Development of sensitivity to interaural coherence for binaural fusion

Binaural fusion reflects the ability to combine signals from the two ears into a single percept. For normal-hearing adults, increasing interaural coherence or the statistical similarity of the signals at the two ears promotes binaural fusion. How children fuse binaural signals of varying interaural coherence is unexplored. The goal of this study was to investigate the development of the effect of interaural coherence on binaural fusion. Twenty-seven children (i.e., 12 children between 7–11 years old and 15 children between 12–17 years old) and 28 adults with normal hearing completed a binaural fusion task where the interaural coherence of the signal envelope was systematically manipulated between 0.4 and 1.0. Preliminary results showed that all listener groups on average showed changes in binaural fusion as a function of interaural coherence, with more binaurally fused percepts when the signals had high interaural coherence. When compared to adults and the 12- to 17-year-old children, who fused binaural signals at a similar interaural coherence, younger children 7–11 years old fused binaural signals with a lower interaural coherence—suggesting a poorer ability to perceive unfused percepts for signals with reduced interaural coherence. [Work supported by NIH R21DC020532, R01DC018529, and T35DC008757.]