Human Vocal Communication Research Articles

Degrees of Separation: Are mirror neurons human language specific?

Event Abstract Back to Event Degrees of Separation: Are mirror neurons human language specific? Bernadine Cocks1, 2*, Graham Jamieson1, Ian Evans1 and Bruce Stevenson1 1 University of New England, Behavioural, Cognitive and Social Sciences (BCSS) - Psychology, Australia 2 University of South Australia, Division Office, Australia Since the discovery of mirror neurons in the late 1990s, a number of theories have been proposed concerning their role in human cognition, most notably in the area of human language. Although a handful of studies have examined such theories, none thus far have tested for differences in mirror neuron responses in the human brain between listening to human and non-human vocal communication. To this end, continuous EEG was recorded as human participants in the current study listened to a random selection of animal vocalizations including song bird tunes and monkey and ape calls, as well as a selection of everyday English language words. Event related band power decomposition is used to investigate differences in alpha desynchronization in known mirror neuron regions between listening to human and non-human communications. If mirror neurons respond selectively to human language, there should be no evidence of mirror neuron activity (event related alpha desynchronization) in relation to non-human vocalizations; if, however, mirror neurons do respond to non-human vocal communications, it is predicted that this response will be scale with phylogenetic distance from humans. Keywords: Mirror Neurons, Language, non-human vocalizations, EEG, event related alpha desynchronization Conference: ACNS-2012 Australasian Cognitive Neuroscience Conference, Brisbane, Australia, 29 Nov - 2 Dec, 2012. Presentation Type: Oral Presentation Topic: Language Citation: Cocks B, Jamieson G, Evans I and Stevenson B (2012). Degrees of Separation: Are mirror neurons human language specific?. Conference Abstract: ACNS-2012 Australasian Cognitive Neuroscience Conference. doi: 10.3389/conf.fnhum.2012.208.00026 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 Oct 2012; Published Online: 07 Nov 2012. * Correspondence: Mrs. Bernadine Cocks, University of New England, Behavioural, Cognitive and Social Sciences (BCSS) - Psychology, Armidale, NSW, 2350, Australia, Bernie.Cocks@unisa.edu.au Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Bernadine Cocks Graham Jamieson Ian Evans Bruce Stevenson Google Bernadine Cocks Graham Jamieson Ian Evans Bruce Stevenson Google Scholar Bernadine Cocks Graham Jamieson Ian Evans Bruce Stevenson PubMed Bernadine Cocks Graham Jamieson Ian Evans Bruce Stevenson Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Vocal Tract Articulation in Zebra Finches

BackgroundBirdsong and human vocal communication are both complex behaviours which show striking similarities mainly thought to be present in the area of development and learning. Recent studies, however, suggest that there are also parallels in vocal production mechanisms. While it has been long thought that vocal tract filtering, as it occurs in human speech, only plays a minor role in birdsong there is an increasing number of studies indicating the presence of sound filtering mechanisms in bird vocalizations as well.Methodology/Principal FindingsCorrelating high-speed X-ray cinematographic imaging of singing zebra finches (Taeniopygia guttata) to song structures we identified beak gape and the expansion of the oropharyngeal-esophageal cavity (OEC) as potential articulators. We subsequently manipulated both structures in an experiment in which we played sound through the vocal tract of dead birds. Comparing acoustic input with acoustic output showed that OEC expansion causes an energy shift towards lower frequencies and an amplitude increase whereas a wide beak gape emphasizes frequencies around 5 kilohertz and above.ConclusionThese findings confirm that birds can modulate their song by using vocal tract filtering and demonstrate how OEC and beak gape contribute to this modulation.

Brevity is not always a virtue in primate communication.

Semple et al. (Semple et al. in press, Biol. Lett. (doi:10.1098/rsbl.2009.1062)) argued that the 'law of brevity' (an inverse relationship between word length and frequency of use) applies not only to human language but also to vocal signalling in non-human primates, because coding efficiency is paramount in both situations. We analysed the frequency of use of signals of different duration in the vocal repertoires of two Neotropical primate species studied in the wild-the common marmoset (Callithrix jacchus) and the golden-backed uakari (Cacajao melanocephalus). The key prediction of the law of brevity was not supported in either species: although the most frequently emitted calls were relatively brief, they were not the shortest signals in the repertoire. The costs and benefits associated with signals of different duration must be appreciated to understand properly their frequency of use. Although relatively brief vocal signals may be favoured by natural selection in order to minimize energetic costs, the very briefest signals may be ambiguous, contain reduced information or be difficult to detect or locate, and may therefore be selected against. Analogies between human language and vocal communication in animals can be misleading as a basis for understanding frequency of use, because coding efficiency is not the only factor of importance in animal communication, and the costs and benefits associated with different signal durations will vary in a species-specific manner.

Mechanisms of song perception in oscine birds

Songbirds share a number of parallels with humans that make them an attractive model system for studying the behavioral and neurobiological mechanisms that underlie the learning and processing of vocal communication signals. Here we review the perceptual and cognitive mechanisms of audition in birds, and emphasize the behavioral and neural basis of song recognition. Where appropriate, we point out a number of intersections with human vocal communication behavior that suggest common mechanisms amenable to further study, and limitations of birdsong as a model for human language.

Efficiency of coding in macaque vocal communication

A key characteristic of human language efficiency is that more frequently used words tend to be shorter in length-the 'law of brevity'. To date, no test of this relationship between frequency of use and length has been carried out on non-human animal vocal communication. We show here that the vocal repertoire of the Formosan macaque (Macaca cyclopis) conforms to the pattern predicted by the law of brevity, with an inverse relationship found between call duration and rate of utterance. This finding provides evidence for coding efficiency in the vocal communication system of this species, and indicates commonality in the basic structure of the coding system between human language and vocal communication in this non-human primate.

Language out of Music: The Four Dimensions of Vocal Learning

A growing consensus drawing on research in a wide variety of disciplines has, over the last fifteen years or so, argued the need to revisit Darwin's conjecture of 1871 that language may be descended from an existing, musical medium of communication that developed from animal calls. This paper seeks to examine, in an extension of Hockett's analysis of the design features required for linguistic communication, the nature of the acoustic information produced and perceived in human vocalisation, and to consider the anatomical and neural mechanisms on which these depend. An attempt is made to sketch an evolutionary chronology for key prerequisites of human orality. Cross‐species comparisons are employed to illuminate the role of four acoustic variables (pitch, duration, amplitude and timbre), viewing the potential for human vocal productivity from the perspective of animal communication. Although humans are the only species to combine entrainment to pulse with attunement to precisely‐tracked pitches, we also depend both for musical interaction and the production and perception of vowel sounds on precise and conscious control of the property of timbre. Drawing on, amongst others, Scherer's analyses of emotionally triggered sounds in a variety of species, and Fernald's presentation of the similarities of infant cries and adult production of infant‐directed speech in a variety of cultures and languages, a case is made for the instinctive components of human communication being more music‐like than language‐like. In conclusion, historical and comparative data are employed to outline the adaptive and exaptive sequence by which human vocal communication evolved. The roles of selective pressures that conform to different adaptive models are compared—natural selection, sexual selection, group selection—leading to the proposal that all of these must have played their part at different stages in the process in a ‘mosaic’ model consistent with the development of other human traits.

Vocal-Tract Resonances as Indexical Cues in Rhesus Monkeys

SummaryVocal-tract resonances (or formants) are acoustic signatures in the voice and are related to the shape and length of the vocal tract. Formants play an important role in human communication, helping us not only to distinguish several different speech sounds [1], but also to extract important information related to the physical characteristics of the speaker, so-called indexical cues. How did formants come to play such an important role in human vocal communication? One hypothesis suggests that the ancestral role of formant perception—a role that might be present in extant nonhuman primates—was to provide indexical cues [2–5]. Although formants are present in the acoustic structure of vowel-like calls of monkeys [3–8] and implicated in the discrimination of call types [8–10], it is not known whether they use this feature to extract indexical cues. Here, we investigate whether rhesus monkeys can use the formant structure in their “coo” calls to assess the age-related body size of conspecifics. Using a preferential-looking paradigm [11, 12] and synthetic coo calls in which formant structure simulated an adult/large- or juvenile/small-sounding individual, we demonstrate that untrained monkeys attend to formant cues and link large-sounding coos to large faces and small-sounding coos to small faces—in essence, they can, like humans [13], use formants as indicators of age-related body size.

Development and Evolution in Human Vocal Communication

Development and Evolution in Human Vocal Communication

Continuities in vocal communication argue against a gestural origin of language

To conclude that language evolved from vocalizations, through gestures, then back to vocalizations again, one must first reject the simpler hypothesis that language evolved from prelinguistic vocalizations. There is no reason to do so. Many studies – not cited by Arbib – document continuities in behavior, perception, cognition, and neurophysiology between human speech and primate vocal communication.

The neonate cry after cesarean section and vaginal delivery during the first minutes of life

Although the option for vaginal delivery is most physiological, the achievement of cesarean section is very common in Brazil. The neonate cry represents the beginning of both processes, physiological adaptation and human vocal communication. The cry emission depends on the functioning of respiratory and laryngeal muscles, which are controlled by the nervous system. The acoustic analysis of neonate cry is useful in the assessment of healthy babies and can be used to characterize the signals of diseases through a previously multidisciplinary diagnosis, with immediate medical intervention. The present study compared the acoustic cry characteristics of 30 healthy newborn after a cesarean section and 30 healthy newborn after a vaginal delivery, of both genders, from the exact moment of birth until the first 5 min of life. Using the softwares VOXMETRIA and GRAM, it was possible to analyze the duration, frequency, intensity, occurrence, localization and inspiratory phonation, besides the type of spectrographic tracings. The acoustic cry characteristics of newborns after a C section and a vaginal delivery could evidence not only harmonic, expiratory, acute and strong emissions, but also emissions rich in sounds and varied in types of melody. The differences found can be related to the physiology of birth.

Perception and judgement of whispered vocalisations

Whispering is regarded as a close-contact vocalisation which, in structural terms, clearly differs from normal (phonated) speech. Here, we present the first experimental evidence for specific functional differences that additionally exist between these two forms of human vocal communication. Such evidence was collected by an inquiry into the perception and also the social judgement of whispered vocalisations. Subjects were young adults (mainly students; N=202) who were exposed to auditory stimuli which, for exclusion of verbal effects, were given in artificial vocal patterns only. To test for possible social effects, our stimuli (whispered phrases or, for control, phonated phrases) simulated exposures to three socially different situations: 'monologues', 'dialogues', and 'dialogues including laughter'. Evaluation of self-report data collected after each stimulation revealed that only the whispered stimuli received significant numbers of socially negative judgements or votes, that documented 'feelings of social segregation'. Such judgements were most frequent after exposures to 'dialogues including laughter', but less frequent after 'monologues'. Taken together our study suggests that whispering is not just a mere close-contact vocalisation, but a vocal expression with specific social side-effects. To explain these effects we presume that whispering signals primarily a strong affiliation of its users, and that such role may make other listeners feel to be excluded from a whispered interaction.

The acoustic features of human laughter

Remarkably little is known about the acoustic features of laughter, despite laughter’s ubiquitous role in human vocal communication. Outcomes are described for 1024 naturally produced laugh bouts recorded from 97 young adults. Acoustic analysis focused on temporal characteristics, production modes, source- and filter-related effects, and indexical cues to laugher sex and individual identity. The results indicate that laughter is a remarkably complex vocal signal, with evident diversity in both production modes and fundamental frequency characteristics. Also of interest was finding a consistent lack of articulation effects in supralaryngeal filtering. Outcomes are compared to previously advanced hypotheses and conjectures about this species-typical vocal signal.

The frame/content theory of evolution of speech production.

The species-specific organizational property of speech is a continual mouth open-close alternation, the two phases of which are subject to continual articulatory modulation. The cycle constitutes the syllable, and the open and closed phases are segments-vowels and consonants, respectively. The fact that segmental serial ordering errors in normal adults obey syllable structure constraints suggests that syllabic "frames" and segmental "content" elements are separately controlled in the speech production process. The frames may derive from cycles of mandibular oscillation present in humans from babbling onset, which are responsible for the open-close alternation. These communication-related frames perhaps first evolved when the ingestion-related cyclicities of mandibular oscillation (associated with mastication [chewing] sucking and licking) took on communicative significance as lipsmacks, tonguesmacks, and teeth chatters--displays that are prominent in many nonhuman primates. The new role of Broca's area and its surround in human vocal communication may have derived from its evolutionary history as the main cortical center for the control of ingestive processes. The frame and content components of speech may have subsequently evolved separate realizations within two general purpose primate motor control systems: (1) a motivation-related medial "intrinsic" system, including anterior cingulate cortex and the supplementary motor area, for self-generated behavior, formerly responsible for ancestral vocalization control and now also responsible for frames, and (2) a lateral "extrinsic" system, including Broca's area and surround, and Wernicke's area, specialized for response to external input (and therefore the emergent vocal learning capacity) and more responsible for content.