On the cocktail-party problem: Do children use their exquisite hearing at frequencies above 8 kHz?

The ability to segregate speech streams in challenging listening environments, often referred to as the "cocktail party effect," is critical for children learning effective communication, especially in noisy classroom settings. This developmental process, influenced by factors such as hearing sensitivity, cognitive abilities, and acoustic cues, has not been thoroughly examined in relation to hearing at frequencies above 8 kHz, to which children are exquisitely more sensitive than adults. This represents a critical gap, as emerging studies reveal the significant detrimental effects of filtering out this information. The present study investigated the functional role of extended high-frequency (EHF) sensitivity in speech stream segregation in normal-hearing children aged 4-14 years. Using digit triplets to reduce cognitive load, performance on speech tasks were measured across four segregation cue conditions: baseline (co-located, talker-sex matched), talker-sex cue (talker-sex mismatched), spatial cue (spatially separated target and maskers), and combined (talker-sex cue and spatial cue). Results demonstrate that EHF sensitivity uniquely contributes to improved SRTs in baseline and talker-sex cue conditions, underscoring its importance in situations where talker-specific cues are crucial for stream segregation. However, EHF sensitivity did not influence SRTs in the spatial or combined cue conditions, nor did it significantly affect release from masking in any conditions. These findings suggest that while EHF sensitivity plays a key role in segregating speech streams, its contribution may be less prominent when salient spatial cues are available. This research highlights the importance of EHF sensitivity in children for utilization of talker-specific cues when segregating competing speech in complex listening environments.