We propose that the crucial difference between human cognition and that of other species is the ability to participate with others in collaborative activities with shared goals and intentions: shared intentionality. Participation in such activities requires not only especially powerful forms of intention reading and cultural learning, but also a unique motivation to share psychological states with others and unique forms of cognitive representation for doing so. The result of participating in these activities is species-unique forms of cultural cognition and (...) evolution, enabling everything from the creation and use of linguistic symbols to the construction of social norms and individual beliefs to the establishment of social institutions. In support of this proposal we argue and present evidence that great apes understand the basics of intentional action, but they still do not participate in activities involving joint intentions and attention. Human children's skills of shared intentionality develop gradually during the first 14 months of life as two ontogenetic pathways intertwine: the general ape line of understanding others as animate, goal-directed, and intentional agents; and a species-unique motivation to share emotions, experience, and activities with other persons. The developmental outcome is children's ability to construct dialogic cognitive representations, which enable them to participate in earnest in the collectivity that is human cognition. Key Words: collaboration; cooperation; cultural learning; culture; evolutionary psychology; intentions; shared intentionality; social cognition; social learning; theory of mind; joint attention. (shrink)

In this enlightening exploration of our nearest primate relatives, Michael Tomasello and Josep Call address the current state of our knowledge about the cognitive skills of non-human primates and integrate empirical findings from the beginning of the century to the present.

From the first months of life, human infants produce “protophones,” speech-like, non-cry sounds, presumed absent, or only minimally present in other apes. But there have been no direct quantitative comparisons to support this presumption. In addition, by 2 months, human infants show sustained face-to-face interaction using protophones, a pattern thought also absent or very limited in other apes, but again, without quantitative comparison. Such comparison should provide evidence relevant to determining foundations of language, since substantially flexible vocalization, the inclination to (...) explore vocalization, and the ability to interact socially by means of vocalization are foundations for language. Here we quantitatively compare data on vocalization rates in three captive bonobo (Pan paniscus) mother–infant pairs with various sources of data from our laboratories on human infant vocalization. Both humans and bonobos produced distress sounds (cries/screams) and laughter. The bonobo infants also produced sounds that were neither screams nor laughs and that showed acoustic similarities to the human protophones. These protophone-like sounds confirm that bonobo infants share with humans the capacity to produce vocalizations that appear foundational for language. Still, there were dramatic differences between the species in both quantity and function of the protophone and protophone-like sounds. The bonobo protophone-like sounds were far less frequent than the human protophones, and the human protophones were far less likely to be interpreted as complaints and more likely as vocal play. Moreover, we found extensive vocal interaction between human infants and mothers, but no vocal interaction in the bonobo mother–infant pairs—while bonobo mothers were physically responsive to their infants, we observed no case of a bonobo mother vocalization directed to her infant. Our cross-species comparison focuses on low- and moderate-arousal circumstances because we reason the roots of language entail vocalization not triggered by excitement, for example, during fighting or intense play. Language appears to be founded in flexible vocalization, used to regulate comfortable social interaction, to share variable affective states at various levels of arousal, and to explore vocalization itself. (shrink)

Orang-utans played a communication game in two studies testing their ability to produce and comprehend requestive pointing. While the ‘communicator’ could see but not obtain hidden food, the ‘donor’ could release the food to the communicator, but could not see its location for herself. They could coordinate successfully if the communicator pointed to the food, and if the donor comprehended his communicative goal and responded pro-socially. In Study 1, one orang-utan pointed regularly and accurately for peers. However, they responded only (...) rarely. In Study 2, a human experimenter played the communicator’s role in three conditions, testing the apes’ comprehension of points of different heights and different degrees of ostension. There was no effect of condition. However, across conditions one donor performed well individually, and as a group orang-utans’ comprehension performance tended towards significance. We explain this on the grounds that comprehension required inferences that they found difficult – but not impossible. The finding has valuable implications for our thinking about the development of pointing in phylogeny. (shrink)

Chimpanzees follow the gaze of conspecifics and humans — follow it past distractors and behind barriers, ‘check back’ with humans when gaze following does not yield interesting sights, use gestures appropriately depending on the visual access of their recipient, and select different pieces of food depending on whether their competitor has visual access to them. Taken together, these findings make a strong case for the hypothesis that chimpanzees have some understanding of what other individuals can and cannot see. However, chimpanzees (...) do not seem nearly so skillful in the Gesture Choice and Object Choice experimental paradigms. Neither behavioral conditioning nor theory of mind explanations can account for these results satisfactorily. Instead this chapter proposes the idea that chimpanzees have the cognitive skills to recall, represent, categorize, and reason about the behavior and perception of others, but not their intentional or mental states, because they do not know that others have such states since they cannot make a link to their own. Human beings began their own evolutionary trajectory with these same skills, but then at some point in their evolution (probably quite recently) they began to understand that their own experience could serve as some kind of model for that of other persons. This allowed for even better prediction and control of the behavior of others and better communication and cooperation with them as well, and so it was an adaptation with immediate adaptive consequences that ensured its survival. (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)

Communication, when defined as an act intended to affect the psychological state of another individual, demands the use of inference. Either the signaler, the recipient, or both must make leaps of understanding which surpass the semantic information available and draw from pragmatic clues to fully imbue and interpret meaning. While research into human communication and the evolution of language has long been comfortable with mentalistic interpretations of communicative exchanges, including rich attributions of mental state, research into animal communication has balked (...) at theoretical models which describe mentalized cognitive mechanisms. We submit a new theoretical perspective on animal communication: the model of inferential communication. For use when existing proximate models of animal communication are not sufficient to fully explain the complex, flexible, and intentional communication documented in certain species, specifically non-human primates, we present our model as a bridge between shallower, less cognitive descriptions of communicative behavior and the perhaps otherwise inaccessible mentalistic interpretations of communication found in theoretical considerations of human language. Inferential communication is a framework that builds on existing evidence of referentiality, intentionality, and social inference in primates. It allows that they might be capable of applying social inferences to a communicative setting, which could explain some of the cognitive processes that enable the complexity and flexibility of primate communication systems. While historical models of animal communication focus on the means-ends process of behavior and apparent cognitive outcomes, inferential communication invites consideration of the mentalistic processes that must underlie those outcomes. We propose a mentalized approach to questions, investigations, and interpretations of non-human primate communication. We include an overview of both ultimate and proximate models of animal communication, which contextualize the role and utility of our inferential communication model, and provide a detailed breakdown of the possible levels of cognitive complexity which could be investigated using this framework. Finally, we present some possible applications of inferential communication in the field of non-human primate communication and highlight the role it could play in advancing progress toward an increasingly precise understanding of the cognitive capabilities of our closest living relatives. (shrink)

Journal Name: Semiotica - Journal of the International Association for Semiotic Studies / Revue de l'Association Internationale de Sémiotique Volume: 2014 Issue: 198 Pages: 205-240.

The previous studies have shown that human infants and domestic dogs follow the gaze of a human agent only when the agent has addressed them ostensively—e.g., by making eye contact, or calling their name. This evidence is interpreted as showing that they expect ostensive signals to precede referential information. The present study tested chimpanzees, one of the closest relatives to humans, in a series of eye-tracking experiments using an experimental design adapted from these previous studies. In the ostension conditions, a (...) human actor made eye contact, called the participant’s name, and then looked at one of two objects. In the control conditions, a salient cue, which differed in each experiment (a colorful object, the actor’s nodding, or an eating action), attracted participants’ attention to the actor’s face, and then the actor looked at the object. Overall, chimpanzees followed the actor’s gaze to the cued object in both ostension and control conditions, and the ostensive signals did not enhance gaze following more than the control attention-getters. However, the ostensive signals enhanced subsequent attention to both target and distractor objects (but not to the actor’s face) more strongly than the control attention-getters—especially in the chimpanzees who had a close relationship with human caregivers. We interpret this as showing that chimpanzees have a simple form of communicative expectations on the basis of ostensive signals, but unlike human infants and dogs, they do not subsequently use the experimenter’s gaze to infer the intended referent. These results may reflect a limitation of non-domesticated species for interpreting humans’ ostensive signals in inter-species communication. (shrink)

Cognitive abilities cannot be measured directly. What we can measure is individual variation in task performance. In this paper, we first make the case for why we should be interested in mapping individual differences in task performance on to particular cognitive abilities: we suggest that it is crucial for examining the causes and consequences of variation both within and between species. As a case study, we examine whether multiple measures of inhibitory control for non-human animals do indeed produce correlated task (...) performance; however, no clear pattern emerges that would support the notion of a common cognitive ability underpinning individual differences in performance. We advocate a psychometric approach involving a three-step programme to make theoretical and empirical progress: first, we need tasks that reveal signature limits in performance. Second, we need to assess the reliability of individual differences in task performance. Third, multi-trait multi-method test batteries will be instrumental in validating cognitive abilities. Together, these steps will help us to establish what varies between individuals that could impact their fitness and ultimately shape the course of the evolution of animal minds. Finally, we propose executive functions, including working memory, inhibitory control and attentional shifting, as a sensible starting point for this endeavour. (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)

Smith et al.'s article provides a convincing argument for devoting increased research attention to comparative metacognition. However, this increased attention should be complemented with establishing links with comparative theory of mind (ToM) research, which are currently missing. I present a task in which pairs of subjects are presented with incomplete information in an object-choice situation that could be used to establish that link.

Ape species-specific communication is grounded on the present, possesses some referential qualities and is mostly used to request objects or actions from others. Artificial systems of communication borrowed from humans transform apes' communicative exchanges by freeing them from the present (i.e. displaced reference) although requests still predominate as the main reason for communicating with others. Symbol use appears to enhance apes' relational abilities and their inhibitory control. Despite these substantial changes, it is concluded that even though artificial communication enhances thought (...) and enables its expression more openly, it does not create it or modify the motivation behind communicative exchanges. (shrink)

Animals react and adjust to the behavior of their conspecifics. Much less is known about whether animals also react and adjust to the psychological states of others. Recent evidence suggests that chimpanzees follow the gaze of others around barriers, past distracters, and check back if they find nothing. Chimpanzees can gauge the motives of a human experimenter and distinguish his intentional from accidental actions. These results suggest that chimpanzees interpret the perceptions and actions of others from a psychological perspective -they (...) seem to know what others can and cannot see and what goals others pursue. It is hypothesized that the co-operation of the ability to operate on psychological states and the motivation to share emotions and experiences with others are key ingredients in the making of human minds. (shrink)

Flack and de Waal argue that reciprocity, revenge, and moralistic aggression are important components of the social norms that exist in some non-human primates. These and other phenomena are seen as the evolutionary building blocks of human morality. Although focussing on these phenomena is a good starting point for studying the question of morality in non-human animals, they only provide a partial answer. Two other issues deserve careful attention: perception of intentions, and the distinction between using and perceiving social norms. (...) First, perception of intention is particularly important because it modulates whether retribution is justified. There is some preliminary evidence that may indicate that some primates are sensitive to the behavioural intentions of others. Second, the evidence regarding use of social norms does not necessarily imply that individuals also perceive them . This distinction seems particularly important in any comparative analysis of morality that includes humans. Currently, it is unclear whether non- human animals are capable of perceiving social norms. Future studies should devote more attention to these issues and some possible ways to investigate them are indicated. (shrink)