Contextual F0 cues can outweigh talker F0 cues in fricative perception

Abstract

Listeners use information in the speech signal as well as linguistic and real-world knowledge to tackle the immense variability of speech. Here, we focus on the use of contextual and talker-bound fundamental frequency (F0) cues during the perception of voiceless fricatives’ center of gravity (CoG). In Experiment 1, Dutch participants heard the sentence Nu komt het woord ?ok (“Now comes the word ?ok”) where “?” denotes a fricative from a synthetic /s-ʃ/ continuum in three carrier F0 conditions (low, mid, high), and indicated whether they heard the high-CoG /sɔk/ “sock” or the low-CoG /ʃɔk/ “(to) trudge.” We found a contrastive effect of context F0 on CoG perception whereby hearing a high F0 carrier sentence led to a lower fricative CoG perception. In Experiments 2a and b, an exposure phase was added where participants either heard a low or a high F0-shifted talker. At test, all participants heard fixed-F0 words /?ɔk/ and indicated whether they heard sok or sjok. Talker F0 guided participants’ responses in both experiments, but across more trials in Experiment 2b than in Experiment 2a. In Experiment 3, combining context and talker manipulations, two groups of participants heard either a low or a high F0 talker in exposure, and both low and high F0-shifted carrier sentences at test. There was a large context F0 effect, but crucially, no talker F0 effect. Overall, we found evidence that both contextual and talker-bound F0 cues have contrastive effects on fricative perception, and that contextual cues, when present and sufficiently reliable, can outweigh talker cues.