Parameterizing spectral contrast effects in vowel categorization using noise contexts.

Area of Science:

• Auditory perception
• Psychoacoustics
• Speech processing

Background:

• Spectral contrast effects (SCEs) demonstrate that context sounds alter target sound perception.
• Previous research faced challenges isolating context spectral properties due to high spectrotemporal variability.

Purpose of the Study:

• Investigate how spectral properties of noise contexts influence SCEs.
• Determine the impact of spectral peak timing and duration on auditory perception.

Main Methods:

• Utilized speech-shaped noise contexts with amplified low-F1 or high-F1 frequencies.
• Manipulated spectral peak presence across onset, offset, and single-epoch paradigms.
• Assessed target sound perception (/ɛ/ vs. /ɪ/) influenced by context spectral peaks.

Main Results:

• SCE magnitudes increased with longer and later spectral peak durations in the context.
• Brief, early spectral peaks in noise contexts still significantly biased target categorization.
• Findings challenge predictions regarding the necessity of prolonged or late spectral context.

Conclusions:

• The timing and duration of spectral information in noise contexts critically modulate auditory perception via SCEs.
• Early spectral information, even when brief, can exert a substantial influence on subsequent sound categorization.
• Results provide new insights into the mechanisms underlying SCEs and auditory adaptation.