Listener expectations and gender bias in nonsibilant fricative perception

Area of Science:

• Phonetics and Speech Science
• Auditory Perception
• Linguistics

Background:

• Nonsibilant English fricatives /f/ and /θ/ are acoustically nonrobust, making their perception challenging.
• Previous research indicates formant transitions in adjacent vowels are key cues for distinguishing /f/ and /θ/.
• Vowel and syllable context influence the robustness of the /f/-/θ/ contrast, with /u/ contexts showing greater robustness.

Purpose of the Study:

• To investigate perception biases for English fricatives /f/ and /θ/.
• To determine if gender-based biases in fricative perception exist and their origin.
• To examine the role of vowel acoustics versus frication noise in these perception biases.

Main Methods:

• Production of /f/ and /θ/ stimuli in various syllable structures and vowel contexts by 10 talkers (5 male).
• Perception experiments involving classification of fricatives, including cross-splicing vowel and frication noise portions.
• Presentation of frication noise alone to assess its contribution to perception biases.

Main Results:

• Listeners exhibited a bias to perceive /f/ for female talkers and /θ/ for male talkers.
• This gender-based bias persisted even when vowel and frication noise were cross-spliced, implicating vowel acoustics.
• When only frication noise was presented, a general bias towards /f/ was observed, independent of talker gender.

Conclusions:

• Top-down gender effects significantly influence the perception of nonsibilant fricatives.
• These perception biases originate from the indexical properties of adjacent vowels, not the frication noise itself.
• The acoustic characteristics of vowels, influenced by talker gender, play a crucial role in resolving ambiguous fricative contrasts.