Auditory-Visual Interactions in Spatial Attention

(Perceptual Development Lab)

Behavioral neuroscience research has shown that the ability to attend to and locate events in space is supported, in part, by overlap and coordination between “maps” of auditory and visual space in the cerebral cortex and in subcortical structures.  Studies of deaf and blind animals and adult humans have shown that when either audition or vision is absent, the ability to attend to and localize events in the periphery of space is heightened.  Further, data shows that the spatial maps that exist in the brain are changed and affected by the absence of one sensory modality.  This suggests that the development of these maps, and their overlap and coordination, is defined in part by sensory input and behavioral experience over time.  We are interested in studying how auditory input affects visual processes, and vice versa, in both real and developmental time. 

Recent studies with hearing and sighted adults have shown that manipulation of the spatial and temporal coincidence of multimodal information has strong effects on behavior.  For example, auditory information can facilitate processing of visual stimuli.  The occurrence of an irrelevant sound facilitates motor responses to a subsequent light appearing nearby, and a flash that is immediately preceded by a sudden sound is detected more quickly and accurately than a flash presented in isolation.  Other interactions between vision and audition can produce illusory effects.  The perception of the location of a sound can be systematically altered after a period of exposure to a consistent spatial disparity between simultaneously presented sounds and lights.  These results show that visual spatial attention does not function in a vacuum but is constantly affected and informed by auditory information. 

While these cross-modal phenomena are an important aspect of our ability to process and localize events in space, little is known about cross-modal functioning across development.  Are young children more or less susceptible to auditory/visual illusions than adults?  When in development do we see the advantages in processing that can result from multisensory information, and is the ability to integrate multisensory information affected by disorders such as autism and learning disabilities?  As we gain a greater understanding of the development of multisensory functions we will apply that understanding to the study of cross-modal plasticity in spatial attention.  We believe these two lines of research will be highly mutually informative.