Communication In Nonhuman Primates Research Articles

Who’s afraid of the vowel shift rule?

The historical Great Vowel Shift, and its putative Present-Day English successor, the Vowel Shift Rule, represent everything that is problematic for Optimality Theory. Optimality Theorists have exercised considerable ingenuity in attempting to model these processes; but their analyses involve either the abandonment of ‘classical’ tenets of OT, such as constraint innateness and universality; or the introduction of new constraint types and theoretical machinery; or indeed both. I shall argue that, rather than formulating increasingly baroque machinery to deal with alternations of this kind, it would be preferable to accept that OT is suited to certain phonological phenomena but not others. Rather than seeing this as an inherent weakness in the model, we can perceive it as a strength, if we accept an essential distinction between prosody, the heartland of OT, and melody. External and independent evidence for the prosody-melody distinction comes from areas as diverse as language impairment, brain lateralisation, and the vocal communication of non-human primates; together, these point to an evolutionary disparity in the development of prosodic and segmental phonology, such that the former is suited to analysis via innate and universal constraints, while the latter is not.

Using PET H 2O 15 brain imaging to study the functional–anatomical correlates of non-human primate communication

In this article, we describe methods for using oxygen-15 water (H 2O 15) positron emission tomography (PET) to explore the functional neuroanatomy of cognition in awake, non-human primates. The discussion is based on a recent study designed to identify regions in the monkey brain associated with perceiving auditory stimuli, and species-specific calls, in particular [Gil-da-Costa et al., Proc. Natl. Acad. Sci. USA 101 (2004) 17516–17521]. Details are provided concerning critical aspects of the experimental paradigm, including pre-scanning habituation sessions to acclimate the animals to the PET scanner environment, and details of a pilot study to determine the auditory stimulus parameters necessary to produce robust activity in brain regions known to process auditory information (belt and parabelt regions of monkey auditory cortex). Methods for acquiring and analyzing PET data to identify significant regions of brain activity in single animals are also presented.

Gestures in human and nonhuman primates

The present article offers a condensed overview, of why a comparative view on gestures in human and nonhuman primates may offer important insights to both: researchers of human as well as of nonhuman primates. It is argued that a comparative view may further contribute to the debate over the evolution of language but that in addition it may also enhance understanding of the relation of language and gesture in humans. The article sketches programmatic issues, which are summarized in the list of framing questions for the workshop and this special issue on “Gestural communication in nonhuman and human primates”; it is aimed to clarify conceptual and methodological prerequisites and to offer points of departure for future comparative research.

Gestural communication of apes

Gestural communication of nonhuman primates may allow insight into the evolutionary scenario of human communication given the flexible use and learning of gestures as opposed to vocalizations. This paper provides an overview of the work on the gestural communication of apes with the focus on their repertoire, learning mechanisms, and the flexibility of gesture use during interactions with conspecifics. Although there is a variation between the species in the types and numbers of gestures performed, the influence of ecology, social structure and cognitive skills on their gestural repertoires is relatively restricted. As opposed to humans, apes do not use their gestures referentially nor do their gestures show the symbolic or conventionalized features of human gestural communication. However, since the gestural repertoires of apes are characterized by a high degree of individual variability and flexibility of use as opposed to their vocalizations it seems plausible that the gestures were the modality within which symbolic communication first evolved.

Gestural Communication in Nonhuman and Human Primates. Workshop held at the Max Planck Institute for Evolutionary Anthropology, Leipzig, March 28th–30th, 2004.

Gestural Communication in Nonhuman and Human Primates. Workshop held at the Max Planck Institute for Evolutionary Anthropology, Leipzig, March 28th–30th, 2004.

Influence of Social Context on the Use of Blended and Graded Facial Displays in Chimpanzees

Our understanding of social communication and emotional behavior in nonhuman primates has advanced considerably through research over the past half century. Chimpanzee facial displays have typically been described as highly graded communicative signals, but we propose an additional distinction: blended displays. They appear to be morphologically and acoustically similar to the expressions in ≥2 prototypical/parent categories. We describe the facial and vocal communicative repertoire of chimpanzees and examine how they use graded and blended signals in different social contexts. Data from behavioral observations revealed that they used facial displays differently depending on the social context. Specifically, the variability can be explained by 7 factors representing nervousness and distress, agonism, contact reassurance, excitement, greetings, play, and vigilance. Additionally, the use of blended displays was not simply divided between the contexts that elicited the parent types, nor were they used in totally unique contexts. Instead, the data showed that the contextual use of blended displays is primarily correlated with the social contexts that elicited only one of the parent expressions. Thus, the blended displays appeared to reflect conflicting internal motivational states in the sender, instead of expressing features of the external environment. We proffer several possible explanations for how the blended signals may be interpreted by receivers and why they would be contextually associated with only one parent group.

Constraints and preadaptations in the earliest stages of language evolution

If we accept the view that language first evolved from the conceptual structure of our pre-linguistic ancestors, several questions arise, including: What kind of structure? Concepts about what? Here we review research on the vocal communication and cognition of nonhuman primates, focusing on results that may be relevant to the earliest stages of language evolution. From these data we conclude, first, that nonhuman primates' inability to represent the mental states of others makes their communication fundamentally different from human language. Second, while nonhuman primates' production of vocalizations is highly constrained, their ability to extract complex information from sounds is not. Upon hearing vocalizations, listeners acquire information about their social companions that is referential, discretely coded, hierarchically structured, rule-governed, and propositional. We therefore suggest that, in the earliest stages of language evolution, communication had a formal structure that grew out of its speakers' knowledge of social relations.

Introduction: Gestural communication in nonhuman and human primates

Introduction: Gestural communication in nonhuman and human primates

Gestures in human and nonhuman primates: Why we need a comparative view

The present article offers a condensed overview, of why a comparative view on gestures in human and nonhuman primates may offer important insights to both: researchers of human as well as of nonhuman primates. It is argued that a comparative view may further contribute to the debate over the evolution of language but that in addition it may also enhance understanding of the relation of language and gesture in humans. The article sketches programmatic issues, which are summarized in the list of framing questions for the workshop and this special issue on “Gestural communication in nonhuman and human primates”; it is aimed to clarify conceptual and methodological prerequisites and to offer points of departure for future comparative research.

Gestural communication of apes

Gestural communication of nonhuman primates may allow insight into the evolutionary scenario of human communication given the flexible use and learning of gestures as opposed to vocalizations. This paper provides an overview of the work on the gestural communication of apes with the focus on their repertoire, learning mechanisms, and the flexibility of gesture use during interactions with conspecifics. Although there is a variation between the species in the types and numbers of gestures performed, the influence of ecology, social structure and cognitive skills on their gestural repertoires is relatively restricted. As opposed to humans, apes do not use their gestures referentially nor do their gestures show the symbolic or conventionalized features of human gestural communication. However, since the gestural repertoires of apes are characterized by a high degree of individual variability and flexibility of use as opposed to their vocalizations it seems plausible that the gestures were the modality within which symbolic communication first evolved.

Symbol-based communication in non-human primates: a C. S. Peirce's semiotic analysis

Are (or were) there any other symbolic species? This question has been addressed by researchers from many different fields and is responsible for a historical controversy on the existence of a threshold between "symbolic creatures" vs "simple forms of language creatures". According to the mainstream ethology and comparative psychology only the Homo sapiens is cognitively equiped to produce and interpret symbols. Here, I introduce an empirically testable model of symbolic semiosis ("symbolic action of sign") supported by C.S.Peirce logical-phenomenological theory of categories. I suggest that a specific sign-user pattern of behavior, observed in non-human primate communication, indicate a transition from indexical to symbolic semiosis.

Primate Communication: By Nature Honest, or by Experience Wise?

We review evolutionary views on honesty and deception and their application to studies of nonhuman primate communication. There is evidence that some primate signals are likely to be accurate on the basis of costliness. They appear most often in contexts that include overtly competitive interactions in which unrelated individuals have limited access to information about one another. However, both game theoretic models and most empirical work suggest that costly signals are not often likely to be the basis for honest communication in nonhuman primates. Inexpensive signaling can exist in contexts wherein communication occurs among related animals, something common among many nonhuman primate societies. Another condition in which inexpensive signaling is possible and that is also typical of nonhuman primates, is when sender and receiver both benefit from coordinated interactions. Additionally, when individuals interact repeatedly and can use past interactions to assess the honesty of signals and to modify future response to signals, low-cost signals can evolve. Nonhuman primates appear to deal with the problem of deception via skeptical responding, which can be largely accounted for by learning rules and the fact that they live in stable social groups and can recognize one another and recall past interactions.

The production and perception of long calls by cotton-top tamarins (Saguinus oedipus): acoustic analyses and playback experiments.

The authors' goal was to provide a better understanding of the relationship between vocal production and perception in nonhuman primate communication. To this end, the authors examined the cotton-top tamarin's (Saguinus oedipus) combination long call (CLC). In Part 1 of this study, the authors carried out a series of acoustic analyses designed to determine the kind of information potentially encoded in the tamarin's CLC. Using factorial analyses of variance and multiple discriminant analyses, the authors explored whether the CLC encodes 3 types of identity information: individual, sex, and social group. Results revealed that exemplars could be reliably assigned to these 3 functional classes on the basis of a suite of spectrotemporal features. In Part 2 of this study, the authors used a series of habituation-dishabituation playback experiments to test whether tamarins attend to the encoded information about individual identity. The authors 1st tested for individual discrimination when tamarins were habituated to a series of calls from 1 tamarin and then played back a test call from a novel tamarin; both opposite- and same-sex pairings were tested. Results showed that tamarins dishabituated when caller identity changed but transferred habituation when caller identity was held constant and a new exemplar was played (control condition). Follow-up playback experiments revealed an asymmetry between the authors' acoustic analyses of individual identity and the tamarins' capacity to discriminate among vocal signatures; whereas all colony members have distinctive vocal signatures, we found that not all tamarins were equally discriminable based on the habituation-dishabituation paradigm.

Selective Phonotaxis by Cotton-Top Tamarins (Saguinus Oedipus)

When nonhuman animals vocalize, signal receivers are provided with a range of potential acoustic information concerning the signaler's body size, sex, individual identity, kinship and group membership. Here we explore whether cotton-top tamarins (Saguinus oedipus) extract such information from their species-typical combination long call using a modification of the phonotaxis assay originally designed for studies of anurans and insects. In each trial, we sequentially played long calls produced by two different individuals and then provided test subjects the choice to approach either speaker location. We quantified selective phonotaxis using two different aspects of subjects' behavioural response: the first approach following stimulus presentation and the total number of times subjects approached toward each speaker location. Results from subjects' first approach indicated that tamarins perceived acoustic differences between long calls produced by cagemates, non-cagemate colony members and foreign tamarins. Specifically, males showed a preference to approach foreign females over familiar ones, while females approached cagemate and homeroom males over foreign males. When the total number of approaches made towards each stimulus was analyzed, results revealed that subjects did not selectively approach cagemates over colony members or colony members over foreign tamarins. Subjects did, however, approach cagemates significantly more often than foreign tamarins. Overall, these results suggest that (i) tamarins are able to use acoustic information encoded within a single vocal signal to assess individuality and degree of familiarity, and (ii) the phonotaxis assay, successfully used in research on anuran and insects, is also a powerful tool for studies of nonhuman primate communication.

Medial prefrontal cortices are unified by common connections with superior temporal cortices and distinguished by input from memory-related areas in the rhesus monkey.

Medial prefrontal cortices in primates have been associated with emotion, memory, and complex cognitive processes. Here we investigated whether the pattern of cortical connections could indicate whether the medial prefrontal cortex constitutes a homogeneous region, or if it can be parceled into distinct sectors. Projections from medial temporal memory-related cortices subdivided medial cortices into different sectors, by targeting preferentially caudal medial areas (area 24, caudal 32 and 25), to a lesser extent rostral medial areas (rostral area 32, areas 14 and 10), and sparsely area 9. Area 9 was distinguished by its strong connections with premotor cortices. Projections from unimodal sensory cortices reached preferentially specific medial cortices, including a projection from visual cortices to area 32/24, from somatosensory cortices to area 9, and from olfactory cortices to area 14. Medial cortices were robustly interconnected, suggesting that local circuits are important in the neural processing in this region. Medial prefrontal cortices were unified by bidirectional connections with superior temporal cortices, including auditory areas. Auditory pathways may have a role in the specialization of medial prefrontal cortices in species-specific communication in non-human primates and language functions in humans.

Language rights—interests of state, language groups and the individual

This article introduces a special issue on mechanisms in language evolution research. It describes processes relevant for the emergence of protolanguage and the transition thereof to modern language. Protolanguage is one of the key terms in the field of language evolution, used to designate a hypothesised intermediate stage in the emergence of language present in extinct hominins: qualitatively different from non-human primate communication in possessing some, but not all, of the features that characterise modern language. Much debate in language evolution focuses on the exact delineation of these features, as well as the means whereby the transitions occurred: first from non-human primate communication systems to protolanguage, and then from protolanguage to modern language. In what follows, we first propose a comprehensive typology of protolanguage debates, taking into account the postulated structural organisation of protolanguage, its functions, and its communicative modality. This makes it possible to show how a specific focus on mechanisms and processes deemed relevant for the emergence of these features allows us to assess the explanatory scope of the existing theories of protolanguage.

How Do Monkeys Look at Faces?

Facial displays are an important form of social communication in nonhuman primates. Clues to the information conveyed by faces are the temporal and spatial characteristics of ocular viewing patterns to facial images. The present study compares viewing patterns of four rhesus monkeys (Macaca mulatta) to a set of 1- and 3-sec video segments of conspecific facial displays, which included open-mouth threat, lip-smack, yawn, fear-grimace, and neutral profile. Both static and dynamic video images were used. Static human faces displaying open-mouth threat, smile, and neutral gestures were also presented. Eye position was recorded with a surgically implanted eye-coil. The relative perceptual salience of the eyes, the midface, and the mouth across different expressive gestures was determined by analyzing the number of eye movements associated with each feature during static and dynamic presentations. The results indicate that motion does not significantly affect the viewing patterns to expressive facial displays, and when given a choice, monkeys spend a relatively large amount of time inspecting the face, especially the eyes, as opposed to areas surrounding the face. The expressive nature of the facial display also affected viewing patterns in that threatening and fear-related displays evoked a pattern of viewing that differed from that recorded during the presentation of submissive-related facial displays. From these results we conclude that (1) the most important determinant of the visual inspection patterns of faces is the constellation of physiognomic features and their configuration, but not facial motion, (2) the eyes are generally the most salient facial feature, and (3) the agonistic or affiliative dimension of an expressive facial display can be delineated on the basis of viewing patterns.

Behavioral mechanisms underlying vocal communication in nonhuman primates

In the wild, nonhuman primate vocalizations signal the presence of different predators, provide information about the group’s location and movement, facilitate friendly interactions, and lead to reconciliation between individuals who have recently exchanged aggression. Current research examines the mechanisms that underlie such communication. Playback experiments demonstrate that subjects treat vocalizations as semantic signals, in the sense that they compare signals according to their referents and not just their acoustic properties. Results provide no evidence, however, that subjects recognize one another’s mental states. Calls that provide information about the group’s location or movement are given by baboons only when they themselves are lost; individuals at the group’s center apparently do not call to inform peripheral animals of their location. Calls that lead to reconciliation are best explained by assuming that callers and recipients have learned, through experience, that a vocalization is rarely followed by aggression and often followed by friendly behavior. The inability of animals to recognize what other individuals know, believe, or desire constitutes a fundamental difference between nonhuman primate vocal communication and human language.

Primate vocal communication as “a window of the mind”

Most studies about mental abilities in nonhuman primates have been held in laboratory conditions. Considering the highy developed social organization of the primate species, however, it is necessary to study about their mental abilities in free-ranging conditions. Numerous studies have been made on natural vocal communication of nonhuman primates. Results of the studies tell mental abilities of nonhuman primates as well as functional significance of vocalizations in their lfe. This paper reviews some studies about nonhuman primate vocal communication and shows examples of mental abilities emerged in these studies, which is recognition of other individuals, perception of quantity, understanding of causal reasoning, categorization, and ability of deception.

Treating people as objects, agents, or "subjects": how young children with and without autism make requests.

A procedure previously used to investigate imperative communication in non-human primates was applied to young children, some of whom had autism. The goal was to examine closely how requests are made in a problem-solving situation. Each child's spontaneous strategies to obtain an out-of-reach object were analyzed in terms of the ways in which he or she used the adult who was present. Results showed that fewer children with autism used a strategy of treating the person as a "subject", and that more children with autism used object-centred strategies.