From silent gesture to artificial sign languages


Language evolution can be described as the transition from something that is not language to something that is language. This definition allows us to remain agnostic about the mechanisms (biological or cultural) involved in the emergence of language. Moreover, the definition marks the boundary between language evolution and language change: the latter is a process that takes place when there is already a language (see the description in Scott-Phillips & Kirby 2010). Finally, language evolution is not something that only happened in pre-history: the emergence of new languages can be observed in the present day, with newly-emerging sign languages providing the best example of such a process. In this paper we will sketch a methodology to study the transition from no-language to language. More specifically, we will show how combining different laboratory methods will allow us to observe the transition from ‘silent gesture’(the behaviour observed in naive hearing participants who are asked to convey meanings while using only gesture) to artificial sign language. By allowing silent gesturing participants to interact and learn from one another via iterated learning, artificial sign languages emerge which, we will claim, share crucial properties with existing languages. Thus, the emergence of artificial sign language in the lab can help us to understand some of the mechanisms involved in the emergence of language in the human species.