Effect of Spatial Release from Masking on Listening Effort in Different Semantic Contexts
Humans often communicate and learn in noisy, complex listening environments. Here, we investigated the effects of spatial hearing and semantic context cues on speech intelligibility and listening effort in young adults with typical hearing. The listening task included conditions in which target speech and speech maskers were either spatially co-located or separated. Target sentences were either semantically coherent or anomalous, while the masker comprised a mixture of two coherent sentences. Results showed higher speech intelligibility in spatially separated than co-located conditions, demonstrating a robust spatial release from masking (SRM), which is consistent with prior findings. SRM did not differ between semantically coherent and anomalous sentences, indicating comparable benefits of spatial cues across semantic contexts. However, within each spatial configuration, intelligibility was higher for coherent than anomalous sentences. Listening effort, indexed by peak pupil dilation in pupillometry measurement, was reduced in spatially separated conditions, suggesting a trend toward a release from listening effort. Analysis of the timing of peak pupil dilation revealed a significantly delayed peak dilation for anomalous sentences in the co-located condition compared with coherent sentences in the separated condition, indicating increased processing demands in the absence of spatial and semantic cues. Finally, SRM was correlated with the magnitude of release from listening effort for coherent sentences, but not for anomalous sentences, suggesting that intelligibility and listening effort benefits might co-occur when contextual cues are available.