Frequency-specific contributions to auditory perceptual priors: Testing the predictive-coding hypothesis.

Area of Science:

• Auditory Neuroscience
• Perceptual Psychology

Background:

• Perceptual priors, stemming from recent stimuli, influence current perceptions at both high- and low-level processing stages.
• The interaction between high-level expectations and low-level feature processing in forming these priors remains unclear.

Purpose of the Study:

• To investigate whether perceptual priors operate top-down, biasing low-level features based on recent high-level percepts (predictive-coding hypothesis).
• To determine if low-level biases are bottom-up driven by local memory circuits, independent of high-level interpretation.

Main Methods:

• Utilized the "missing fundamental illusion" in auditory perception to decouple low-level acoustic components from high-level pitch perception.
• Analyzed pitch contraction across different timbre categories when the fundamental frequency was absent.

Main Results:

• Contrary to the predictive-coding hypothesis, pitch contraction was not observed towards the previously perceived high-level pitch when the fundamental frequency was missing.
• Pitch contraction occurred towards the physically present frequency, indicating a bottom-up influence.

Conclusions:

• Low-level memory components contribute bottom-up to perceptual priors in auditory perception, operating independently of recent high-level percepts.
• This bottom-up mechanism may stabilize perceptual organization and ensure continuity for similar low-level features across different auditory categories.