Developmental changes in the multisensory temporal binding window persist into adolescence

Abstract

We live in a world rich in sensory information, and consequently the brain is challenged with deciphering which cues from the various sensory modalities belong together. Determinations regarding the relatedness of sensory information appear to be based, at least in part, on the spatial and temporal relationships between the stimuli. Stimuli that are presented in close spatial and temporal correspondence are more likely to be associated with one another and thus 'bound' into a single perceptual entity. While there is a robust literature delineating behavioral changes in perception induced by multisensory stimuli, maturational changes in multisensory processing, particularly in the temporal realm, are poorly understood. The current study examines the developmental progression of multisensory temporal function by analyzing responses on an audiovisual simultaneity judgment task in 6- to 23-year-old participants. The overarching hypothesis for the study was that multisensory temporal function will mature with increasing age, with the developmental trajectory for this change being the primary point of inquiry. Results indeed reveal an age-dependent decrease in the size of the 'multisensory temporal binding window', the temporal interval within which multisensory stimuli are likely to be perceptually bound, with changes occurring over a surprisingly protracted time course that extends into adolescence.

Figure 1

(a) Simultaneity judgment task protocol. Visual representation of the temporal structure between visual (ring flash) and auditory (tone pip) stimuli. The duration of each stimulus was 10 ms and the stimulus onset asynchrony for pairs ranged from 0 to 500 ms. The negative sign represents auditory leading visual presentation and the positive sign denotes auditory lagging conditions. (b) Temporal window derivation in a representative adult subject. Two sigmoids were fitted to discrete data points (open circles), and the overall window size was derived by calculating the sum of the width of each side of the distribution at three-quarters maximum simultaneity report (left ≈ 100 ms; right ≈ 200 ms).

Figure 2

Children and adolescents are less sensitive to audiovisual asynchrony at moderate and long SOAs. Graph shows mean probability of simultaneity report for each group (n = 15 participants/group) at each SOA condition (−500 ms to + 500 ms). Planned comparisons revealed significant differences in probability of simultaneity report between children and adults (* = p < .05) and adolescents and adults (†= p < .05) at moderate and long SOAs. Error bars = ±1 SEM.

Figure 3

Mean window size is smaller in adults than in children and adolescents. Bar graph displays mean window size for children (left), adolescents (middle) and adults (right) (n = 15 participants/group). Children and adolescents have significantly smaller windows than adults, * = p < .05. Error bars indicate ±1 standard error of the mean (SEM).

Figure 4

Multisensory temporal binding windows are smaller in older participants. A significant negative correlation was observed indicating that older participants have smaller windows. An exponential line fit to window size data indicates that age accounts for 20.14% of variance in window size.