Language Evolution and Computation Bibliography

Two decades of attempts to model the emergence of language as a collective cognitive activity have demonstrated a number of principles that might have been part of the historical process that led to language. Several models have demonstrated the emergence of structure in a symbolic medium, but none has demonstrated the emergence of the capacity for symbolic representation. The current shift in cognitive science toward theoretical frameworks based on embodiment is already furnishing computational models with additional mechanisms relevant to the emergence of symbolic language. An analysis of embodied interaction among captive, but not human-enculturated, bonobo chimpanzees reveals a number of additional features of embodiment that are relevant to the emergence of symbolic language, but that have not yet been explored in computational simulation models; for example, complementarity of action in addition to imitation, iconic in addition to indexical gesture, coordination among multiple sensory and perceptual modalities, and the orchestration of intra- and inter-individual motor coordination. The bonobos provide an evolutionarily plausible intermediate stage in the development of symbolic expression that can inform efforts to model the emergence of symbolic language.

We present a connectionist model that demonstrates how propositional structure can emerge from the interactions among the members of a community of simple cognitive agents. We first describe a process in which agents coordinating their actions and verbal productions with each other in a shared world leads to the development of propositional structures. We then present a simulation model which implements this process for generating propositions from scratch. We report and discuss the behaviour of the model in terms of its ability to produce three properties of propositions: (1) a coherent lexicon characterised by shared form-meaning mappings; (2) conventional structure in the sequences of forms; (3) the prediction of spatial facts. We show that these properties do not emerge when a single individual learns the task alone and conclude that the properties emerge from the demands of the communication task rather than from anything inside the individual agents. We then show that the shared structural principles can be described as a grammar, and discuss the implications of this demonstration for theories concerning the origins of the structure of language.

In this paper, we elaborate upon the framework by considering more explicitly the problem of creating shared symbolic structure. A lexicon is (among other things) a set of public structures for denoting or implicating shared meanings. In other words, the existence of a lexicon requires the sharing of forms and meanings -- and mappings between these -- among members of an interacting population of agents. Leaving aside cosmic and theological events which could create such an outcome, how could a lexicon come to be? The solution provided here is based upon a convergence of agents' schemes for classifying visual phenomena. All agents have a capacity for such classification, but convergence upon a singular scheme is shaped by the constraints for consensus when employing the scheme in interaction with other agents.

In this paper, we introduce a framework for simulating cultural process. The general idea is to simulate a world in which learning agents create external structures which mediate their behavior. This simulation demonstrates the simple (but very important) concept that such a system is capable, through generations of time, of producing agents endowed with cognitive powers that are not attainable in the lifetime of any individual agent. We argue that such an outcome is possible without effecting the genetic organization of individuals. However, we also argue that the cultural process is capable of guiding both learning and phylogenetic evolution, which leaves open the possiblity of genetic organization tracking cultural process.