# Individual and population differences in the representation of harmonic sounds

> **NIH NIH F31** · HARVARD MEDICAL SCHOOL · 2021 · $33,790

## Abstract

Project Summary/Abstract
Many of the most important sounds humans hear, including speech and music, are harmonic, and are in part
defined by their fundamental frequency (f0). The perception of f0, often referred to as “pitch”, has historically
been thought to reflect mechanisms that estimate f0 from a sound’s harmonics. But the variety of situations
where pitch is utilized raises the possibility of underlying mechanistic diversity. For example, while the absolute
f0 of a sound can be important, as when recognizing the gender of a speaker, it is often more important to
determine how the f0 has changed over time, as when differentiating a question from a statement. This could be
done by estimating the f0 of two sounds and comparing those two estimates, or alternatively, by recognizing
some other change between two sounds without first estimating the f0s, such as tracking how the harmonics
shift together. In addition to conveying pitch information, harmonic sounds are often important for sound
segregation. Harmonic structure can be used to segregate a single sound from a mixture, for example, picking
an individual speaker out of a group. Harmonic structure may also aid in detecting sources in other kinds of
background noises (such as air vent noise – noise that does not have harmonic structure). The purpose of this
project is to uncover mechanisms used to hear harmonic sounds, both to extract pitch information and to
segregate concurrent sounds, by leveraging the differences among individuals and between cultures. We will
develop an online crowd-sourcing paradigm to test hundreds of participants on a battery of pitch perception
tasks; our hypothesis is that tasks that rely on the same underlying mechanism should correlate. We will also
develop a novel task using singing to probe pitch perception, bypassing the explicit judgments traditionally used
in psychophysical research. Sung responses provide rich analog measures that can be analyzed for both relative
and absolute pitch information. Because singing is a natural human behavior, experiments using singing are well
suited to cross-cultural settings in which participants are less able or willing to perform more traditional
psychophysical tasks. We will compare sung responses of Western musicians and non-musicians, and the
Tsimane’ (an indigenous population of hunter agriculturalists living in the Bolivian Amazon), in order to test for
multiple discrete representations of pitch. Additionally, we will test the same populations on tasks measuring
harmonicity based sound segregation. Studying populations with diverse auditory experiences could help better
characterize mechanisms for perceiving harmonic sounds; this could lead to an increased understanding of pitch
and speech processing deficits in individuals with hearing loss, assisting in the refinement of existing clinical
interventions. This fellowship, along with my research and training plan, will provide me with the foundation for
a successful ca...

## Key facts

- **NIH application ID:** 10020757
- **Project number:** 5F31DC018433-02
- **Recipient organization:** HARVARD MEDICAL SCHOOL
- **Principal Investigator:** Malinda Jeanette McPherson-McNato
- **Activity code:** F31 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $33,790
- **Award type:** 5
- **Project period:** 2019-12-01 → 2022-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10020757

## Citation

> US National Institutes of Health, RePORTER application 10020757, Individual and population differences in the representation of harmonic sounds (5F31DC018433-02). Retrieved via AI Analytics 2026-06-11 from https://api.ai-analytics.org/grant/nih/10020757. Licensed CC0.

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