1
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Koparkar A, Warren TL, Charlesworth JD, Shin S, Brainard MS, Veit L. Lesions in a songbird vocal circuit increase variability in song syntax. eLife 2024; 13:RP93272. [PMID: 38635312 PMCID: PMC11026095 DOI: 10.7554/elife.93272] [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] [Indexed: 04/19/2024] Open
Abstract
Complex skills like speech and dance are composed of ordered sequences of simpler elements, but the neuronal basis for the syntactic ordering of actions is poorly understood. Birdsong is a learned vocal behavior composed of syntactically ordered syllables, controlled in part by the songbird premotor nucleus HVC (proper name). Here, we test whether one of HVC's recurrent inputs, mMAN (medial magnocellular nucleus of the anterior nidopallium), contributes to sequencing in adult male Bengalese finches (Lonchura striata domestica). Bengalese finch song includes several patterns: (1) chunks, comprising stereotyped syllable sequences; (2) branch points, where a given syllable can be followed probabilistically by multiple syllables; and (3) repeat phrases, where individual syllables are repeated variable numbers of times. We found that following bilateral lesions of mMAN, acoustic structure of syllables remained largely intact, but sequencing became more variable, as evidenced by 'breaks' in previously stereotyped chunks, increased uncertainty at branch points, and increased variability in repeat numbers. Our results show that mMAN contributes to the variable sequencing of vocal elements in Bengalese finch song and demonstrate the influence of recurrent projections to HVC. Furthermore, they highlight the utility of species with complex syntax in investigating neuronal control of ordered sequences.
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Affiliation(s)
- Avani Koparkar
- Neurobiology of Vocal Communication, Institute for Neurobiology, University of TübingenTübingenGermany
| | - Timothy L Warren
- Howard Hughes Medical Institute and Center for Integrative Neuroscience, University of California San FranciscoSan FranciscoUnited States
- Departments of Horticulture and Integrative Biology, Oregon State UniversityCorvallisUnited States
| | - Jonathan D Charlesworth
- Howard Hughes Medical Institute and Center for Integrative Neuroscience, University of California San FranciscoSan FranciscoUnited States
| | - Sooyoon Shin
- Howard Hughes Medical Institute and Center for Integrative Neuroscience, University of California San FranciscoSan FranciscoUnited States
| | - Michael S Brainard
- Howard Hughes Medical Institute and Center for Integrative Neuroscience, University of California San FranciscoSan FranciscoUnited States
| | - Lena Veit
- Neurobiology of Vocal Communication, Institute for Neurobiology, University of TübingenTübingenGermany
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2
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Youngblood M. Language-like efficiency and structure in house finch song. Proc Biol Sci 2024; 291:20240250. [PMID: 38565151 PMCID: PMC10987240 DOI: 10.1098/rspb.2024.0250] [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: 01/29/2023] [Accepted: 03/06/2024] [Indexed: 04/04/2024] Open
Abstract
Communication needs to be complex enough to be functional while minimizing learning and production costs. Recent work suggests that the vocalizations and gestures of some songbirds, cetaceans and great apes may conform to linguistic laws that reflect this trade-off between efficiency and complexity. In studies of non-human communication, though, clustering signals into types cannot be done a priori, and decisions about the appropriate grain of analysis may affect statistical signals in the data. The aim of this study was to assess the evidence for language-like efficiency and structure in house finch (Haemorhous mexicanus) song across three levels of granularity in syllable clustering. The results show strong evidence for Zipf's rank-frequency law, Zipf's law of abbreviation and Menzerath's law. Additional analyses show that house finch songs have small-world structure, thought to reflect systematic structure in syntax, and the mutual information decay of sequences is consistent with a combination of Markovian and hierarchical processes. These statistical patterns are robust across three levels of granularity in syllable clustering, pointing to a limited form of scale invariance. In sum, it appears that house finch song has been shaped by pressure for efficiency, possibly to offset the costs of female preferences for complexity.
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Affiliation(s)
- Mason Youngblood
- Minds and Traditions Research Group, Max Planck Institute for Geoanthropology, Jena, Thüringen, Germany
- Institute for Advanced Computational Science, Stony Brook University, Stony Brook, NY, USA
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3
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Watson SK, Mine JG, O’Neill LG, Mueller JL, Russell AF, Townsend SW. Cognitive constraints on vocal combinatoriality in a social bird. iScience 2023; 26:106977. [PMID: 37332672 PMCID: PMC10275715 DOI: 10.1016/j.isci.2023.106977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 11/29/2022] [Accepted: 05/24/2023] [Indexed: 06/20/2023] Open
Abstract
A critical component of language is the ability to recombine sounds into larger structures. Although animals also reuse sound elements across call combinations to generate meaning, examples are generally limited to pairs of distinct elements, even when repertoires contain sufficient sounds to generate hundreds of combinations. This combinatoriality might be constrained by the perceptual-cognitive demands of disambiguating between complex sound sequences that share elements. We test this hypothesis by probing the capacity of chestnut-crowned babblers to process combinations of two versus three distinct acoustic elements. We found babblers responded quicker and for longer toward playbacks of recombined versus familiar bi-element sequences, but no evidence of differential responses toward playbacks of recombined versus familiar tri-element sequences, suggesting a cognitively prohibitive jump in processing demands. We propose that overcoming constraints in the ability to process increasingly complex combinatorial signals was necessary for the productive combinatoriality that is characteristic of language to emerge.
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Affiliation(s)
- Stuart K. Watson
- Department of Comparative Language Science, University of Zurich, Zurich, Switzerland
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution, Zurich, Switzerland
| | - Joseph G. Mine
- Department of Comparative Language Science, University of Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution, Zurich, Switzerland
- Faculty of Environment, Science and Economy, University of Exeter, Penryn, Cornwall TR10 9FE, UK
| | - Louis G. O’Neill
- Faculty of Environment, Science and Economy, University of Exeter, Penryn, Cornwall TR10 9FE, UK
- Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109 Australia
- Fowlers Gap Arid Zone Research Station, School of Biological, Earth & Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | | | - Andrew F. Russell
- Faculty of Environment, Science and Economy, University of Exeter, Penryn, Cornwall TR10 9FE, UK
- Institute of Linguistics, University of Vienna, Vienna, Austria
- Fowlers Gap Arid Zone Research Station, School of Biological, Earth & Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
| | - Simon W. Townsend
- Department of Comparative Language Science, University of Zurich, Zurich, Switzerland
- Center for the Interdisciplinary Study of Language Evolution, Zurich, Switzerland
- Department of Psychology, University of Warwick, Coventry, UK
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4
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Éltető N, Nemeth D, Janacsek K, Dayan P. Tracking human skill learning with a hierarchical Bayesian sequence model. PLoS Comput Biol 2022; 18:e1009866. [PMID: 36449550 PMCID: PMC9744313 DOI: 10.1371/journal.pcbi.1009866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 12/12/2022] [Accepted: 10/31/2022] [Indexed: 12/03/2022] Open
Abstract
Humans can implicitly learn complex perceptuo-motor skills over the course of large numbers of trials. This likely depends on our becoming better able to take advantage of ever richer and temporally deeper predictive relationships in the environment. Here, we offer a novel characterization of this process, fitting a non-parametric, hierarchical Bayesian sequence model to the reaction times of human participants' responses over ten sessions, each comprising thousands of trials, in a serial reaction time task involving higher-order dependencies. The model, adapted from the domain of language, forgetfully updates trial-by-trial, and seamlessly combines predictive information from shorter and longer windows onto past events, weighing the windows proportionally to their predictive power. As the model implies a posterior over window depths, we were able to determine how, and how many, previous sequence elements influenced individual participants' internal predictions, and how this changed with practice. Already in the first session, the model showed that participants had begun to rely on two previous elements (i.e., trigrams), thereby successfully adapting to the most prominent higher-order structure in the task. The extent to which local statistical fluctuations in trigram frequency influenced participants' responses waned over subsequent sessions, as participants forgot the trigrams less and evidenced skilled performance. By the eighth session, a subset of participants shifted their prior further to consider a context deeper than two previous elements. Finally, participants showed resistance to interference and slow forgetting of the old sequence when it was changed in the final sessions. Model parameters for individual participants covaried appropriately with independent measures of working memory and error characteristics. In sum, the model offers the first principled account of the adaptive complexity and nuanced dynamics of humans' internal sequence representations during long-term implicit skill learning.
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Affiliation(s)
- Noémi Éltető
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- * E-mail:
| | - Dezső Nemeth
- Lyon Neuroscience Research Center, Université de Lyon, Lyon, France
- Institute of Psychology, ELTE Eötvös Loránd University, Budapest, Hungary
- Institute of Cognitive Neuroscience and Psychology, Research Centre for Natural Sciences, Budapest, Hungary
| | - Karolina Janacsek
- Institute of Psychology, ELTE Eötvös Loránd University, Budapest, Hungary
- Centre for Thinking and Learning, Institute for Lifecourse Development, Universtiy of Greenwich, London, United Kingdom
| | - Peter Dayan
- Max Planck Institute for Biological Cybernetics, Tübingen, Germany
- University of Tübingen, Tübingen, Germany
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5
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Measuring context dependency in birdsong using artificial neural networks. PLoS Comput Biol 2021; 17:e1009707. [PMID: 34962915 PMCID: PMC8746767 DOI: 10.1371/journal.pcbi.1009707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 01/10/2022] [Accepted: 12/01/2021] [Indexed: 11/19/2022] Open
Abstract
Context dependency is a key feature in sequential structures of human language, which requires reference between words far apart in the produced sequence. Assessing how long the past context has an effect on the current status provides crucial information to understand the mechanism for complex sequential behaviors. Birdsongs serve as a representative model for studying the context dependency in sequential signals produced by non-human animals, while previous reports were upper-bounded by methodological limitations. Here, we newly estimated the context dependency in birdsongs in a more scalable way using a modern neural-network-based language model whose accessible context length is sufficiently long. The detected context dependency was beyond the order of traditional Markovian models of birdsong, but was consistent with previous experimental investigations. We also studied the relation between the assumed/auto-detected vocabulary size of birdsong (i.e., fine- vs. coarse-grained syllable classifications) and the context dependency. It turned out that the larger vocabulary (or the more fine-grained classification) is assumed, the shorter context dependency is detected.
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6
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Sainburg T, Gentner TQ. Toward a Computational Neuroethology of Vocal Communication: From Bioacoustics to Neurophysiology, Emerging Tools and Future Directions. Front Behav Neurosci 2021; 15:811737. [PMID: 34987365 PMCID: PMC8721140 DOI: 10.3389/fnbeh.2021.811737] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 11/29/2021] [Indexed: 11/23/2022] Open
Abstract
Recently developed methods in computational neuroethology have enabled increasingly detailed and comprehensive quantification of animal movements and behavioral kinematics. Vocal communication behavior is well poised for application of similar large-scale quantification methods in the service of physiological and ethological studies. This review describes emerging techniques that can be applied to acoustic and vocal communication signals with the goal of enabling study beyond a small number of model species. We review a range of modern computational methods for bioacoustics, signal processing, and brain-behavior mapping. Along with a discussion of recent advances and techniques, we include challenges and broader goals in establishing a framework for the computational neuroethology of vocal communication.
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Affiliation(s)
- Tim Sainburg
- Department of Psychology, University of California, San Diego, La Jolla, CA, United States
- Center for Academic Research & Training in Anthropogeny, University of California, San Diego, La Jolla, CA, United States
| | - Timothy Q. Gentner
- Department of Psychology, University of California, San Diego, La Jolla, CA, United States
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, United States
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, United States
- Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA, United States
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7
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Sawant S, Arvind C, Joshi V, Robin VV. Spectrogram cross‐correlation can be used to measure the complexity of bird vocalizations. Methods Ecol Evol 2021. [DOI: 10.1111/2041-210x.13765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Suyash Sawant
- Department of Biology Indian Institute of Science Education and Research (IISER) Tirupati Tirupati India
| | - Chiti Arvind
- Department of Biology Indian Institute of Science Education and Research (IISER) Tirupati Tirupati India
| | - Viral Joshi
- Department of Biology Indian Institute of Science Education and Research (IISER) Tirupati Tirupati India
| | - V. V. Robin
- Department of Biology Indian Institute of Science Education and Research (IISER) Tirupati Tirupati India
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8
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Sainburg T, Thielk M, Gentner TQ. Finding, visualizing, and quantifying latent structure across diverse animal vocal repertoires. PLoS Comput Biol 2020; 16:e1008228. [PMID: 33057332 PMCID: PMC7591061 DOI: 10.1371/journal.pcbi.1008228] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 10/27/2020] [Accepted: 08/08/2020] [Indexed: 12/15/2022] Open
Abstract
Animals produce vocalizations that range in complexity from a single repeated call to hundreds of unique vocal elements patterned in sequences unfolding over hours. Characterizing complex vocalizations can require considerable effort and a deep intuition about each species' vocal behavior. Even with a great deal of experience, human characterizations of animal communication can be affected by human perceptual biases. We present a set of computational methods for projecting animal vocalizations into low dimensional latent representational spaces that are directly learned from the spectrograms of vocal signals. We apply these methods to diverse datasets from over 20 species, including humans, bats, songbirds, mice, cetaceans, and nonhuman primates. Latent projections uncover complex features of data in visually intuitive and quantifiable ways, enabling high-powered comparative analyses of vocal acoustics. We introduce methods for analyzing vocalizations as both discrete sequences and as continuous latent variables. Each method can be used to disentangle complex spectro-temporal structure and observe long-timescale organization in communication.
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Affiliation(s)
- Tim Sainburg
- Department of Psychology, University of California, San Diego, La Jolla, CA, USA
- Center for Academic Research & Training in Anthropogeny, University of California, San Diego, La Jolla, CA, USA
| | - Marvin Thielk
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
| | - Timothy Q. Gentner
- Department of Psychology, University of California, San Diego, La Jolla, CA, USA
- Neurosciences Graduate Program, University of California, San Diego, La Jolla, CA, USA
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
- Kavli Institute for Brain and Mind, University of California, San Diego, La Jolla, CA, USA
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9
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Mizuhara T, Okanoya K. Do songbirds hear songs syllable by syllable? Behav Processes 2020; 174:104089. [PMID: 32105758 DOI: 10.1016/j.beproc.2020.104089] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 01/30/2020] [Accepted: 02/23/2020] [Indexed: 12/29/2022]
Abstract
Songbirds as vocal learners have been one of the most popular model species to investigate the biological prerequisite to human language. Their songs consist of syllables, which appear as pulse trains in sound spectrograms. When describing the song sequence, researchers consider the syllable to be the unit of the song. Moreover, artificial grammar learning studies asking whether songbirds recognize structural regularities observed in human language often design stimuli using song syllables as components. However, whether syllables are perceptual units is yet to be determined. We found that Bengalese finches, a species of songbird, responded significantly less to one specific syllable when it was temporally placed close to the preceding syllable. The proximity, or silent interval was within the range of what is produced in the natural songs of both Bengalese and zebra finches, and what has been used in other artificial grammar learning studies using zebra finches. Our results suggest the need for a reinterpretation of the description of birdsong structure and of previous artificial grammar learning studies.
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Affiliation(s)
- Tomoko Mizuhara
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan.
| | - Kazuo Okanoya
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro, Tokyo 153-8902, Japan.
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10
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Statistical learning for vocal sequence acquisition in a songbird. Sci Rep 2020; 10:2248. [PMID: 32041978 PMCID: PMC7010765 DOI: 10.1038/s41598-020-58983-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 01/17/2020] [Indexed: 01/31/2023] Open
Abstract
Birdsong is a learned communicative behavior that consists of discrete acoustic elements (“syllables”) that are sequenced in a controlled manner. While the learning of the acoustic structure of syllables has been extensively studied, relatively little is known about sequence learning in songbirds. Statistical learning could contribute to the acquisition of vocal sequences, and we investigated the nature and extent of sequence learning at various levels of song organization in the Bengalese finch, Lonchura striata var. domestica. We found that, under semi-natural conditions, pupils (sons) significantly reproduced the sequence statistics of their tutor’s (father’s) songs at multiple levels of organization (e.g., syllable repertoire, prevalence, and transitions). For example, the probability of syllable transitions at “branch points” (relatively complex sequences that are followed by multiple types of transitions) were significantly correlated between the songs of tutors and pupils. We confirmed the contribution of learning to sequence similarities between fathers and sons by experimentally tutoring juvenile Bengalese finches with the songs of unrelated tutors. We also discovered that the extent and fidelity of sequence similarities between tutors and pupils were significantly predicted by the prevalence of sequences in the tutor’s song and that distinct types of sequence modifications (e.g., syllable additions or deletions) followed distinct patterns. Taken together, these data provide compelling support for the role of statistical learning in vocal production learning and identify factors that could modulate the extent of vocal sequence learning.
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11
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Sainburg T, Theilman B, Thielk M, Gentner TQ. Parallels in the sequential organization of birdsong and human speech. Nat Commun 2019; 10:3636. [PMID: 31406118 PMCID: PMC6690877 DOI: 10.1038/s41467-019-11605-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 07/09/2019] [Indexed: 11/08/2022] Open
Abstract
Human speech possesses a rich hierarchical structure that allows for meaning to be altered by words spaced far apart in time. Conversely, the sequential structure of nonhuman communication is thought to follow non-hierarchical Markovian dynamics operating over only short distances. Here, we show that human speech and birdsong share a similar sequential structure indicative of both hierarchical and Markovian organization. We analyze the sequential dynamics of song from multiple songbird species and speech from multiple languages by modeling the information content of signals as a function of the sequential distance between vocal elements. Across short sequence-distances, an exponential decay dominates the information in speech and birdsong, consistent with underlying Markovian processes. At longer sequence-distances, the decay in information follows a power law, consistent with underlying hierarchical processes. Thus, the sequential organization of acoustic elements in two learned vocal communication signals (speech and birdsong) shows functionally equivalent dynamics, governed by similar processes.
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Affiliation(s)
- Tim Sainburg
- Department of Psychology, University of California, UC San Diego, La Jolla, CA, 92093, USA
- Center for Academic Research & Training in Anthropogeny, UC San Diego, La Jolla, CA, 92093, USA
| | - Brad Theilman
- Neurosciences Graduate Program, University of California, UC San Diego, La Jolla, CA, 92093, USA
| | - Marvin Thielk
- Neurosciences Graduate Program, University of California, UC San Diego, La Jolla, CA, 92093, USA
| | - Timothy Q Gentner
- Department of Psychology, University of California, UC San Diego, La Jolla, CA, 92093, USA.
- Neurosciences Graduate Program, University of California, UC San Diego, La Jolla, CA, 92093, USA.
- Neurobiology Section, Division of Biological Sciences, UC San Diego, La Jolla, CA, 92093, USA.
- Kavli Institute for Brain and Mind, La Jolla, CA, 92093, USA.
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12
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Morita T, Koda H. Superregular grammars do not provide additional explanatory power but allow for a compact analysis of animal song. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190139. [PMID: 31417719 PMCID: PMC6689648 DOI: 10.1098/rsos.190139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 06/14/2019] [Indexed: 06/10/2023]
Abstract
A pervasive belief with regard to the differences between human language and animal vocal sequences (song) is that they belong to different classes of computational complexity, with animal song belonging to regular languages, whereas human language is superregular. This argument, however, lacks empirical evidence since superregular analyses of animal song are understudied. The goal of this paper is to perform a superregular analysis of animal song, using data from gibbons as a case study, and demonstrate that a superregular analysis can be effectively used with non-human data. A key finding is that a superregular analysis does not increase explanatory power but rather provides for compact analysis: fewer grammatical rules are necessary once superregularity is allowed. This pattern is analogous to a previous computational analysis of human language, and accordingly, the null hypothesis, that human language and animal song are governed by the same type of grammatical systems, cannot be rejected.
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Affiliation(s)
- T. Morita
- Primate Research Institute, Kyoto University, 41-2 Kanrin, Inuyama, Aichi 484-8506, Japan
| | - H. Koda
- Primate Research Institute, Kyoto University, 41-2 Kanrin, Inuyama, Aichi 484-8506, Japan
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13
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Drosophila melanogaster grooming possesses syntax with distinct rules at different temporal scales. PLoS Comput Biol 2019; 15:e1007105. [PMID: 31242178 PMCID: PMC6594582 DOI: 10.1371/journal.pcbi.1007105] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 05/13/2019] [Indexed: 12/26/2022] Open
Abstract
Mathematical modeling of behavioral sequences yields insight into the rules and mechanisms underlying sequence generation. Grooming in Drosophila melanogaster is characterized by repeated execution of distinct, stereotyped actions in variable order. Experiments demonstrate that, following stimulation by an irritant, grooming progresses gradually from an early phase dominated by anterior cleaning to a later phase with increased walking and posterior cleaning. We also observe that, at an intermediate temporal scale, there is a strong relationship between the amount of time spent performing body-directed grooming actions and leg-directed actions. We then develop a series of data-driven Markov models that isolate and identify the behavioral features governing transitions between individual grooming bouts. We identify action order as the primary driver of probabilistic, but non-random, syntax structure, as has previously been identified. Subsequent models incorporate grooming bout duration, which also contributes significantly to sequence structure. Our results show that, surprisingly, the syntactic rules underlying probabilistic grooming transitions possess action duration-dependent structure, suggesting that sensory input-independent mechanisms guide grooming behavior at short time scales. Finally, the inclusion of a simple rule that modifies grooming transition probabilities over time yields a generative model that recapitulates the key features of observed grooming sequences at several time scales. These discoveries suggest that sensory input guides action selection by modulating internally generated dynamics. Additionally, the discovery of these principles governing grooming in D. melanogaster demonstrates the utility of incorporating temporal information when characterizing the syntax of behavioral sequences. Analysis of temporally rich behavioral sequences provides a quantitative description of the rules underlying their generation. Drosophila melanogaster grooming behavior consists of many complex sequences involving repetitions of well-characterized actions. In this paper, we leverage advances in machine vision to automatically annotate over 40 hours of video data of flies covered in dust and develop mathematical models that reveal the existence of syntax in D. melanogaster grooming. We find that sequence organization depends on grooming action identity, as has been well-established, and, more surprisingly, grooming action duration. The discovery of duration-dependent action selection leads us to conclude that, although sensory input informs grooming decisions on long time scales, internal dynamics also guide individual transitions between grooming actions. Therefore, incorporating action duration into our models allows us to uncover multi-scale temporal dynamics that suggest the existence of neural circuits dedicated to partially sensory-independent decision-making. Our approach highlights the importance of incorporating temporal information into sequential models, as doing so reveals the relative contributions of sensory input and internal dynamics to behavioral sequence generation.
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14
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Koumura T, Okanoya K. Distributed representation of discrete sequential vocalization in the Bengalese finch ( Lonchura striata var. domestica). BIOACOUSTICS 2019. [DOI: 10.1080/09524622.2019.1607558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Takuya Koumura
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Kazuo Okanoya
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
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15
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Magnúsdóttir EE, Lim R. Subarctic singers: Humpback whale (Megaptera novaeangliae) song structure and progression from an Icelandic feeding ground during winter. PLoS One 2019; 14:e0210057. [PMID: 30673737 PMCID: PMC6343865 DOI: 10.1371/journal.pone.0210057] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/05/2018] [Indexed: 12/03/2022] Open
Abstract
Humpback whale songs associated with breeding behaviors are increasingly reported outside of traditional low latitude breeding grounds. Songs from a subarctic feeding ground during the winter were quantitatively characterized to investigate the structure and temporal changes of the songs at such an atypical location. Recordings were collected from 26. January to 12. March, 2011, using bottom mounted recorders. Humpback songs were detected on 91% of the recording days with peak singing activities during 9.–26. February. The majority of the recordings included multiple chorusing singers. The songs were characterized by a) common static themes which transitioned consistently to predictable themes, b) shifting themes which occurred less predictably and c) rare themes. A set median sequence was found for four different periods (sets) of recordings (approximately 1 week each). The set medians were highly similar and formed a single cluster indicating that the sequences of themes sung in this area belonged to a single cluster of songs despite of the variation caused by the shifting themes. These subarctic winter songs could, thus, represent a characteristic song type for this area which is comparable to extensively studied songs from traditional low latitude breeding grounds. An increase in the number of themes per sequence was observed throughout the recording period including minor changes in the application of themes in the songs; indicating a gradual song progression. The results confirm that continual singing of sophisticated songs occur during the breeding season in the subarctic. In addition to being a well-established summer feeding ground the study area appears to be an important overwintering site for humpback whales delaying or canceling their migration where males engage in active sexual displays, i.e. singing. Importantly, such singing activity on a shared feeding ground likely aids the cultural transmission of songs in the North Atlantic.
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Affiliation(s)
- Edda E. Magnúsdóttir
- The University of Iceland’s Research Center in Húsavík, Húsavík, Iceland
- Department of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland
- * E-mail:
| | - Rangyn Lim
- The University of Iceland’s Research Center in Húsavík, Húsavík, Iceland
- Department of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland
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16
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Multifractal analysis reveals music-like dynamic structure in songbird rhythms. Sci Rep 2018; 8:4570. [PMID: 29545558 PMCID: PMC5854712 DOI: 10.1038/s41598-018-22933-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 03/01/2018] [Indexed: 01/01/2023] Open
Abstract
Music is thought to engage its listeners by driving feelings of surprise, tension, and relief through a dynamic mixture of predictable and unpredictable patterns, a property summarized here as “expressiveness”. Birdsong shares with music the goal to attract its listeners’ attention and might use similar strategies to achieve this. We here tested a thrush nightingale’s (Luscinia luscinia) rhythm, as represented by song amplitude envelope (containing information on note timing, duration, and intensity), for evidence of expressiveness. We used multifractal analysis, which is designed to detect in a signal dynamic fluctuations between predictable and unpredictable states on multiple timescales (e.g. notes, subphrases, songs). Results show that rhythm is strongly multifractal, indicating fluctuations between predictable and unpredictable patterns. Moreover, comparing original songs with re-synthesized songs that lack all subtle deviations from the “standard” note envelopes, we find that deviations in note intensity and duration significantly contributed to multifractality. This suggests that birdsong is more dynamic due to subtle note timing patterns, often similar to musical operations like accelerando or crescendo. While different sources of these dynamics are conceivable, this study shows that multi-timescale rhythm fluctuations can be detected in birdsong, paving the path to studying mechanisms and function behind such patterns.
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17
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de Camargo UM, Somervuo P, Ovaskainen O. PROTAX-Sound: A probabilistic framework for automated animal sound identification. PLoS One 2017; 12:e0184048. [PMID: 28863178 PMCID: PMC5581177 DOI: 10.1371/journal.pone.0184048] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Accepted: 08/17/2017] [Indexed: 11/19/2022] Open
Abstract
Autonomous audio recording is stimulating new field in bioacoustics, with a great promise for conducting cost-effective species surveys. One major current challenge is the lack of reliable classifiers capable of multi-species identification. We present PROTAX-Sound, a statistical framework to perform probabilistic classification of animal sounds. PROTAX-Sound is based on a multinomial regression model, and it can utilize as predictors any kind of sound features or classifications produced by other existing algorithms. PROTAX-Sound combines audio and image processing techniques to scan environmental audio files. It identifies regions of interest (a segment of the audio file that contains a vocalization to be classified), extracts acoustic features from them and compares with samples in a reference database. The output of PROTAX-Sound is the probabilistic classification of each vocalization, including the possibility that it represents species not present in the reference database. We demonstrate the performance of PROTAX-Sound by classifying audio from a species-rich case study of tropical birds. The best performing classifier achieved 68% classification accuracy for 200 bird species. PROTAX-Sound improves the classification power of current techniques by combining information from multiple classifiers in a manner that yields calibrated classification probabilities.
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Affiliation(s)
| | - Panu Somervuo
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Otso Ovaskainen
- Department of Biosciences, University of Helsinki, Helsinki, Finland
- Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
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18
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Sexual communication and domestication may give rise to the signal complexity necessary for the emergence of language: An indication from songbird studies. Psychon Bull Rev 2017; 24:106-110. [DOI: 10.3758/s13423-016-1165-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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19
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Sasahara K, Tchernichovski O, Takahasi M, Suzuki K, Okanoya K. A rhythm landscape approach to the developmental dynamics of birdsong. J R Soc Interface 2016; 12:rsif.2015.0802. [PMID: 26538559 PMCID: PMC4685852 DOI: 10.1098/rsif.2015.0802] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unlike simple biological rhythms, the rhythm of the oscine bird song is a learned time series of diverse sounds that change dynamically during vocal ontogeny. How to quantify rhythm development is one of the most important challenges in behavioural biology. Here, we propose a simple method, called ‘rhythm landscape’, to visualize and quantify how rhythm structure, which is measured as durational patterns of sounds and silences, emerges and changes over development. Applying this method to the development of Bengalese finch songs, we show that the rhythm structure begins with a broadband rhythm that develops into diverse rhythms largely through branching from precursors. Furthermore, an information-theoretic measure, the Jensen–Shannon divergence, was used to characterize the crystallization process of birdsong rhythm, which started with a high rate of rhythm change and progressed to a stage of slow refinement. This simple method provides a useful description of rhythm development, thereby helping to reveal key temporal constraints on complex biological rhythms.
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Affiliation(s)
- Kazutoshi Sasahara
- Department of Complex Systems Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan Laboratory for Biolinguistics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Ofer Tchernichovski
- Department of Psychology, Hunter College, City University of New York, 695 Park Avenue, New York, NY 10065, USA
| | - Miki Takahasi
- Laboratory for Biolinguistics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Kenta Suzuki
- Laboratory for Biolinguistics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan Faculty of Health Sciences, Nihon Institute of Medical Science, 1276 Shimogawara, Moroyama-machi, Iruma-gun, Saitama 350-0435, Japan
| | - Kazuo Okanoya
- Laboratory for Biolinguistics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan Department of Life Sciences, University of Tokyo, 3-8-1 Komaba, Meguro-ku, Tokyo 153-8902, Japan
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20
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Koumura T, Okanoya K. Automatic Recognition of Element Classes and Boundaries in the Birdsong with Variable Sequences. PLoS One 2016; 11:e0159188. [PMID: 27442240 PMCID: PMC4956110 DOI: 10.1371/journal.pone.0159188] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 06/28/2016] [Indexed: 11/18/2022] Open
Abstract
Researches on sequential vocalization often require analysis of vocalizations in long continuous sounds. In such studies as developmental ones or studies across generations in which days or months of vocalizations must be analyzed, methods for automatic recognition would be strongly desired. Although methods for automatic speech recognition for application purposes have been intensively studied, blindly applying them for biological purposes may not be an optimal solution. This is because, unlike human speech recognition, analysis of sequential vocalizations often requires accurate extraction of timing information. In the present study we propose automated systems suitable for recognizing birdsong, one of the most intensively investigated sequential vocalizations, focusing on the three properties of the birdsong. First, a song is a sequence of vocal elements, called notes, which can be grouped into categories. Second, temporal structure of birdsong is precisely controlled, meaning that temporal information is important in song analysis. Finally, notes are produced according to certain probabilistic rules, which may facilitate the accurate song recognition. We divided the procedure of song recognition into three sub-steps: local classification, boundary detection, and global sequencing, each of which corresponds to each of the three properties of birdsong. We compared the performances of several different ways to arrange these three steps. As results, we demonstrated a hybrid model of a deep convolutional neural network and a hidden Markov model was effective. We propose suitable arrangements of methods according to whether accurate boundary detection is needed. Also we designed the new measure to jointly evaluate the accuracy of note classification and boundary detection. Our methods should be applicable, with small modification and tuning, to the songs in other species that hold the three properties of the sequential vocalization.
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Affiliation(s)
- Takuya Koumura
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Research Fellow of Japan Society for the Promotion of Science, Tokyo, Japan
| | - Kazuo Okanoya
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Cognition and Behavior Joint Laboratory, RIKEN Brain Science Institute, Saitama, Japan
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21
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Miller P. Itinerancy between attractor states in neural systems. Curr Opin Neurobiol 2016; 40:14-22. [PMID: 27318972 DOI: 10.1016/j.conb.2016.05.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 05/20/2016] [Accepted: 05/27/2016] [Indexed: 11/25/2022]
Abstract
Converging evidence from neural, perceptual and simulated data suggests that discrete attractor states form within neural circuits through learning and development. External stimuli may bias neural activity to one attractor state or cause activity to transition between several discrete states. Evidence for such transitions, whose timing can vary across trials, is best accrued through analyses that avoid any trial-averaging of data. One such method, hidden Markov modeling, has been effective in this context, revealing state transitions in many neural circuits during many tasks. Concurrently, modeling efforts have revealed computational benefits of stimulus processing via transitions between attractor states. This review describes the current state of the field, with comments on how its perceived limitations have been addressed.
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Affiliation(s)
- Paul Miller
- Volen National Center for Complex Systems, Brandeis University, Waltham, MA 02454-9110, USA
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22
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Complexity, Predictability and Time Homogeneity of Syntax in the Songs of Cassin's Vireo (Vireo cassinii). PLoS One 2016; 11:e0150822. [PMID: 27050537 PMCID: PMC4822860 DOI: 10.1371/journal.pone.0150822] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/20/2016] [Indexed: 11/19/2022] Open
Abstract
Many species of animals deliver vocalizations in sequences presumed to be governed by internal rules, though the nature and complexity of these syntactical rules have been investigated in relatively few species. Here I present an investigation into the song syntax of fourteen male Cassin's Vireos (Vireo cassinii), a species whose song sequences are highly temporally structured. I compare their song sequences to three candidate models of varying levels of complexity-zero-order, first-order and second-order Markov models-and employ novel methods to interpolate between these three models. A variety of analyses, including sequence simulations, Fisher's exact tests, and model likelihood analyses, showed that the songs of this species are too complex to be described by a zero-order or first-order Markov model. The model that best fit the data was intermediate in complexity between a first- and second-order model, though I also present evidence that some transition probabilities are conditioned on up to three preceding phrases. In addition, sequences were shown to be predictable with more than 54% accuracy overall, and predictability was positively correlated with the rate of song delivery. An assessment of the time homogeneity of syntax showed that transition probabilities between phrase types are largely stable over time, but that there was some evidence for modest changes in syntax within and between breeding seasons, a finding that I interpret to represent changes in breeding stage and social context rather than irreversible, secular shifts in syntax over time. These findings constitute a valuable addition to our understanding of bird song syntax in free-living birds, and will contribute to future attempts to understand the evolutionary importance of bird song syntax in avian communication.
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23
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Kershenbaum A, Blumstein DT, Roch MA, Akçay Ç, Backus G, Bee MA, Bohn K, Cao Y, Carter G, Cäsar C, Coen M, DeRuiter SL, Doyle L, Edelman S, Ferrer-i-Cancho R, Freeberg TM, Garland EC, Gustison M, Harley HE, Huetz C, Hughes M, Bruno JH, Ilany A, Jin DZ, Johnson M, Ju C, Karnowski J, Lohr B, Manser MB, McCowan B, Mercado E, Narins PM, Piel A, Rice M, Salmi R, Sasahara K, Sayigh L, Shiu Y, Taylor C, Vallejo EE, Waller S, Zamora-Gutierrez V. Acoustic sequences in non-human animals: a tutorial review and prospectus. Biol Rev Camb Philos Soc 2016; 91:13-52. [PMID: 25428267 PMCID: PMC4444413 DOI: 10.1111/brv.12160] [Citation(s) in RCA: 138] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 10/02/2014] [Accepted: 10/15/2014] [Indexed: 11/30/2022]
Abstract
Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well-known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise - let alone understand - the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near-future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning, quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, 'Analysing vocal sequences in animals'. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field, across taxa and across disciplines. We also provide a tutorial-style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality.
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Affiliation(s)
- Arik Kershenbaum
- National Institute for Mathematical and Biological Synthesis, 1122 Volunteer Blvd., Suite 106, University of Tennessee, Knoxville, TN 37996-3410, USA
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
| | - Daniel T. Blumstein
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - Marie A. Roch
- Department of Computer Science, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182, USA
| | - Çağlar Akçay
- Lab of Ornithology, Cornell University, 159 Sapsucker Woods Rd, Ithaca, NY 14850, USA
| | - Gregory Backus
- Department of Biomathematics, North Carolina State University, Raleigh, NC 27607, USA
| | - Mark A. Bee
- Department of Ecology, Evolution and Behavior, University of Minnesota, 100 Ecology Building, 1987 Upper Buford Cir, Falcon Heights, MN 55108, USA
| | - Kirsten Bohn
- Integrated Science, Florida International University, Modesto Maidique Campus, 11200 SW 8th Street, AHC-4, 351, Miami, FL 33199, USA
| | - Yan Cao
- Department of Mathematical Sciences, University of Texas at Dallas, 800 W Campbell Rd, Richardson, TX 75080, USA
| | - Gerald Carter
- Biological Sciences Graduate Program, University of Maryland, College Park, MD 20742, USA
| | - Cristiane Cäsar
- Department of Psychology & Neuroscience, University of St. Andrews, St Mary’s Quad South Street, St Andrews, Fife, KY16 9JP, UK
| | - Michael Coen
- Department of Biostatistics and Medical Informatics, University of Wisconsin, K6/446 Clinical Sciences Center, 600 Highland Avenue, Madison, WI 53792-4675, USA
| | - Stacy L. DeRuiter
- School of Mathematics and Statistics, University of St. Andrews, St Andrews, KY16 9SS, UK
| | - Laurance Doyle
- Carl Sagan Center for the Study of Life in the Universe, SETI Institute, 189 Bernardo Ave, Suite 100, Mountain View, CA 94043, USA
| | - Shimon Edelman
- Department of Psychology, Cornell University, 211 Uris Hall, Ithaca, NY 14853-7601, USA
| | - Ramon Ferrer-i-Cancho
- Department of Computer Science, Universitat Politecnica de Catalunya, (Catalonia), Calle Jordi Girona, 31, 08034 Barcelona, Spain
| | - Todd M. Freeberg
- Department of Psychology, University of Tennessee, Austin Peay Building, Knoxville, Tennessee 37996, USA
| | - Ellen C. Garland
- National Marine Mammal Laboratory, AFSC/NOAA, 7600 Sand Point Way N.E., Seattle, Washington 98115, USA
| | - Morgan Gustison
- Department of Psychology, University of Michigan, 530 Church St, Ann Arbor, MI 48109, USA
| | - Heidi E. Harley
- Division of Social Sciences, New College of Florida, 5800 Bay Shore Rd, Sarasota, FL 34243, USA
| | - Chloé Huetz
- CNPS, CNRS UMR 8195, Université Paris-Sud, UMR 8195, Batiments 440-447, Rue Claude Bernard, 91405 Orsay, France
| | - Melissa Hughes
- Department of Biology, College of Charleston, 66 George St, Charleston, SC 29424, USA
| | - Julia Hyland Bruno
- Department of Psychology, Hunter College and the Graduate Center, The City University of New York, 365 Fifth Avenue, New York, NY 10016, USA
| | - Amiyaal Ilany
- National Institute for Mathematical and Biological Synthesis, 1122 Volunteer Blvd., Suite 106, University of Tennessee, Knoxville, TN 37996-3410, USA
| | - Dezhe Z. Jin
- Department of Physics, Pennsylvania State University, 104 Davey Lab, University Park, PA 16802-6300, USA
| | - Michael Johnson
- Department of Electrical and Computer Engineering, Marquette University, 1515 W. Wisconsin Ave., Milwaukee, WI 53233, USA
| | - Chenghui Ju
- Department of Biology, Queen College, The City Univ. of New York, 65-30 Kissena Blvd., Flushing, New York 11367, USA
| | - Jeremy Karnowski
- Department of Cognitive Science, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0515, USA
| | - Bernard Lohr
- Department of Biological Sciences, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - Marta B. Manser
- Institute of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Brenda McCowan
- Department of Veterinary Medicine, University of California Davis, 1 Peter J Shields Ave, Davis, CA 95616, USA
| | - Eduardo Mercado
- Department of Psychology; Evolution, Ecology, & Behavior, University at Buffalo, The State University of New York, Park Hall Room 204, Buffalo, NY 14260-4110, USA
| | - Peter M. Narins
- Department of Integrative Biology & Physiology, University of California Los Angeles, 612 Charles E. Young Drive East, Los Angeles, CA 90095-7246, USA
| | - Alex Piel
- Division of Biological Anthropology, University of Cambridge, Pembroke Street Cambridge, CB2 3QG, UK
| | - Megan Rice
- Department of Psychology, California State University San Marcos, 333 S. Twin Oaks Valley Rd., San Marcos, CA 92096-0001, USA
| | - Roberta Salmi
- Department of Anthropology, University of Georgia at Athens, 355 S Jackson St, Athens, GA 30602, USA
| | - Kazutoshi Sasahara
- Graduate School of Information Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Laela Sayigh
- Biology Department, Woods Hole Oceanographic Institution, 86 Water St, Woods Hole, MA 02543, USA
| | - Yu Shiu
- Lab of Ornithology, Cornell University, 159 Sapsucker Woods Rd, Ithaca, NY 14850, USA
| | - Charles Taylor
- Department of Ecology and Evolutionary Biology, University of California Los Angeles, 621 Charles E. Young Drive South, Los Angeles, CA 90095-1606, USA
| | - Edgar E. Vallejo
- Department of Computer Science, Monterrey Institute of Technology, Ave. Eugenio Garza Sada 2501 Sur Col. Tecnológico C.P. 64849, Monterrey, Nuevo León, Mexico
| | - Sara Waller
- Department of Philosophy, Montana State University, 2-155 Wilson Hall, Bozeman, Montana 59717, USA
| | - Veronica Zamora-Gutierrez
- Department of Zoology, University of Cambridge, Downing Street, Cambridge, CB2 3EJ, UK
- Centre for Biodiversity and Environmental Research, University College London, London WC1H 0AG, UK
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24
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Matheson AMM, Sakata JT. Relationship between the Sequencing and Timing of Vocal Motor Elements in Birdsong. PLoS One 2015; 10:e0143203. [PMID: 26650933 PMCID: PMC4674110 DOI: 10.1371/journal.pone.0143203] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Accepted: 11/02/2015] [Indexed: 11/29/2022] Open
Abstract
Accurate coordination of the sequencing and timing of motor gestures is important for the performance of complex and evolutionarily relevant behaviors. However, the degree to which motor sequencing and timing are related remains largely unknown. Birdsong is a communicative behavior that consists of discrete vocal motor elements (‘syllables’) that are sequenced and timed in a precise manner. To reveal the relationship between syllable sequencing and timing, we analyzed how variation in the probability of syllable transitions at branch points, nodes in song with variable sequencing across renditions, correlated with variation in the duration of silent gaps between syllable transitions (‘gap durations’) for adult Bengalese finch song. We observed a significant negative relationship between transition probability and gap duration: more prevalent transitions were produced with shorter gap durations. We then assessed the degree to which long-term age-dependent changes and acute context-dependent changes to syllable sequencing and timing followed this inverse relationship. Age- but not context-dependent changes to syllable sequencing and timing were inversely related. On average, gap durations at branch points decreased with age, and the magnitude of this decrease was greater for transitions that increased in prevalence than for transitions that decreased in prevalence. In contrast, there was no systematic relationship between acute context-dependent changes to syllable sequencing and timing. Gap durations at branch points decreased when birds produced female-directed courtship song compared to when they produced undirected song, and the magnitude of this decrease was not related to the direction and magnitude of changes to transition probabilities. These analyses suggest that neural mechanisms that regulate syllable sequencing could similarly control syllable timing but also highlight mechanisms that can independently regulate syllable sequencing and timing.
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Affiliation(s)
| | - Jon T. Sakata
- Department of Biology, McGill University, Montreal, Quebec, Canada
- * E-mail:
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25
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Bouchard KE, Ganguli S, Brainard MS. Role of the site of synaptic competition and the balance of learning forces for Hebbian encoding of probabilistic Markov sequences. Front Comput Neurosci 2015; 9:92. [PMID: 26257637 PMCID: PMC4508839 DOI: 10.3389/fncom.2015.00092] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 06/30/2015] [Indexed: 12/11/2022] Open
Abstract
The majority of distinct sensory and motor events occur as temporally ordered sequences with rich probabilistic structure. Sequences can be characterized by the probability of transitioning from the current state to upcoming states (forward probability), as well as the probability of having transitioned to the current state from previous states (backward probability). Despite the prevalence of probabilistic sequencing of both sensory and motor events, the Hebbian mechanisms that mold synapses to reflect the statistics of experienced probabilistic sequences are not well understood. Here, we show through analytic calculations and numerical simulations that Hebbian plasticity (correlation, covariance, and STDP) with pre-synaptic competition can develop synaptic weights equal to the conditional forward transition probabilities present in the input sequence. In contrast, post-synaptic competition can develop synaptic weights proportional to the conditional backward probabilities of the same input sequence. We demonstrate that to stably reflect the conditional probability of a neuron's inputs and outputs, local Hebbian plasticity requires balance between competitive learning forces that promote synaptic differentiation and homogenizing learning forces that promote synaptic stabilization. The balance between these forces dictates a prior over the distribution of learned synaptic weights, strongly influencing both the rate at which structure emerges and the entropy of the final distribution of synaptic weights. Together, these results demonstrate a simple correspondence between the biophysical organization of neurons, the site of synaptic competition, and the temporal flow of information encoded in synaptic weights by Hebbian plasticity while highlighting the utility of balancing learning forces to accurately encode probability distributions, and prior expectations over such probability distributions.
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Affiliation(s)
- Kristofer E Bouchard
- Life Sciences and Computational Research Divisions, Lawrence Berkeley National Laboratory Berkeley, CA, USA
| | - Surya Ganguli
- Department of Applied Physics, Stanford University Stanford, CA, USA
| | - Michael S Brainard
- Department of Physiology, University of California, San Francisco and Center for Integrative Neuroscience, University of California, San Francisco San Francisco, CA, USA ; Howard Hughes Medical Institute Chevy Chase, MD, USA
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26
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Matheson LE, Sun H, Sakata JT. Forebrain circuits underlying the social modulation of vocal communication signals. Dev Neurobiol 2015; 76:47-63. [PMID: 25959605 DOI: 10.1002/dneu.22298] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Revised: 05/01/2015] [Accepted: 05/01/2015] [Indexed: 12/27/2022]
Abstract
Across vertebrate species, signalers alter the structure of their communication signals based on the social context. For example, male Bengalese finches produce faster and more stereotyped songs when directing song to females (female-directed [FD] song) than when singing in isolation (undirected [UD] song), and such changes have been found to increase the attractiveness of a male's song. Despite the importance of such social influences, little is known about the mechanisms underlying the social modulation of communication signals. To this end, we analyzed differences in immediate early gene (EGR-1) expression when Bengalese finches produced FD or UD song. Relative to silent birds, EGR-1 expression was elevated in birds producing either FD or UD song throughout vocal control circuitry, including the interface nucleus of the nidopallium (NIf), HVC, the robust nucleus of the arcopallium (RA), Area X, and the lateral magnocellular nucleus of the anterior nidopallium (LMAN). Moreover, EGR-1 expression was higher in HVC, RA, Area X, and LMAN in males producing UD song than in males producing FD song, indicating that social context modulated EGR-1 expression in these areas. However, EGR-1 expression was not significantly different between males producing FD or UD song in NIf, the primary vocal motor input into HVC, suggesting that context-dependent changes could arise de novo in HVC. The pattern of context-dependent differences in EGR-1 expression in the Bengalese finch was highly similar to that in the zebra finch and suggests that social context affects song structure by modulating activity throughout vocal control nuclei.
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Affiliation(s)
| | - Herie Sun
- Department of Biology, McGill University
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27
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Rohrmeier M, Zuidema W, Wiggins GA, Scharff C. Principles of structure building in music, language and animal song. Philos Trans R Soc Lond B Biol Sci 2015; 370:20140097. [PMID: 25646520 PMCID: PMC4321138 DOI: 10.1098/rstb.2014.0097] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human language, music and a variety of animal vocalizations constitute ways of sonic communication that exhibit remarkable structural complexity. While the complexities of language and possible parallels in animal communication have been discussed intensively, reflections on the complexity of music and animal song, and their comparisons, are underrepresented. In some ways, music and animal songs are more comparable to each other than to language as propositional semantics cannot be used as indicator of communicative success or wellformedness, and notions of grammaticality are less easily defined. This review brings together accounts of the principles of structure building in music and animal song. It relates them to corresponding models in formal language theory, the extended Chomsky hierarchy (CH), and their probabilistic counterparts. We further discuss common misunderstandings and shortcomings concerning the CH and suggest ways to move beyond. We discuss language, music and animal song in the context of their function and motivation and further integrate problems and issues that are less commonly addressed in the context of language, including continuous event spaces, features of sound and timbre, representation of temporality and interactions of multiple parallel feature streams. We discuss these aspects in the light of recent theoretical, cognitive, neuroscientific and modelling research in the domains of music, language and animal song.
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Affiliation(s)
- Martin Rohrmeier
- Institut für Kunst- und Musikwissenschaft, Technische Universität Dresden, August-Bebel-Straße 20, 01219 Dresden, Germany
| | - Willem Zuidema
- ILLC, University of Amsterdam, PO Box 94242, 1090 CE Amsterdam, The Netherlands
| | - Geraint A Wiggins
- School of Electronic Engineering and Computer Science, Queen Mary University of London, Mile End Road, London E1 4FZ, UK
| | - Constance Scharff
- Animal Behavior, Freie Universität Berlin, Takustraße 6, 14195 Berlin, Germany
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Kershenbaum A, Bowles AE, Freeberg TM, Jin DZ, Lameira AR, Bohn K. Animal vocal sequences: not the Markov chains we thought they were. Proc Biol Sci 2014; 281:20141370. [PMID: 25143037 PMCID: PMC4150325 DOI: 10.1098/rspb.2014.1370] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/24/2014] [Indexed: 11/12/2022] Open
Abstract
Many animals produce vocal sequences that appear complex. Most researchers assume that these sequences are well characterized as Markov chains (i.e. that the probability of a particular vocal element can be calculated from the history of only a finite number of preceding elements). However, this assumption has never been explicitly tested. Furthermore, it is unclear how language could evolve in a single step from a Markovian origin, as is frequently assumed, as no intermediate forms have been found between animal communication and human language. Here, we assess whether animal taxa produce vocal sequences that are better described by Markov chains, or by non-Markovian dynamics such as the 'renewal process' (RP), characterized by a strong tendency to repeat elements. We examined vocal sequences of seven taxa: Bengalese finches Lonchura striata domestica, Carolina chickadees Poecile carolinensis, free-tailed bats Tadarida brasiliensis, rock hyraxes Procavia capensis, pilot whales Globicephala macrorhynchus, killer whales Orcinus orca and orangutans Pongo spp. The vocal systems of most of these species are more consistent with a non-Markovian RP than with the Markovian models traditionally assumed. Our data suggest that non-Markovian vocal sequences may be more common than Markov sequences, which must be taken into account when evaluating alternative hypotheses for the evolution of signalling complexity, and perhaps human language origins.
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Affiliation(s)
- Arik Kershenbaum
- National Institute for Mathematical and Biological Synthesis, Knoxville, TN, USA
| | - Ann E Bowles
- Hubbs SeaWorld Research Institute, San Diego, CA 92109, USA
| | - Todd M Freeberg
- Department of Psychology, University of Tennessee, Knoxville, TN, USA
| | - Dezhe Z Jin
- Department of Physics and the Center for Neural Engineering, Penn State University, University Park, PA, USA
| | - Adriano R Lameira
- Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Sciencepark 904, 1098 XH, Amsterdam, The Netherlands Pongo Foundation, Papenhoeflaan 91, 3421 XN, Oudewater, The Netherlands
| | - Kirsten Bohn
- Department of Biological Sciences, Florida International University, Miami, FL, USA
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James LS, Sakata JT. Vocal motor changes beyond the sensitive period for song plasticity. J Neurophysiol 2014; 112:2040-52. [PMID: 25057147 DOI: 10.1152/jn.00217.2014] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Behavior is critically shaped during sensitive periods in development. Birdsong is a learned vocal behavior that undergoes dramatic plasticity during a sensitive period of sensorimotor learning. During this period, juvenile songbirds engage in vocal practice to shape their vocalizations into relatively stereotyped songs. By the time songbirds reach adulthood, their songs are relatively stable and thought to be "crystallized." Recent studies, however, highlight the potential for adult song plasticity and suggest that adult song could naturally change over time. As such, we investigated the degree to which temporal and spectral features of song changed over time in adult Bengalese finches. We observed that the sequencing and timing of song syllables became more stereotyped over time. Increases in the stereotypy of syllable sequencing were due to the pruning of infrequently produced transitions and, to a lesser extent, increases in the prevalence of frequently produced transitions. Changes in song tempo were driven by decreases in the duration and variability of intersyllable gaps. In contrast to significant changes to temporal song features, we found little evidence that the spectral structure of adult song syllables changed over time. These data highlight differences in the degree to which temporal and spectral features of adult song change over time and support evidence for distinct mechanisms underlying the control of syllable sequencing, timing, and structure. Furthermore, the observed changes to temporal song features are consistent with a Hebbian framework of behavioral plasticity and support the notion that adult song should be considered a form of vocal practice.
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Affiliation(s)
- Logan S James
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Jon T Sakata
- Department of Biology, McGill University, Montreal, Quebec, Canada
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Katahira K, Suzuki K, Kagawa H, Okanoya K. A simple explanation for the evolution of complex song syntax in Bengalese finches. Biol Lett 2013; 9:20130842. [PMID: 24284561 DOI: 10.1098/rsbl.2013.0842] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The songs of Bengalese finches (Lonchura striata var. domestica) have complex syntax and provide an opportunity to investigate how complex sequential behaviour emerges via the evolutionary process. In this study, we suggest that a simple mechanism, i.e. many-to-one mapping from internal states onto syllables, may underlie the emergence of apparent complex syllable sequences that have higher order history dependencies. We analysed the songs of Bengalese finches and of their wild ancestor, the white-rumped munia (L. striata), whose songs are more stereotypical and simpler compared with those of Bengalese finches. The many-to-one mapping mechanism sufficiently accounted for the differences in the complexity of song syllable sequences of these two strains.
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Affiliation(s)
- Kentaro Katahira
- Center for Evolutionary Cognitive Sciences, The University of Tokyo, , 3-8-1 Komaba, Meguro-ku, Meguro, Tokyo 153-8902, Japan
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Lipkind D, Marcus GF, Bemis DK, Sasahara K, Jacoby N, Takahasi M, Suzuki K, Feher O, Ravbar P, Okanoya K, Tchernichovski O. Stepwise acquisition of vocal combinatorial capacity in songbirds and human infants. Nature 2013; 498:104-8. [PMID: 23719373 PMCID: PMC3676428 DOI: 10.1038/nature12173] [Citation(s) in RCA: 130] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Accepted: 04/08/2013] [Indexed: 11/18/2022]
Abstract
Human language, as well as birdsong, relies on the ability to arrange vocal elements in novel sequences. However, little is known about the ontogenetic origin of this capacity. We tracked the development of vocal combinatorial capacity in three species of vocal learners, combining an experimental approach in zebra finches with an analysis of natural development of vocal transitions in Bengalese finches and pre-lingual human infants and found a common, stepwise pattern of acquiring vocal transitions across species. In our first study, juvenile zebra finches were trained to perform one song and then the training target was altered, prompting the birds to swap syllable order, or insert a new syllable into a string. All birds solved these permutation tasks in a series of steps, gradually approximating the target sequence by acquiring novel pair-wise syllable transitions, sometimes too slowly to fully accomplish the task. Similarly, in the more complex songs of Bengalese finches, branching points and bidirectional transitions in song-syntax were acquired in a stepwise manner, starting from a more restrictive set of vocal transitions. The babbling of pre-lingual human infants revealed a similar developmental pattern: instead of a single developmental shift from reduplicated to variegated babbling (i.e., from repetitive to diverse sequences), we observed multiple shifts, where each novel syllable type slowly acquired a diversity of pair-wise transitions, asynchronously over development. Collectively, these results point to a common generative process that is conserved across species, suggesting that the long-noted gap between perceptual versus motor combinatorial capabilities in human infants1 may arise from the challenges in constructing new pair-wise transitions.
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Affiliation(s)
- Dina Lipkind
- Department of Psychology, Hunter College, City University of New York, New York, NY 10065, USA.
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Markowitz JE, Ivie E, Kligler L, Gardner TJ. Long-range order in canary song. PLoS Comput Biol 2013; 9:e1003052. [PMID: 23658509 PMCID: PMC3642045 DOI: 10.1371/journal.pcbi.1003052] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 03/22/2013] [Indexed: 11/18/2022] Open
Abstract
Bird songs range in form from the simple notes of a Chipping Sparrow to the rich performance of the nightingale. Non-adjacent correlations can be found in the syntax of some birdsongs, indicating that the choice of what to sing next is determined not only by the current syllable, but also by previous syllables sung. Here we examine the song of the domesticated canary, a complex singer whose song consists of syllables, grouped into phrases that are arranged in flexible sequences. Phrases are defined by a fundamental time-scale that is independent of the underlying syllable duration. We show that the ordering of phrases is governed by long-range rules: the choice of what phrase to sing next in a given context depends on the history of the song, and for some syllables, highly specific rules produce correlations in song over timescales of up to ten seconds. The neural basis of these long-range correlations may provide insight into how complex behaviors are assembled from more elementary, stereotyped modules. Bird songs range in form from the simple notes of a Chipping Sparrow to the complex repertoire of the nightingale. Recent studies suggest that bird songs may contain non-adjacent dependencies where the choice of what to sing next depends on the history of what has already been produced. However, the complexity of these rules has not been examined statistically for the most elaborate avian singers. Here we show that one complex singer—the domesticated canary—produces a song that is strongly influenced by long-range rules. The choice of how long to repeat a given note or which note to choose next depends on the history of the song, and these dependencies span intervals of time much longer than previously assumed for birdsong. Like most forms of human music, the songs of canaries contain patterns expressed over long timescales, governed by rules that apply to multiple levels of a temporal hierarchy. This vocal complexity provides a valuable model to examine how ordered behaviors are assembled from more elementary neural components in a relatively simple neural circuit.
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Affiliation(s)
- Jeffrey E. Markowitz
- Department of Cognitive and Neural Systems, Boston University, Boston, Massachusetts, United States of America
- Center of Excellence for Learning in Education, Science and Technology, Boston, Massachusetts, United States of America
| | - Elizabeth Ivie
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
| | - Laura Kligler
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
| | - Timothy J. Gardner
- Center of Excellence for Learning in Education, Science and Technology, Boston, Massachusetts, United States of America
- Department of Biology, Boston University, Boston, Massachusetts, United States of America
- * E-mail:
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Abstract
Variation in sequencing of actions occurs in many natural behaviors, yet how such variation is maintained is poorly understood. We investigated maintenance of sequence variation in adult Bengalese finch song, a learned skill with rendition-to-rendition variation in the sequencing of discrete syllables (i.e., syllable "b" might transition to "c" with 70% probability and to "d" with 30% probability). We found that probabilities of transitions ordinarily remain stable but could be modified by delivering aversive noise bursts following one transition (e.g., "b→c") but not the alternative (e.g., "b→d"). Such differential reinforcement induced gradual, adaptive decreases in probabilities of targeted transitions and compensatory increases in alternative transitions. Thus, the normal stability of transition probabilities does not reflect hardwired premotor circuitry. While all variable transitions could be modified by differential reinforcement, some were less readily modified than others; these were cases that exhibited more alternation between possible transitions than predicted by chance (i.e., "b→d " would tend to follow "b→c " and vice versa). These history-dependent transitions were less modifiable than more stochastic transitions. Similarly, highly stereotyped transitions (which are completely predictable) were not modifiable. This suggests that stochastically generated variability is crucial for sequence modification. Finally, we found that, when reinforcement ceased, birds gradually restored transition probabilities to their baseline values. Hence, the nervous system retains a representation of baseline probabilities and has the impetus to restore them. Together, our results indicate that variable sequencing in a motor skill can reflect an end point of learning that is stably maintained via continual self-monitoring.
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ten Cate C, Okanoya K. Revisiting the syntactic abilities of non-human animals: natural vocalizations and artificial grammar learning. Philos Trans R Soc Lond B Biol Sci 2012; 367:1984-94. [PMID: 22688634 DOI: 10.1098/rstb.2012.0055] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The domain of syntax is seen as the core of the language faculty and as the most critical difference between animal vocalizations and language. We review evidence from spontaneously produced vocalizations as well as from perceptual experiments using artificial grammars to analyse animal syntactic abilities, i.e. abilities to produce and perceive patterns following abstract rules. Animal vocalizations consist of vocal units (elements) that are combined in a species-specific way to create higher order strings that in turn can be produced in different patterns. While these patterns differ between species, they have in common that they are no more complex than a probabilistic finite-state grammar. Experiments on the perception of artificial grammars confirm that animals can generalize and categorize vocal strings based on phonetic features. They also demonstrate that animals can learn about the co-occurrence of elements or learn simple 'rules' like attending to reduplications of units. However, these experiments do not provide strong evidence for an ability to detect abstract rules or rules beyond finite-state grammars. Nevertheless, considering the rather limited number of experiments and the difficulty to design experiments that unequivocally demonstrate more complex rule learning, the question of what animals are able to do remains open.
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Affiliation(s)
- Carel ten Cate
- Behavioural Biology, Institute of Biology and Leiden Institute for Brain and Cognition, Leiden University, PO Box 9505, 2300 RA Leiden, The Netherlands.
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Berwick RC, Beckers GJL, Okanoya K, Bolhuis JJ. A Bird's Eye View of Human Language Evolution. FRONTIERS IN EVOLUTIONARY NEUROSCIENCE 2012; 4:5. [PMID: 22518103 PMCID: PMC3325485 DOI: 10.3389/fnevo.2012.00005] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Accepted: 03/20/2012] [Indexed: 12/29/2022]
Abstract
COMPARATIVE STUDIES OF LINGUISTIC FACULTIES IN ANIMALS POSE AN EVOLUTIONARY PARADOX: language involves certain perceptual and motor abilities, but it is not clear that this serves as more than an input-output channel for the externalization of language proper. Strikingly, the capability for auditory-vocal learning is not shared with our closest relatives, the apes, but is present in such remotely related groups as songbirds and marine mammals. There is increasing evidence for behavioral, neural, and genetic similarities between speech acquisition and birdsong learning. At the same time, researchers have applied formal linguistic analysis to the vocalizations of both primates and songbirds. What have all these studies taught us about the evolution of language? Is the comparative study of an apparently species-specific trait like language feasible? We argue that comparative analysis remains an important method for the evolutionary reconstruction and causal analysis of the mechanisms underlying language. On the one hand, common descent has been important in the evolution of the brain, such that avian and mammalian brains may be largely homologous, particularly in the case of brain regions involved in auditory perception, vocalization, and auditory memory. On the other hand, there has been convergent evolution of the capacity for auditory-vocal learning, and possibly for structuring of external vocalizations, such that apes lack the abilities that are shared between songbirds and humans. However, significant limitations to this comparative analysis remain. While all birdsong may be classified in terms of a particularly simple kind of concatenation system, the regular languages, there is no compelling evidence to date that birdsong matches the characteristic syntactic complexity of human language, arising from the composition of smaller forms like words and phrases into larger ones.
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Affiliation(s)
- Robert C. Berwick
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of TechnologyCambridge, MA, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of TechnologyCambridge, MA, USA
| | - Gabriël J. L. Beckers
- Department of Behavioural Neurobiology, Max Planck Institute for OrnithologySeewiesen, Germany
| | - Kazuo Okanoya
- Department of Cognitive and Behavioral Sciences, The University of TokyoTokyo, Japan
| | - Johan J. Bolhuis
- Behavioural Biology, Helmholtz Institute, University of UtrechtUtrecht, The Netherlands
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