ePoster

Humans can use positive and negative spectrotemporal correlations to detect rising and falling pitch

Parisa Vaziri, Damon Clark, Samuel McDougle
COSYNE 2025(2025)
Montreal, Canada

Conference

COSYNE 2025

Montreal, Canada

Resources

Authors & Affiliations

Parisa Vaziri, Damon Clark, Samuel McDougle

Abstract

To discern speech or appreciate music, the human auditory system detects how pitch increases or decreases over time. However, the algorithms used to detect changes in pitch, or pitch motion, are incompletely understood. Here, using psychophysics, computational modeling, functional neuroimaging, and analysis of recorded speech, we ask if humans can detect pitch motion using computations analogous to those used by the visual system. We adapted visual stimuli to create novel auditory correlated noise stimuli that elicit robust pitch motion percepts. Crucially, these stimuli are inharmonic and possess no persistent features across frequency or time, but do possess positive or negative local spectrotemporal correlations in intensity. Psychophysical experiments revealed that humans judge pitch direction based on positive or negative spectrotemporal intensity correlations. The key behavioral result---people’s robust sensitivity to the negative spectrotemporal correlations---is analogous to illusory “reverse-phi” motion in vision, and thus constitutes a new auditory illusion. Our behavioral results and computational modeling led us to hypothesize that human auditory processing may employ pitch direction opponency. fMRI measurements in auditory cortex supported this hypothesis. To link our psychophysical findings to real-world pitch perception, we analyzed recordings of speech and discovered that pitch direction was robustly signaled by the same positive and negative spectrotemporal correlations used in our psychophysical tests, suggesting that sensitivity to both positive and negative correlations confers ecological benefits. Overall, this work reveals that motion detection algorithms sensitive to local correlations are deployed by the central nervous system across disparate modalities (vision and audition) and dimensions (space and frequency).

Unique ID: cosyne-25/humans-positive-negative-spectrotemporal-ad0f702e