a b s t r a c t A unique hallmark of human language is that it uses signals that are both learnt and symbolic. The emergence of such signals was therefore a defining event in human cognitive evolution, yet very little is known about how such a process occurs. Previous work provides some insights on how meaning can become attached to form, but a more foundational issue is presently unaddressed. How does a signal signal its own signalhood? That is, how do humans even know that communicative behaviour is indeed communicative in nature? We introduce an experimental game that has been designed to tackle this problem. We find that it is commonly resolved with a bootstrapping process, and that this process influences the final form of the communication system. Furthermore, sufficient common ground is observed to be integral to the recognition of signalhood, and the emergence of dialogue is observed to be the key step in the development of a system that can be employed to achieve shared goals.

Observations of alarm calling behavior in putty-nosed monkeys are suggestive of a link with human language evolution. However, as is often the case in studies of animal behavior and cognition, com-peting theories are underdetermined by the available data. We argue that computational modeling, and in particular the use of individual-based simulations, is an effective way to reduce the size of the pool of candidate explanations. Simulation achieves this both through the classification of evolution-ary trajectories as either plausible or implausible, and by putting lower bounds on the cognitive com-plexity required to perform particular behaviors. A case is made for using both of these strategies to understand the extent to which the alarm calls of putty-nosed monkeys are likely to be a good model for human language evolution.

Human communication is often thought about in terms of transmitted messages in a conventional code like a language. But communication requires a specialized interactive intelligence. Senders have to be able to perform recipient design, while receivers need to be able to do intention recognition, knowing that recipient design has taken place. To study this interactive intelligence in the lab, we developed a new task that taps directly into the underlying abilities to communicate in the absence of a conventional code. We show that subjects are remarkably successful communicators under these conditions, especially when senders get feedback from receivers. Signaling is accomplished by the manner in which an instrumental action is performed, such that instrumentally dysfunctional components of an action are used to convey communicative intentions. The findings have important implications for the nature of the human communicative infrastructure, and the task opens up a line of experimentation on human communication. 1.

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journal homepage: www.elsevier.com/locate/COGNIT

doi: 10.3389/fnhum.2010.00203 Neural insights into the relation between language and communication

journal homepage: www.elsevier.com/locate/COGNIT

To understand and predict the behaviour of others, people regularly reason about others ’ beliefs, goals, and intentions. People can even use this theory of mind recursively, and form beliefs about the way others in turn reason about the beliefs, goals, and intentions of others. Although the evolutionary origins of this cognitively demanding ability are unknown, the Vygotskian intelligence hypothesis suggests that higher-order theory of mind allows individuals to cooperate more effectively. In this paper, we investigate this hypothesis through the Tacit Communication Game. In this game, two agents cooperate to set up novel communication in which a Sender agent communicates the goal to the Receiver agent. By simulating interactions between agents that differ in their theory of mind abilities, we determine to what extent higher orders of theory of mind help agents to set up communication. Our results show that first-order and second-order theory of mind can allow agents to set up communication more quickly, but also that the effectiveness of higher orders of theory of mind depends on the role of the agent. Additionally, we find that in some cases, agents cooperate more effectively if they reason at lower orders of theory of mind.

†These authors contributed equally to this work. Humans have a remarkable capacity for tuning their communicative behaviors to different addressees, a phenomenon also known as recipient design. It remains unclear how this tuning of communicative behavior is implemented during live human interactions. Classical theories of communication postulate that recipient design involves perspective taking, i.e., the communicator selects her behavior based on her hypotheses about beliefs and knowledge of the recipient. More recently, researchers have argued that perspective taking is computationally too costly to be a plausible mechanism in everyday human communication. These researchers propose that computationally simple mechanisms, or heuristics, are exploited to perform recipient design. Such heuristics may be able to adapt communicative behavior to an addressee with no consideration for the addressee’s beliefs and knowledge. To test whether the simpler of the two mechanisms is sufficient for explaining the “how ” of recipient design we studied communicators ’ behaviors in the context of a non-verbal communicative task (the Tacit Communication Game, TCG). We found that the specificity of the observed trial-by-trial adjustments made by communicators is parsimoniously explained by perspective taking, but not by simple heuristics. This finding is important as it suggests that humans do have a computationally efficient way of taking beliefs and knowledge of a recipient into account.

monkey alarm calls to human language: