Context-dependent communication under environmental constraints

There is significant evidence that real-world communication cannot be reduced to sending signals with context- independent meaning. In this work, based on a variant of the classical Lewis (1969) signalling model, we explore the conditions for the emergence of context-dependent communication in an agent-based situated model. In particular, we demonstrate that pressure to minimise the vocabulary size is sufficient for such emergence. At the same time, we study the environmental conditions and cognitive capabilities that enable contextual disambiguation of symbol meanings. We show that (a) regularities in the context are not necessary for context-dependent communication and that (b) environmental constraints on the receiver's referent choice can be unilaterally exploited by the sender, without disambiguation capabilities on the receiver's end. Consistent with common assumptions, the sender's awareness of the context appears to be required for contextual communication. Our results further demonstrate the crucial role of the environment in the seemingly multilayered phenomenon of context-dependent communication - where language is influenced not only by the distribution of objects in the context, as indicated by previous studies, but also by the very presence of environmental constraints on referent choice. The computational model developed in this work is a demonstration of how signals maybe ambiguous out of context, but still allow for near-perfect communication accuracy.