P-center judgments are generally insensitive to the instructions given

Area of Science:

• Phonetics
• Speech Perception
• Psychoacoustics

Background:

• The P-center, or perceptual center, of a syllable is crucial for understanding speech rhythm.
• Previous research often used isochrony judgments to study P-centers.
• The reliability of different timing cues for isochrony judgments is not fully understood.

Purpose of the Study:

• To investigate how varying instructions affect syllable timing judgments.
• To determine if listeners can reliably align syllables based on onsets or offsets, rather than P-centers.
• To explore the robustness of P-center alignment as a perceptual timing mechanism.

Main Methods:

• Two experiments were conducted with participants adjusting speech sounds for isochrony.
• Instructions varied, focusing on overall isochrony, syllable onsets, vowel onsets, or syllable offsets.
• Experiment 2 manipulated vowel durations to emphasize differences in syllable rhyme durations.

Main Results:

• Participants found it impossible to align syllables based on offsets under any instruction set.
• Shifting focus to syllable or vowel onsets did not consistently alter timing judgments compared to P-center alignment.
• Results suggest that P-center alignment is the most natural and reliable isochrony judgment for listeners.

Conclusions:

• P-center alignment appears to be the default and most stable perceptual timing strategy for syllables.
• Listeners' ability to reliably judge isochrony is strongly tied to P-center perception.
• Current methods for studying speech timing may be inherently biased towards P-center judgments.