The co-evolution of language and mindreading
Marieke Woensdregt (Edinburgh)
Tuesday 18 October 2016, 11:00–12:30
1.17 Dugald Stewart Building
The hypothesis that mindreading (theory of mind) and language have facilitated or pushed for each other’s evolution has been put forward in several different ways on several different grounds. The evolution of explicit mindreading skills may have been important for the evolution of language because it allows us to express and recognize communicative intentions. The evolution of linguistic conventions may have been important for the evolution of mindreading because it allows us to make our mental states explicit, and transmit our understanding of mental states to others. The same arguments have been made on the developmental timescale – based on studies correlating mindreading skills with word learning ability, and studies showing that certain linguistic input can facilitate the development of mindreading.
In this talk I will present an agent-based model that explores under which circumstances language and mindreading can co-evolve – where language is implemented as lexicon-learning, and mindreading as the ability to learn another agent’s perspective on the world. Agents can learn both the lexicon and the perspective of another agent through Bayesian inference, but these two skills crucially bootstrap each other during development – meaning that one skill could not be learned if there was no ability to learn the other.
Over the course of iterated learning this co-development results in interesting evolutionary dynamics. Populations of agents that develop in this way are only able to establish an informative language if there is either a strong pressure in favour of expressivity, or a weak pressure that favours successful perspective-takers as cultural parents. Given such a weak pressure in favour of perspective-taking, an informative language can be established even when learners have a strong cognitive bias in favour of simple (compressible) languages. I will discuss these simulation results in the light of theories about the evolution of Gricean communication and social coordination.