Gesture - Volume 5, Issue 1-2, 2005

The human brain has mechanisms that can support production and perception of language. We ground the evolution of these mechanisms in primate systems that support manual dexterity, especially the mirror system that integrates execution and observation of hand movements. We relate the motor theory of speech perception to the mirror system hypothesis for language and evolution; explore links between manual actions and speech; contrast “language” in apes with language in humans; show in what sense the “syntax” implemented in Broca’s area is a “motor syntax” far more general than the syntax of linguistics; and relate communicative goals to sentential form.

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.

The present study compared the frequency and contextual usage of the most prominent gestural signals of dominance, submission, affiliation, and bonding in rhesus, pigtail, and stumptail macaques living in captivity. Most similarities among species were found in signals of dominance and submission and most differences in affiliative gestures and bonding patterns. Rhesus macaques have a relatively poor gestural repertoire, pigtail macaques possess conspicuous signals of affiliation and bonding, and stumptail macaques have the richest repertoire of assertive and submissive signals. The similarities and differences in the gestural repertoires of rhesus, pigtail, and stumptail macaques can be related to the intragroup social dynamics of these species as well as to their evolutionary history.

It is well-established that chimpanzees vocalize more in the presence of relatively large amounts of food. The present study administered four trials in random order to each of 20 chimpanzees: (1) small piece of fruit, placed near to cage (~30 cm.), (2) large piece of fruit, placed near to cage, (3) small piece of fruit, placed far from cage (~130 cm.), and (4) large piece of fruit, placed far from cage. On arrival of an experimenter, the chimpanzees not only vocalized more in the presence of the large piece of fruit, confirming previous studies’ findings, but also exhibited more multimodal behavior (vocalizations, manual gestures, and gaze alternation between the food and the experimenter), which extends previous research. More gaze alternation was exhibited to food placed more peripherally. Arousal may be indexed in this species by the number of modalities in which they communicate.

Captive monkeys and apes almost inevitably develop gestures to request food and objects from humans. One possibility is that these gestures are just conditioned responses without any understanding of the socio-cognitive causality underlying their efficacy. A second possibility is that they do involve some understanding of how they are (or fail to be) effective upon the behaviour of others. Observational evidence suggest that most apes and some monkeys coordinate their request gestures with joint attention behaviours — a criterion for early referential communication in human infants. However, experimental evidence about apes and monkeys‘ understanding of the causal role of joint attention in gestural communication is equivocal, with test pass and failure patterns that can be due to cognitive and/or motivational factors. Current evidence suggests that the gestures of apes and monkeys can neither be dismissed as simple conditioned responses nor be uncritically accepted as fully equivalent to human gestures.

Evolutionary and developmental (Evo-Devo) biologists study the interaction between genetic endowment and developmental environment (Lewontin, 2001; Robert, 2004). Cross-fostering is a powerful tool for studying Evo-Devo. Chimpanzees lived under conditions very similar to the conditions of human children with human foster families who used American Sign Language (ASL) exclusively in their presence. In this environment, cross-fostered chimpanzees acquired and used signs as human children do. Intensive analyses of extensive video records of casual conversation show that Tatu at 46–48 months directionally modulated action signs to indicate actor and instrument as human signers do. Tatu directionally modulated action signs in responses to Wh-questions such as “Who?” but directional modulations failed to appear in responses to What Demonstrative questions such as “What that?” These results confirm and extend previous results for Dar at 37–48 months. Further analyses show that Tatu also quantitatively modulated all types of signs to indicate intensity as human signers do.

This paper investigates infant pointing at 12 months. Three recent experimental studies from our lab are reported and contrasted with existing accounts on infant communicative and social-cognitive abilities. The new results show that infant pointing at 12 months already is a communicative act which involves the intentional transmission of information to share interest with, or provide information for other persons. It is argued that infant pointing is an inherently social and cooperative act which is used to share psychological relations between interlocutors and environment, repairs misunderstandings in proto-conversational turn-taking, and helps others by providing information. Infant pointing builds on an understanding of others as persons with attentional states and attitudes. Findings do not support lean accounts on early infant pointing which posit that it is initially non-communicative, does not serve the function of indicating, or is purely self-centered. It is suggested to investigate the emergence of reference and the motivation to jointly engage with others also before pointing has emerged.

The present study reports empirical longitudinal data on the early stages of language development. The main hypothesis is that the output systems of speech and gesture may draw on underlying brain mechanisms common to both language and motor functions. We analyze the spontaneous interaction with their parents of three typically-developing children (2 M, 1 F) videotaped monthly at home between 10 and 23 months of age. Data analyses focused on the production of actions, representational and deictic gestures and words, and gesture-word combinations. Results indicate that there is a continuity between the production of the first action schemes, the first gestures and the first words produced by children. The relationship between gestures and words changes over time. The onset of two-word speech was preceded by the emergence of gesture-word combinations. The results are discussed in order to integrate and support the evolutionary and neurophysiological views of language origins and development.

This study aims to contribute to a clearer understanding of children’s developing gesture-speech system examining the interrelation between deictic and representational elements of gestural and vocal types. We analyze the spontaneous productions of six children, observed longitudinally from 12 to 24 months during the transition from one- to two- and multielement vocal utterances. We focus on children’s gestural and vocal repertoires, and one- and two-element utterances encoding different information within and across modalities. Results indicate that deictic and representational elements are unevenly distributed in the gestural vs. the vocal modality, and in one vs. two-element utterances, with patterns that differ from those observed in the adult gesture-speech system. In these early stages speech and gesture are interrelated primarily through deictic gestures, and representational abilities appear to be markedly more constrained in the gestural as compared to the vocal modality.

The entire bodily gestural repertoire of four different infant groups was coded over the age period of 9 to 15 months. Two small samples of English-Canadian and Parisian-French infants were filmed every two weeks at home. A larger sample of Japanese infants was visited for 7 sessions and of Italian-Canadian infants for 4 sessions at 9 months and 15 months and again at 3 years. Language measures were collected for the last two groups. Increases in Comment gestures, particularly pointing, in Object exchange gestures, and in Agency gestures were found across almost all groups. Decreases in Reach-request and in Emotive gestures were also found for most groups. The increasing group of gestures was positively related to vocabulary acquisition, particularly to receptive vocabulary. Reach-request and Protest gestures at 15 months were negative related to different aspects of language at 3 years. The importance of examining the entire nonverbal communicative repertoire across cultures is discussed in terms of assessing the relationship of gestures to language acquisition. Changes in the gestural repertoire appear to be universal across infants of different cultures, at least those examined.

What are the relations between linguistic encoding and gestural representations of events during online speaking? The few studies that have been conducted on this topic have yielded somewhat incompatible results with regard to whether and how gestural representations of events change with differences in the preferred semantic and syntactic encoding possibilities of languages. Here we provide large scale semantic, syntactic and temporal analyses of speech- gesture pairs that depict 10 different motion events from 20 Turkish and 20 English speakers. We find that the gestural representations of the same events differ across languages when they are encoded by different syntactic frames (i.e., verb-framed or satellite-framed). However, where there are similarities across languages, such as omission of a certain element of the event in the linguistic encoding, gestural representations also look similar and omit the same content. The results are discussed in terms of what gestures reveal about the influence of language specific encoding on on-line thinking patterns and the underlying interactions between speech and gesture during the speaking process.

Gesture is typically produced with speech, forming a fully integrated system with that speech. However, under unusual circumstances, gesture can be produced completely on its own — without speech. In these instances, gesture takes over the full burden of communication usually shared by the two modalities. What happens to gesture in these two very different contexts? One possibility is that there are no differences in the forms gesture takes in these two contexts — that gesture is gesture no matter what its function. But, in fact, that’s not what we find. When gesture is produced on its own, it assumes the full burden of communication and takes on a language-like form, with sentence-level ordering rules, word-level paradigms, and grammatical categories. In contrast, when gesture is produced in conjunction with speech, it shares the burden of communication with speech and takes on a global imagistic form, often conveying information not found anywhere in speech. Gesture thus changes its form according to its function.

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.