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Langehennig-Peristenidou A, Scheumann M. Sex differences in the impact of social relationships on individual vocal signatures in grey mouse lemurs ( Microcebus murinus). Philos Trans R Soc Lond B Biol Sci 2024; 379:20230193. [PMID: 38768201 DOI: 10.1098/rstb.2023.0193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 02/12/2024] [Indexed: 05/22/2024] Open
Abstract
Vocalizations coordinate social interactions between conspecifics by conveying information concerning the individual or group identity of the sender. Social accommodation is a form of vocal learning where social affinity is signalled by converging or diverging vocalizations with those of conspecifics. To investigate whether social accommodation is linked to the social lifestyle of the sender, we investigated sex-specific differences in social accommodation in a dispersed living primate, the grey mouse lemur (Microcebus murinus), where females form stable sleeping groups whereas males live solitarily. We used 482 trill calls of 36 individuals from our captive breeding colony to compare acoustic dissimilarity between individuals with genetic relatedness, social contact time and body weight. Our results showed that female trills become more similar the more time females spend with each other, independent of genetic relationship, suggesting vocal convergence. In contrast, male trills were affected more by genetic than social factors. However, focusing only on socialized males, increasing time as cage partners caused greater divergence in males' trills. Thus, grey mouse lemurs show the capacity for social accommodation, with females converging their trills to signal social closeness to sleeping group partners, whereas males do not adapt or diverge their trills to signal individual distinctiveness. This article is part of the theme issue 'The power of sound: unravelling how acoustic communication shapes group dynamics'.
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Affiliation(s)
| | - Marina Scheumann
- Institute of Zoology, University of Veterinary Medicine Hannover , Hannover 30559, Germany
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2
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Phaniraj N, Brügger RK, Burkart JM. Marmosets mutually compensate for differences in rhythms when coordinating vigilance. PLoS Comput Biol 2024; 20:e1012104. [PMID: 38748738 PMCID: PMC11132515 DOI: 10.1371/journal.pcbi.1012104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 05/28/2024] [Accepted: 04/24/2024] [Indexed: 05/29/2024] Open
Abstract
Synchronization is widespread in animals, and studies have often emphasized how this seemingly complex phenomenon can emerge from very simple rules. However, the amount of flexibility and control that animals might have over synchronization properties, such as the strength of coupling, remains underexplored. Here, we studied how pairs of marmoset monkeys coordinated vigilance while feeding. By modeling them as coupled oscillators, we noted that (1) individual marmosets do not show perfect periodicity in vigilance behaviors, (2) nevertheless, marmoset pairs started to take turns being vigilant over time, a case of anti-phase synchrony, (3) marmosets could couple flexibly; the coupling strength varied with every new joint feeding bout, and (4) marmosets could control the coupling strength; dyads showed increased coupling if they began in a more desynchronized state. Such flexibility and control over synchronization require more than simple interaction rules. Minimally, animals must estimate the current degree of asynchrony and adjust their behavior accordingly. Moreover, the fact that each marmoset is inherently non-periodic adds to the cognitive demand. Overall, our study provides a mathematical framework to investigate the cognitive demands involved in coordinating behaviors in animals, regardless of whether individual behaviors are rhythmic or not.
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Affiliation(s)
- Nikhil Phaniraj
- Institute of Evolutionary Anthropology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
| | - Rahel K. Brügger
- Institute of Evolutionary Anthropology, University of Zurich, Zurich, Switzerland
| | - Judith M. Burkart
- Institute of Evolutionary Anthropology, University of Zurich, Zurich, Switzerland
- Neuroscience Center Zurich, University of Zurich and ETH Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
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3
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Varella TT, Takahashi DY, Ghazanfar AA. Active Sampling in Primate Vocal Interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570161. [PMID: 38106107 PMCID: PMC10723297 DOI: 10.1101/2023.12.05.570161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Active sensing is a behavioral strategy for exploring the environment. In this study, we show that contact vocal behaviors can be an active sensing mechanism that uses sampling to gain information about the social environment, in particular, the vocal behavior of others. With a focus on the realtime vocal interactions of marmoset monkeys, we contrast active sampling to a vocal accommodation framework in which vocalizations are adjusted simply to maximize responses. We conducted simulations of a vocal accommodation and an active sampling policy and compared them with real vocal exchange data. Our findings support active sampling as the best model for marmoset monkey vocal exchanges. In some cases, the active sampling model was even able to predict the distribution of vocal durations for individuals. These results suggest a new function for primate vocal interactions in which they are used by animals to seek information from social environments.
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Affiliation(s)
- Thiago T Varella
- Princeton Neuroscience Institute & Department of Psychology, Princeton University, Princeton NJ 08544, USA
| | - Daniel Y Takahashi
- Brain Institute, Federal University of Rio Grande do Norte (UFRN), Av. Nascimento de Castro, 2155 - Morro Branco, Natal, RN 59056-450, Brasil
| | - Asif A Ghazanfar
- Princeton Neuroscience Institute & Department of Psychology, Princeton University, Princeton NJ 08544, USA
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Madabhushi AJ, Wewhare N, Binwal P, Agarwal V, Krishnan A. Higher-order dialectic variation and syntactic convergence in the complex warble song of budgerigars. J Exp Biol 2023; 226:jeb245678. [PMID: 37732394 DOI: 10.1242/jeb.245678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Accepted: 09/11/2023] [Indexed: 09/22/2023]
Abstract
Dialectic signatures in animal acoustic signals are key in the identification of and association with group members. Complex vocal sequences may also convey information about behavioral state, and may thus vary according to social environment. Some bird species, such as psittaciforms, learn and modify their complex acoustic signals throughout their lives. However, the structure and function of vocal sequences in open-ended vocal learners remains understudied. Here, we examined vocal sequence variation in the warble song of budgerigars, and how these change upon contact between social groups. Budgerigars are open-ended vocal learners which exhibit fission-fusion flock dynamics in the wild. We found that two captive colonies of budgerigars exhibited colony-specific differences in the syntactic structure of their vocal sequences. Individuals from the two colonies differed in the propensity to repeat certain note types, forming repetitive motifs which served as higher-order signatures of colony identity. When the two groups were brought into contact, their vocal sequences converged, and these colony-specific repetitive patterns disappeared, with males from both erstwhile colonies now producing similar sequences with similar syntactic structure. We present data suggesting that the higher-order temporal arrangement of notes/vocal units is modified throughout life by social learning as groups of birds continually associate and dissociate. Our study sheds light on the importance of examining signal structure at multiple levels of organization, and the potential for psittaciform birds as model systems to examine the influence of learning and social environment on acoustic signals.
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Affiliation(s)
- Abhinava Jagan Madabhushi
- Department of Biology, Indian Institute of Science Education and Research (IISER) Pune, Pashan Road, Pune 411008, Maharashtra, India
| | - Nakul Wewhare
- Department of Biology, Indian Institute of Science Education and Research (IISER) Pune, Pashan Road, Pune 411008, Maharashtra, India
| | - Priya Binwal
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur 741246, West Bengal, India
| | - Vaishnavi Agarwal
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhauri 462066, Madhya Pradesh, India
| | - Anand Krishnan
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Bhopal, Bhauri 462066, Madhya Pradesh, India
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Phaniraj N, Wierucka K, Zürcher Y, Burkart JM. Who is calling? Optimizing source identification from marmoset vocalizations with hierarchical machine learning classifiers. J R Soc Interface 2023; 20:20230399. [PMID: 37848054 PMCID: PMC10581777 DOI: 10.1098/rsif.2023.0399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 09/25/2023] [Indexed: 10/19/2023] Open
Abstract
With their highly social nature and complex vocal communication system, marmosets are important models for comparative studies of vocal communication and, eventually, language evolution. However, our knowledge about marmoset vocalizations predominantly originates from playback studies or vocal interactions between dyads, and there is a need to move towards studying group-level communication dynamics. Efficient source identification from marmoset vocalizations is essential for this challenge, and machine learning algorithms (MLAs) can aid it. Here we built a pipeline capable of plentiful feature extraction, meaningful feature selection, and supervised classification of vocalizations of up to 18 marmosets. We optimized the classifier by building a hierarchical MLA that first learned to determine the sex of the source, narrowed down the possible source individuals based on their sex and then determined the source identity. We were able to correctly identify the source individual with high precisions (87.21%-94.42%, depending on call type, and up to 97.79% after the removal of twins from the dataset). We also examine the robustness of identification across varying sample sizes. Our pipeline is a promising tool not only for source identification from marmoset vocalizations but also for analysing vocalizations of other species.
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Affiliation(s)
- Nikhil Phaniraj
- Institute of Evolutionary Anthropology (IEA), University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich (ZNZ), University of Zurich and ETH Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Department of Biology, Indian Institute of Science Education and Research (IISER) Pune, Dr. Homi Bhabha Road, Pune 411008, India
| | - Kaja Wierucka
- Institute of Evolutionary Anthropology (IEA), University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Behavioral Ecology & Sociobiology Unit, German Primate Center, Leibniz Institute for Primate Research, Kellnerweg 4, 37077 Göttingen, Germany
| | - Yvonne Zürcher
- Institute of Evolutionary Anthropology (IEA), University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
| | - Judith M. Burkart
- Institute of Evolutionary Anthropology (IEA), University of Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Neuroscience Center Zurich (ZNZ), University of Zurich and ETH Zurich, Winterthurerstrasse 190, 8057 Zürich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Affolternstrasse 56, 8050 Zürich, Switzerland
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Pellegrino E, Dellwo V. Speakers are more cooperative and less individual when interacting in larger group sizes. Front Psychol 2023; 14:1145572. [PMID: 37342649 PMCID: PMC10277674 DOI: 10.3389/fpsyg.2023.1145572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 05/03/2023] [Indexed: 06/23/2023] Open
Abstract
Introduction Cooperation, acoustically signaled through vocal convergence, is facilitated when group members are more similar. Excessive vocal convergence may, however, weaken individual recognizability. This study aimed to explore whether constraints to convergence can arise in circumstances where interlocutors need to enhance their vocal individuality. Therefore, we tested the effects of group size (3 and 5 interactants) on vocal convergence and individualization in a social communication scenario in which individual recognition by voice is at stake. Methods In an interactive game, players had to recognize each other through their voices while solving a cooperative task online. The vocal similarity was quantified through similarities in speaker i-vectors obtained through probabilistic linear discriminant analysis (PLDA). Speaker recognition performance was measured through the system Equal Error Rate (EER). Results Vocal similarity between-speakers increased with a larger group size which indicates a higher cooperative vocal behavior. At the same time, there was an increase in EER for the same speakers between the smaller and the larger group size, meaning a decrease in overall recognition performance. Discussion The decrease in vocal individualization in the larger group size suggests that ingroup cooperation and social cohesion conveyed through acoustic convergence have priority over individualization in larger groups of unacquainted speakers.
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Burkart JM, Adriaense JEC, Brügger RK, Miss FM, Wierucka K, van Schaik CP. A convergent interaction engine: vocal communication among marmoset monkeys. Philos Trans R Soc Lond B Biol Sci 2022; 377:20210098. [PMID: 35876206 PMCID: PMC9315454 DOI: 10.1098/rstb.2021.0098] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 01/26/2022] [Indexed: 09/14/2023] Open
Abstract
To understand the primate origins of the human interaction engine, it is worthwhile to focus not only on great apes but also on callitrichid monkeys (marmosets and tamarins). Like humans, but unlike great apes, callitrichids are cooperative breeders, and thus habitually engage in coordinated joint actions, for instance when an infant is handed over from one group member to another. We first explore the hypothesis that these habitual cooperative interactions, the marmoset interactional ethology, are supported by the same key elements as found in the human interaction engine: mutual gaze (during joint action), turn-taking, volubility, as well as group-wide prosociality and trust. Marmosets show clear evidence of these features. We next examine the prediction that, if such an interaction engine can indeed give rise to more flexible communication, callitrichids may also possess elaborate communicative skills. A review of marmoset vocal communication confirms unusual abilities in these small primates: high volubility and large vocal repertoires, vocal learning and babbling in immatures, and voluntary usage and control. We end by discussing how the adoption of cooperative breeding during human evolution may have catalysed language evolution by adding these convergent consequences to the great ape-like cognitive system of our hominin ancestors. This article is part of the theme issue 'Revisiting the human 'interaction engine': comparative approaches to social action coordination'.
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Affiliation(s)
- J. M. Burkart
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution ISLE, University of Zurich, Affolternstrasse 56, 8050 Zurich, Switzerland
| | - J. E. C. Adriaense
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - R. K. Brügger
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - F. M. Miss
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - K. Wierucka
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - C. P. van Schaik
- Department of Anthropology, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution ISLE, University of Zurich, Affolternstrasse 56, 8050 Zurich, Switzerland
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Zuberbühler K, León J, Deshpande A, Quintero F. Socially scripted vocal learning in primates. Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2022.101153] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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9
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Selection levels on vocal individuality: strategic use or byproduct. Curr Opin Behav Sci 2022. [DOI: 10.1016/j.cobeha.2022.101140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Schick J, Fryns C, Wegdell F, Laporte M, Zuberbühler K, van Schaik CP, Townsend SW, Stoll S. The function and evolution of child-directed communication. PLoS Biol 2022; 20:e3001630. [PMID: 35522717 PMCID: PMC9116647 DOI: 10.1371/journal.pbio.3001630] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Revised: 05/18/2022] [Indexed: 11/20/2022] Open
Abstract
Humans communicate with small children in unusual and highly conspicuous ways (child-directed communication (CDC)), which enhance social bonding and facilitate language acquisition. CDC-like inputs are also reported for some vocally learning animals, suggesting similar functions in facilitating communicative competence. However, adult great apes, our closest living relatives, rarely signal to their infants, implicating communication surrounding the infant as the main input for infant great apes and early humans. Given cross-cultural variation in the amount and structure of CDC, we suggest that child-surrounding communication (CSC) provides essential compensatory input when CDC is less prevalent-a paramount topic for future studies.
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Affiliation(s)
- Johanna Schick
- Department of Comparative Language Science, University of Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
| | - Caroline Fryns
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
- Department of Comparative Cognition, University of Neuchatel, Neuchatel, Switzerland
| | - Franziska Wegdell
- Department of Comparative Language Science, University of Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
| | - Marion Laporte
- Histoire naturelle de l’Homme préhistorique, UMR 7194, PaleoFED, Muséum National d’Histoire Naturelle, Paris, France
- Institut des Sciences du Calcul et des Données, Sorbonne Université, Paris, France
| | - Klaus Zuberbühler
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
- Department of Comparative Cognition, University of Neuchatel, Neuchatel, Switzerland
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
| | - Carel P. van Schaik
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
- Department of Anthropology, University of Zurich, Zurich, Switzerland
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
| | - Simon W. Townsend
- Department of Comparative Language Science, University of Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
- Department of Psychology, University of Warwick, Warwick, United Kingdom
| | - Sabine Stoll
- Department of Comparative Language Science, University of Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution (ISLE), University of Zurich, Zurich, Switzerland
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Adret P. Developmental Plasticity in Primate Coordinated Song: Parallels and Divergences With Duetting Songbirds. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.862196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Homeothermic animals (birds and mammals) are prime model systems for investigating the developmental plasticity and neural mechanisms of vocal duetting, a cooperative acoustic signal that prevails in family-living and pair-bonded species including humans. This review focuses on the nature of this trait and its nurturing during ontogeny and extending into adulthood. I begin by outlining the underpinning concepts of duet codes and pair-specific answering rules as used by birds to develop their learned coordinated song, driven by a complex interaction between self-generated and socially mediated auditory feedback. The more tractable avian model of duetting helps identify research gaps in singing primates that also use duetting as a type of intraspecific vocal interaction. Nevertheless, it has become clear that primate coordinated song—whether overlapping or antiphonal—is subject to some degree of vocal flexibility. This is reflected in the ability of lesser apes, titi monkeys, tarsiers, and lemurs to adjust the structure and timing of their calls through (1) social influence, (2) coordinated duetting both before and after mating, (3) the repair of vocal mistakes, (4) the production of heterosexual song early in life, (5) vocal accommodation in call rhythm, (6) conditioning, and (7) innovation. Furthermore, experimental work on the neural underpinnings of avian and mammalian antiphonal duets point to a hierarchical (cortico-subcortical) control mechanism that regulates, via inhibition, the temporal segregation of rapid vocal exchanges. I discuss some weaknesses in this growing field of research and highlight prospective avenues for future investigation.
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