Maturation of the Precedence Effect: Honoring Bill Hartmann's wisdom

The precedence effect (PE) is a perceptual phenomenon whereby the first-arriving sound is assigned greater perceptual weight than delayed reflections. The PE matures during childhood, when establishment of accurate spatial hearing skills is paramount to a child’s ability to navigate in everyday, reverberant environments. To simplify natural reverberant situations, studies on the PE use lead-lag stimuli with delays that occur naturally in rooms. We investigated spatial hearing in nearly 80 participants aged 5–25 years, using brief trains of noise bursts. On PE conditions, the lead was left or right of midline at varying angles with the lag fixed at midline. Single source stimuli served as control. Results showed significant age effects in accuracy for PE and single conditions; a more protracted maturation on PE conditions indicates that perceptual dominance of the lead (strength of the PE) matures into adolescence. In other studies, we harnessed paradigms that involved sound localization in a multi-loudspeaker space to investigate children’s ability to ignore information from the lag enough to be able to localize the lead. In older children, strong effects of lead-lag delay impact localization. Importantly, the task is critical to engaging young children, and cognitive factors are likely to also play a role. [Work supported by NIH-NIDCD Grants R01DC020355 and R01DC019511 to R.Y. Litovsky.]