Regressive spectral assimilation bias in speech perception.

Area of Science:

• Psycholinguistics
• Auditory Perception
• Speech Processing

Background:

• Speech perception involves parsing acoustic input into language sounds.
• Existing models focus on acoustic differences between sounds, predicting contrast effects.
• Cases where listeners perceive sounds as similar are under-studied.

Purpose of the Study:

• Investigate under-studied instances of speech sound similarity perception.
• Examine how listeners resolve ambiguity in successive speech sounds.
• Determine if auditory system structure influences speech sound perception.

Main Methods:

• Conducted experiments presenting listeners with ambiguous successive speech sounds.
• Analyzed listener judgments of sound identity and similarity.
• Compared experimental findings with prominent speech perception models.

Main Results:

• Listeners consistently perceived the first sound as spectrally similar to the second when ambiguous.
• This perceived similarity suggested listeners used sound transitions as evidence for the first sound's identity.
• Listeners defaulted to this interpretation when the acoustic signal lacked sufficient information.

Conclusions:

• The findings challenge prominent speech perception models that predict contrast effects.
• Perceptual similarity effects appear to be a default strategy in ambiguous auditory situations.
• These effects likely stem from the general structure of the human auditory system, not just speech-specific mechanisms.