Morphing rhesus monkey vocalizations

Chakladar, Subhojit; Logothetis, Nikos K.; Petkov, Christopher I.

doi:10.1016/j.jneumeth.2007.12.023

Cited by 14 publications

(14 citation statements)

References 25 publications

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“…Previously, the vocal tract lengths of rhesus monkeys were increased or decreased virtually using this software ( Ghazanfar et al, 2007 ). Chakladar et al (2008) demonstrated that the vocalizations of different macaque individuals could be morphed using this software, and the quality of the morphs was evaluated by human listeners. In the present study, the time taken by both monkeys and humans to release the lever increased gradually with an increase in the morph proportion ( Fig.…”

Section: Discussionmentioning

confidence: 99%

Acoustic characteristics used by Japanese macaques for individual discrimination

Furuyama

Kobayasi

Riquimaroux

2017

Journal of Experimental Biology

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The vocalizations of primates contain information about speaker individuality. Many primates, including humans, are able to distinguish conspecifics based solely on vocalizations. The purpose of this study was to investigate the acoustic characteristics used by Japanese macaques in individual vocal discrimination. Furthermore, we tested human subjects using monkey vocalizations to evaluate species specificity with respect to such discriminations. Two monkeys and five humans were trained to discriminate the coo calls of two unfamiliar monkeys. We created a stimulus continuum between the vocalizations of the two monkeys as a set of probe stimuli (whole morph). We also created two sets of continua in which only one acoustic parameter, fundamental frequency (f0) or vocal tract characteristic (VTC), was changed from the coo call of one monkey to that of another while the other acoustic feature remained the same (f0 morph and VTC morph, respectively). According to the results, the reaction times both of monkeys and humans were correlated with the morph proportion under the whole morph and f0 morph conditions. The reaction time to the VTC morph was correlated with the morph proportion in both monkeys, whereas the reaction time in humans, on average, was not correlated with morph proportion. Japanese monkeys relied more consistently on VTC than did humans for discriminating monkey vocalizations. Our results support the idea that the auditory system of primates is specialized for processing conspecific vocalizations and suggest that VTC is a significant acoustic feature used by Japanese macaques to discriminate conspecific vocalizations.

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Section: Discussionmentioning

confidence: 99%

Acoustic characteristics used by Japanese macaques for individual discrimination

Furuyama

Kobayasi

Riquimaroux

2017

Journal of Experimental Biology

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“…A popular choice for such work is to use the STRAIGHT algorithm, which can morph broadly similar sounds on the basis of several manually specified landmarks that identify corresponding parts of the two spectrograms (Kawahara et al, 1999). For example, this technique was used to demonstrate categorical perception of macaque vocalizations by human listeners (Chakladar, Logothetis, & Petkov, 2008), to study acoustic features enabling individual recognition in macaques (Furuyama, Kobayasi, & Riquimaroux, 2017), and to prepare morphs of emotional vocalizations for a neuroimaging study (Salvia et al, 2014).…”

Section: How Does Soundgen Compare To the Alternatives?mentioning

confidence: 99%

Soundgen: An open-source tool for synthesizing nonverbal vocalizations

Anikin

2018

Behav Res

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Voice synthesis is a useful method for investigating the communicative role of different acoustic features. Although many text-tospeech systems are available, researchers of human nonverbal vocalizations and bioacousticians may profit from a dedicated simple tool for synthesizing and manipulating natural-sounding vocalizations. Soundgen (https://CRAN.R-project.org/package=soundgen) is an open-source R package that synthesizes nonverbal vocalizations based on meaningful acoustic parameters, which can be specified from the command line or in an interactive app. This tool was validated by comparing the perceived emotion, valence, arousal, and authenticity of 60 recorded human nonverbal vocalizations (screams, moans, laughs, and so on) and their approximate synthetic reproductions. Each synthetic sound was created by manually specifying only a small number of high-level control parameters, such as syllable length and a few anchors for the intonation contour. Nevertheless, the valence and arousal ratings of synthetic sounds were similar to those of the original recordings, and the authenticity ratings were comparable, maintaining parity with the originals for less complex vocalizations. Manipulating the precise acoustic characteristics of synthetic sounds may shed light on the salient predictors of emotion in the human voice. More generally, soundgen may prove useful for any studies that require precise control over the acoustic features of nonspeech sounds, including research on animal vocalizations and auditory perception.

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“…Although different pools of neurons may be differentially sensitive to specific acoustic features (Averbeck and Romanski, 2004, 2006; Freeman et al, 2013; Kusmierek et al, 2012), our data could not identify any such relationship nor could we identify one in the literature. To address this question, AL activity should be recorded in response to synthetic vocalizations (Chakladar et al, 2008; DiMattina and Wang, 2006) that allow for systematic manipulations of these acoustic features.…”

Section: Discussionmentioning

confidence: 99%

Natural variability in species-specific vocalizations constrains behavior and neural activity

et al. 2014

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A listener’s capacity to discriminate between sounds is related to the amount of acoustic variability that exists between these sounds. However, a full understanding of how this natural variability impacts neural activity and behavior is lacking. Here, we tested monkeys’ ability to discriminate between different utterances of vocalizations from the same acoustic class (i.e., coos and grunts), while neural activity was simultaneously recorded in the anterolateral belt region (AL) of the auditory cortex, a brain region that is a part of a pathway that mediates auditory perception. Monkeys could discriminate between coos better than they could discriminate between grunts. We also found AL activity was more informative about different coos than different grunts. This difference could be attributed, in part, to our finding that coos had more acoustic variability than grunts. Thus, intrinsic acoustic variability constrained the discriminability of AL spike trains and the ability of rhesus monkeys to discriminate between vocalizations.

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Morphing rhesus monkey vocalizations

Cited by 14 publications

References 25 publications

Acoustic characteristics used by Japanese macaques for individual discrimination

Acoustic characteristics used by Japanese macaques for individual discrimination

Soundgen: An open-source tool for synthesizing nonverbal vocalizations

Natural variability in species-specific vocalizations constrains behavior and neural activity

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