Schedule of Events | Symposia

How do harmonic relationships affect grouping of sounds?

Poster Session F - Tuesday, April 1, 2025, 8:00 – 10:00 am EDT, Back Bay Ballroom/Republic Ballroom

Julia M. Leeman¹ (julia.leeman@duke.edu), Cynthia D. King¹, Jennifer M. Groh¹; ¹Duke University

Perceptually, we group sounds from the same source and segregate sounds from different sources. This study characterizes the effects of harmonicity on this process. We used an auditory streaming paradigm in which tones were presented in a repeating fashion: C-AB-C-AB-C-AB etc, with the higher pitch C presented alone and the lower pitches A and B presented simultaneously. Previous work has suggested that the frequency separation between C and B governs whether B groups with A or C (Bregman & Pinker, 1978). Here, we investigated whether the harmonic relationship between A and B affects this grouping by testing two conditions: A and B are an octave apart (consonant), or A and B are a major 7th apart (dissonant). We varied the frequency of C, and participants classified sound patterns as to whether B grouped with A or with C as a function of C’s frequency in the consonant and dissonant conditions. We compared the midpoint and slope of the psychometric curves generated. The consonant and dissonant conditions had a similar midpoint, but the dissonant condition had a sharper slope. Therefore, participants were more sensitive to grouping of tones at a dissonant interval. We suggest the fusion of dissonant intervals may be clearer to participants because the perceptual experience of dissonance requires fusion. This result will help design stimuli to investigate the neural patterns underlying auditory grouping and segregation in nonhuman primates. With these stimuli, we can compare neural responses to sounds that differ in their perception as grouped or segregated.

Topic Area: PERCEPTION & ACTION: Audition