Animal vocal sequences: not the Markov chains we thought they were

Kershenbaum, Arik; Bowles, Ann E.; Freeberg, Todd M.; Jin, Dezhe Z.; Lameira, Adriano R.; Bohn, Kirsten M.

doi:10.1098/rspb.2014.1370

Cited by 98 publications

(112 citation statements)

References 60 publications

(95 reference statements)

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“…Here we confirm that classical metrics like mean or coefficient of variation are not always sufficient 608 for the study of animal vocal interaction sequences (Kershenbaum et al, 2014). We show that shortterm memory model like Markov can explain vocal exchanges dynamics in a particular context (no 610 visual contact), but long-term memory dynamics should be studied in various contexts in the future.…”

supporting

confidence: 53%

Impact of visual contact on vocal interaction dynamics of pair-bonded birds

et al. 2015

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Animal social interactions usually revolve around several sensory modalities. For birds, these are 25 primarily visual and acoustic. However, some habitat specificities or large distances may 26 temporarily hinder or limit visual information transmission making acoustic transmission a central 27 channel of communication even during complex social behaviours. Here we show the impact of 28 visual limitation on the vocal dynamics between zebra finches partners. Pairs were acoustically 29 recorded during a separation and reunion protocol with gradually decreasing distance without visual 30 contact. Without visual contact, pairs display more correlated vocal exchanges than with visual 31 contact. We also analysed the turn-taking sequences of individuals' vocalisations during an 32 exchange with or without visual contact. We show that in the absence of visual contact, the identity 33 of a vocalising individual is well predicted by the knowledge of the identity of the previous 34vocaliser. This property is characteristic of a stochastic process called a Markov chain and we show 35here that deprived of visual contact, turn-taking sequences are Markovian. Thus, both the temporal 36 correlation between the calls of the two partners and Markov properties of acoustic interactions 37 indicate that in the absence of visual clues the decision to emit a call is taken on a very short-term 38 basis and solely on acoustic information (both temporal and identity of caller). Strikingly, when 39 individuals are in visual contact both these features of their acoustic social interactions disappear 40 indicating that birds adapt their calling dynamics to cope with limited visual cues. 41 42 Keywords: Markov chains, pair-bond, turn-taking, visual contact, vocal communication, zebra finch 43Whilst individual traits usually drive the probability of survival and breeding in a given 44 environment, properties emerging from interactions between mates can also influence the success of 45 a pair, overriding the influence of intrinsic individual quality (Ens, Safriel, & Harris, 1993; Ryan & 46 Altmann, 2001). Many long-term monogamous species of birds show an increase in breeding 47 success with pair bond duration, which is attributed to the improvement in partners' coordination 48 over time (mate familiarity effect, Black, 2001;Black & Hulme, 1996;Forslund & Pärt, 1995). The 49 strength of coordination and synchronization of behaviours within a pair may at least partly depend 50 on the quality of communication between the individuals. 51 52In birds, vocalizations exchanges lay at the heart of pair bond formation and courtship (Marler & 53 Slabbekoorn, 2004; Tobias, Gamarra-Toledo, Garcia-Olaechea, Pulgarin, & Seddon, 2011), but 54 vocal interactions may also function in partner's recognition (Beer, 1971;Marzluff, 1988; 55 Robertson, 1996; Vignal, Mathevon, & Mottin, 2008), pair bond maintenance (Beletsky & Orians, 56 1985), foraging behaviour (Evans & Marler, 1994;Gyger & Marler, 1988), vigilance against 57 predators (Colombelli-Neg...

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confidence: 53%

Impact of visual contact on vocal interaction dynamics of pair-bonded birds

et al. 2015

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“…The finding that gelada vocal sequences show the same negative relationship between the size of the whole construct and the size of its constituents, as is found in human language, suggests that equivalent principles of self-organization (24) underpin the vocal communication of our own species and another primate. Although there are elementary differences between the vocal faculties of humans and of other animals (38-40), exploring and comparing mathematical, structural properties of their communication systems can be informative (26,41). As language is inherently sequence-based and animals of many taxa, from bacteria (42) to great apes (43), combine individual signals into sequences, identifying basic patterns of sequence structure that are shared by human and nonhuman animal communication provides evidence for evolutionary preservation, or convergent evolution, of the processes underlying the emergence of such patterns (41).…”

Section: Discussionmentioning

confidence: 99%

“…Although there are elementary differences between the vocal faculties of humans and of other animals (38-40), exploring and comparing mathematical, structural properties of their communication systems can be informative (26,41). As language is inherently sequence-based and animals of many taxa, from bacteria (42) to great apes (43), combine individual signals into sequences, identifying basic patterns of sequence structure that are shared by human and nonhuman animal communication provides evidence for evolutionary preservation, or convergent evolution, of the processes underlying the emergence of such patterns (41). Importantly, adherence to Menzerath's law need not involve any cognitively demanding planning by the animals producing sequences of sound.…”

Section: Discussionmentioning

confidence: 99%

Gelada vocal sequences follow Menzerath’s linguistic law

Gustison

Semple

Ferrer-i-Cancho

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

140

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Identifying universal principles underpinning diverse natural systems is a key goal of the life sciences. A powerful approach in addressing this goal has been to test whether patterns consistent with linguistic laws are found in nonhuman animals. Menzerath's law is a linguistic law that states that, the larger the construct, the smaller the size of its constituents. Here, to our knowledge, we present the first evidence that Menzerath's law holds in the vocal communication of a nonhuman species. We show that, in vocal sequences of wild male geladas (Theropithecus gelada), construct size (sequence size in number of calls) is negatively correlated with constituent size (duration of calls). Call duration does not vary significantly with position in the sequence, but call sequence composition does change with sequence size and most call types are abbreviated in larger sequences. We also find that intercall intervals follow the same relationship with sequence size as do calls. Finally, we provide formal mathematical support for the idea that Menzerath's law reflects compression-the principle of minimizing the expected length of a code. Our findings suggest that a common principle underpins human and gelada vocal communication, highlighting the value of exploring the applicability of linguistic laws in vocal systems outside the realm of language.communication | language | primate | Menzerath | Zipf

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“…As we will see, the morphology mostly involves simple calls, but in at least one case (Campbell's -oo) we find a root-suffix structure, possibly with a compositional semantics. The syntax is in all clear cases simple and finitestate, and our findings will be extremely modest in this area (see Kershenbaum et al 2014aKershenbaum et al , 2014b for a far more ambitious program in animal syntax). With respect to meaning, nearly all cases of call concatenation can be analyzed without positing any non-trivial semantic operation -each call can be analyzed as a separate utterance.…”

Section: Introductionmentioning

confidence: 99%

Formal monkey linguistics

Schlenker¹,

Chemla

Schel

et al. 2016

Theoretical Linguistics

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We argue that rich data gathered in experimental primatology in the last 40 years can benefit from analytical methods used in contemporary linguistics. Focusing on the syntactic and especially semantic side, we suggest that these (iii) how are the meanings of individual calls combined? (iv) how do calls or call sequences compete with each other when several are appropriate in a given situation? (v) how did the form and meaning of calls evolve? We address these questions in five case studies pertaining to cercopithecines (Putty-nosed monkeys, Blue monkeys, and Campbell's monkeys), colobinae (Guereza monkeys and King Colobus monkeys), and New World monkeys (Titi monkeys). The morphology mostly involves simple calls, but in at least one case (Campbell's -oo) we find a root-suffix structure, possibly with a compositional semantics. The syntax is in all clear cases simple and finite-state. With respect to meaning, nearly all cases of call concatenation can be analyzed as conjunction. But a key question concerns the division of labor between semantics, pragmatics and the environmental context ('world' knowledge and context change). An apparent case of dialectal variation in the semantics (Campbell's krak) can arguably be analyzed away if one posits sufficiently powerful mechanisms of competition among calls, akin to scalar implicatures. An apparent case of non-compositionality (Putty-nosed pyow-hack sequences) can be analyzed away if one further posits a pragmatic principle of 'urgency', whereby threat-related calls must come early in sequences (another potential case of non-compositionality -Colobus snort-roar sequences -might justify assigning non-compositional meanings to complex calls, but results are tentative). Finally, rich Titi sequences in which two calls are re-arranged in complex ways so as to reflect information about both predator identity and location are argued not to involve a complex syntax/semantics interface, but rather a finegrained interaction between simple call meanings and the environmental context. With respect to call evolution, we suggest that the remarkable preservation of call form and function over millions of years should make it possible to lay the groundwork for an evolutionary monkey linguistics, which we illustrate with cercopithecine booms, and with a comparative analysis of Blue monkey and Putty-nosed monkey repertoires. Throughout, we aim to compare possible theories rather than to fully adjudicate between them, and our claims are correspondingly modest. But we hope that our methods could lay the groundwork for a formal monkey linguistics combining data from primatology with formal techniques from linguistics (from which it does not follow that the calls under study share non-trivial properties, let alone an evolutionary history, with human language).

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Animal vocal sequences: not the Markov chains we thought they were

Cited by 98 publications

References 60 publications

Impact of visual contact on vocal interaction dynamics of pair-bonded birds

Impact of visual contact on vocal interaction dynamics of pair-bonded birds

Gelada vocal sequences follow Menzerath’s linguistic law

Formal monkey linguistics

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