Vocal imitation is a hallmark of human communication that underlies the capacity to learn to speak and sing. Even so, poor vocal imitation abilities are surprisingly common in the general population, and even expert vocalists cannot match the precision of a musical instrument. Although humans have evolved a greater degree of control over the laryngeal muscles that govern vocal pitch production, this ability may still be underdeveloped compared to control over the articulatory muscles, such as the tongue and lips, volitional control of which emerged earlier in primate evolution. Human participants imitated simple melodies by either singing (i.e., producing pitch with the larynx) or whistling (i.e., producing pitch with the lips and tongue). While participants who sung more precisely also whistled more precisely, sung imitations were less precise than whistled imitations. Furthermore, sung notes were systematically biased towards each individual’s habitual pitch, which may act to conserve muscular effort. The laryngeal muscles that control voice production are under less precise control than the oral muscles that are involved in whistling. This imprecision may be due to the relatively recent evolution of volitional laryngeal-motor control in humans, which may be tuned just well enough for the coarse modulation of vocal-pitch in speech.
Materials
This zipped archive contains a guide to running the experiment described in this manuscript and all of the digital materials to do so. This includes imitation.py which is a python script to conduct the imitation experiments. This script will prompt the user for some input including whether it should run in singing or whistling mode, and MBEA.py which runs a digital implementation of the montreal battery for evaluating amusia. Two subfolders contain all of the auditory stimuli required by both experiments and these folders should be kept in the same directory as the experiment script. Imitation stimuli are labelled according to a western chromatic scale
Experiment.zip
data_archive1
This archive contains raw and processed data for every participant. The archive contains a folder for every participant, which in turn contains subfolders with raw recordings for sung imitations. whistled imitations, and perceptual test scores. Recordings are labeled by the stimulus being imitated and saved along with pitch measurements extracted using praat. Praat utility scripts are also provided to semi-automate pitch measurements. xaa is part 1 of 4 data files that can be recombined in Unix with the following command: cat x* > data.zip. In Windows, the data files can be recombined using the following command from a command prompt: copy /b xaa+xab+xac+xad data.zip.
xaa
data_archive2
This archive contains raw and processed data for every participant. The archive contains a folder for every participant, which in turn contains subfolders with raw recordings for sung imitations. whistled imitations, and perceptual test scores. Recordings are labeled by the stimulus being imitated and saved along with pitch measurements extracted using praat. Praat utility scripts are also provided to semi-automate pitch measurements. xab is part 2 of 4 data files that can be recombined in Unix with the following command: cat x* > data.zip. In Windows, the data files can be recombined using the following command from a command prompt: copy /b xaa+xab+xac+xad data.zip.
xab
data_archive3
This archive contains raw and processed data for every participant. The archive contains a folder for every participant, which in turn contains subfolders with raw recordings for sung imitations. whistled imitations, and perceptual test scores. Recordings are labelled by the stimulus being imitated and saved along with pitch measurements extracted using praat. Praat utility scripts are also provided to semi-automate pitch measurements. xac is part 3 of 4 data files that can be recombined in Unix with the following command: cat x* > data.zip. In Windows, the data files can be recombined using the following command from a command prompt: copy /b xaa+xab+xac+xad data.zip.
xac
data_archive4
This archive contains raw and processed data for every participant. The archive contains a folder for every participant, which in turn contains subfolders with raw recordings for sung imitations. whistled imitations, and perceptual test scores. Recordings are labeled by the stimulus being imitated and saved along with pitch measurements extracted using praat. Praat utility scripts are also provided to semi-automate pitch measurements. xad is part 4 of 4 data files that can be recombined in Unix with the following command: cat x* > data.zip. In Windows, the data files can be recombined using the following command from a command prompt: copy /b xaa+xab+xac+xad data.zip.
xad