Abstract
Simultaneity is one of the basic rules of multisensory integration and the basis for learning associations between visual and auditory (or tactile) stimuli. Here, we compared the audiovisual and visuotactile simultaneity windows in normal development and in patients who had been deprived of patterned vision during the first 0.3-28.3 months of life (M=4.59 months) by reversible dense cataracts in one or both eyes (n= 13/grp for audiovisual and 12/grp for visuotactile). Participants made judgments about the simultaneity of a flash and a beep (or a tap) that were presented with various stimulus onset asynchronies (SOAs). During normal development, the simultaneity windows became progressively narrower for both visual-leading and auditory-leading (or tactile-leading) SOAs, maturing 2 years earlier for audiovisual (at age 9) than for visuotactile (at age 11) simultaneity. Patients showed reduced and poorly calibrated interactions between vision and hearing. For unilateral patients, the simultaneity window was wider than normal at both visual- and auditory-leading SOAs (ps< .05), a pattern similar to that of younger typically-developing children. For bilateral patients, the simultaneity window was again wider than normal (p< .05) but mainly for the visual-leading SOAs, an asymmetry not seen in normal development. The window of visuotactile simultaneity, in contrast, was entirely normal after both unilateral and bilateral deprivation (ps>.27). Thus, abnormal visual experience, lasting only a few months after birth, has permanent long-term consequences for audiovisual interactions but not visuotactile interactions. The greater variability (thus poorer reliability) in auditory arrival times compared to tactile arrival times may explain the difference. Alternatively, the direct feedback about the source of the tactile stimulus in the visuotactile system, unlike the case of auditory localization in the audiovisual system, may allow the system to be calibrated even after early visual deprivation.
Meeting abstract presented at VSS 2016