International University, USA
Scope: further to their study Intersensory Redundancy Guides Attentional Selectivity and Perceptual Learning in Infancy (2000) on intersensory redundancy hypothesis, which holds that in early infancy information presented redundantly and in temporal synchrony across two or more sensory modalities selectively recruits 5-month-old infant’s attention and facilitates perceptual learning more effectively than does the same information presented unimodally, they extend the test to younger infants and to a different amodal property. Three-month-olds’ sensitivity to the amodal property of tempo was investigated.
Conclusion: The newborn infant encounters a world of objects and events that present a richly structured array of stimulation to all the senses. Research demonstrates that young infants are adept perceivers of multimodal stimulation across a variety of natural events. Infants do not perceive disparate sensations through the various sense modalities; rather, they are able to select information that is meaningful and relevant to their actions and to perceive coherent, unitary multimodal events even in the first months of life. Results replicated and extended those in 2000, demonstrating that infants could discriminate a change in tempo following bimodal, but not unimodal, habituation. It appears that when infants are first learning to differentiate an amodal stimulus property, discrimination is facilitated by intersensory redundancy and attenuated under conditions of unimodal stimulation.