Language’s intentional nature has been highlighted as a crucial feature distinguishing it from other communication systems. Specifically, language is often thought to depend on highly structured intentional action and mutual mindreading by a communicator and recipient. Whilst similar abilities in animals can shed light on the evolution of intentionality, they remain challenging to detect unambiguously. We revisit animal intentional communication and suggest that progress in identifying analogous capacities has been complicated by (i) the assumption that intentional (that is, voluntary) production (...) of communicative acts requires mental-state attribution, and (ii) variation in approaches investigating communication across sensory modalities. To move forward, we argue that a framework fusing research across modalities and species is required. We structure intentional communication into a series of requirements, each of which can be operationalised, investigated empirically, and must be met for purposive, intentionally communicative acts to be demonstrated. Our unified approach helps elucidate the distribution of animal intentional communication and subsequently serves to clarify what is meant by attributions of intentional communication in animals and humans. (shrink)

A previous observational study suggested that when faced with a partner with its back turned, chimpanzees tend to move around to the front of a non-attending partner and then gesture — rather than gesturing once to attract attention and then again to convey a specific intent. We investigated this preference experimentally by presenting six orangutans, five gorillas, nine chimpanzees, and four bonobos with a food begging situation in which we varied the body orientation of an experimenter with respect to the (...) subject and the location of the food. These manipulations allowed us to measure whether subjects preferred to move around to face E or to use signals to attract her attention before they begged for food. Results showed that all species moved around to face E and then produced visual gestures, instead of using tactile/ auditory gestures behind E to call her attention. Species differences were apparent particularly when the food and E were in different locations. Unlike gorillas and orangutans, chimpanzees and bonobos produced their gestures in front of E in all conditions, including that in which subjects had to leave the food behind to communicate with her. Implications of these results are discussed in the context of the evolution of social cognition in great apes. (shrink)

In contrast to apes’ seemingly sophisticated skill at producing pointing gestures referentially, the comprehension of other individual’s pointing gestures as a source of indexical information seems to be less pronounced.One reason for apes’ difficulty at comprehending pointing gestures might be that in former studies they were mainly confronted with human declarative pointing gestures, whereas apes have largely been shown to point imperatively and towards humans. In the present study bonobos, chimpanzees and orangutans were confronted with a conspecific’s imperative pointing gesture (...) in a competitive context, therefore mirroring former studies that have investigated apes’ skills at producing these gestures.However, apes in the present study did not use their conspecific’s pointing gestures. Apes have been shown to use indexical information when provided noncommunicatively and to interpret other individuals’ actions in terms of motives. Thus, it is discussed whether apes treat a pointing gesture as intentional act of indexical reference. (shrink)

A previous observational study suggested that when faced with a partner with its back turned, chimpanzees tend to move around to the front of a non-attending partner and then gesture — rather than gesturing once to attract attention and then again to convey a specific intent. We investigated this preference experimentally by presenting six orangutans, five gorillas, nine chimpanzees, and four bonobos with a food begging situation in which we varied the body orientation of an experimenter with respect to the (...) subject and the location of the food. These manipulations allowed us to measure whether subjects preferred to move around to face E or to use signals to attract her attention before they begged for food. Results showed that all species moved around to face E and then produced visual gestures, instead of using tactile/ auditory gestures behind E to call her attention. Species differences were apparent particularly when the food and E were in different locations. Unlike gorillas and orangutans, chimpanzees and bonobos produced their gestures in front of E in all conditions, including that in which subjects had to leave the food behind to communicate with her. Implications of these results are discussed in the context of the evolution of social cognition in great apes. (shrink)

We present a new road map for research on “How the Brain Got Language” that adopts an EvoDevoSocio perspective and highlights comparative neuroprimatology – the comparative study of brain, behavior and communication in extant monkeys and great apes – as providing a key grounding for hypotheses on the last common ancestor of humans and monkeys and chimpanzees and the processes which guided the evolution LCA-m → LCA-c → protohumans → H. sapiens. Such research constrains and is constrained by analysis of (...) the subsequent, primarily cultural, evolution of H. sapiens which yielded cultures involving the rich use of language. (shrink)

Despite the variety of theories suggesting how human language might have evolved, very few consider the potential role of emotions in such scenarios. The few existing theories jointly highlight that gaining control over the production of emotional communication was crucial for establishing and maintaining larger social groups. This in turn resulted in the development of more complex social emotions and the corresponding sophisticated socio-cognitive skills to understand others’ communicative behavior, providing the grounds for language to emerge. Importantly, these theories propose (...) that the ability of controlling emotional communication is a uniquely human trait, an assumption that we will challenge. By taking a comparative approach, we discuss recent findings from behavioral and neurobiological studies from our closest relatives, the non-human primates, on the extent of control over their gestural, facial and vocal signals. This demonstrates that research foci differ drastically across these modalities, which further enhances the traditional dichotomy between emotional, involuntary facial and vocal expressions in contrast to intentionally, voluntarily produced gestures. Based on this brief overview, we point to gaps of knowledge in primate communication research and suggest how investigating emotional expressions in our closest relatives might enrich the road map towards the evolution of human language. (shrink)

In contrast to apes' seemingly sophisticated skill at producing pointing gestures referentially, the comprehension of other individual's pointing gestures as a source of indexical information seems to be less pronounced.One reason for apes' difficulty at comprehending pointing gestures might be that in former studies they were mainly confronted with human declarative pointing gestures, whereas apes have largely been shown to point imperatively and towards humans. In the present study bonobos, chimpanzees and orangutans were confronted with a conspecific's imperative pointing gesture (...) in a competitive context, therefore mirroring former studies that have investigated apes' skills at producing these gestures.However, apes in the present study did not use their conspecific's pointing gestures. Apes have been shown to use indexical information when provided noncommunicatively and to interpret other individuals' actions in terms of motives. Thus, it is discussed whether apes treat a pointing gesture as intentional act of indexical reference. (shrink)

Before claiming major differences between the communication systems of humans and other species, it is necessary to (1) overcome methodological limitations in the comparative study of communicative intentions; (2) account for mechanisms other than epistemic vigilance that may also sustain complex forms of communication; and (3) better differentiate between motivational and cognitive factors potentially affecting the emergence of open-ended communication.

In contrast to apes’ seemingly sophisticated skill at producing pointing gestures referentially, the comprehension of other individual’s pointing gestures as a source of indexical information seems to be less pronounced.One reason for apes’ difficulty at comprehending pointing gestures might be that in former studies they were mainly confronted with human declarative pointing gestures, whereas apes have largely been shown to point imperatively and towards humans. In the present study bonobos, chimpanzees and orangutans were confronted with a conspecific’s imperative pointing gesture (...) in a competitive context, therefore mirroring former studies that have investigated apes’ skills at producing these gestures.However, apes in the present study did not use their conspecific’s pointing gestures. Apes have been shown to use indexical information when provided noncommunicatively and to interpret other individuals’ actions in terms of motives. Thus, it is discussed whether apes treat a pointing gesture as intentional act of indexical reference. (shrink)

We present a new road map for research on “How the Brain Got Language” that adopts an EvoDevoSocio perspective and highlights comparative neuroprimatology – the comparative study of brain, behavior and communication in extant monkeys and great apes – as providing a key grounding for hypotheses on the last common ancestor of humans and monkeys and chimpanzees and the processes which guided the evolution LCA-m → LCA-c → protohumans → H. sapiens. Such research constrains and is constrained by analysis of (...) the subsequent, primarily cultural, evolution of H. sapiens which yielded cultures involving the rich use of language. (shrink)

The gestural repertoire of captive gorillas contains the so-called “hand-on“ (or “pat-off“) gesture in which one animals puts its flat hand on top of another's head, which often leads to cessation of the receiver's previous activity. We investigate the origins of this gesture and developmental aspects of gesture creation. We further analyze gesture form and use in relation to the age of the sender with special consideration of the reaction of the receiver to better explain the function of the hand-on. (...) The focus of the study is to compare this gesture across different age groups in gorillas in regard to both production and reception and to get insights into possible origins of the gesture. (shrink)

The gestural repertoire of captive gorillas contains the so-called “hand-on” gesture in which one animals puts its flat hand on top of another’s head, which often leads to cessation of the receiver’s previous activity. We investigate the origins of this gesture and developmental aspects of gesture creation. We further analyze gesture form and use in relation to the age of the sender with special consideration of the reaction of the receiver to better explain the function of the hand-on. The focus (...) of the study is to compare this gesture across different age groups in gorillas in regard to both production and reception and to get insights into possible origins of the gesture. (shrink)