Simplicity and Expressivity Compete in Cultural Evolution : Linguistic Structure is the Result by Simon KIRBY (University of Edinburgh, UK)
Language, like other human behaviours, exhibits striking systematic structure. For example, two central design features of human language are the way in which sentences are composed of recombinable words, and the way in which those words in turn are created out of combinations of reusable sounds. These properties make language unique among communication systems and enable us to convey an open-ended array of messages.
Recently, researchers have turned to cultural evolution as a possible mechanism to explain systematic structure such as this in language. In this talk, I will briefly present a series of experiments and a computational model that demonstrate why this is a promising avenue for research. Using diffusion chain methods in the laboratory, we can observe how behaviour evolves as it is transmitted through repeated cycles of learning and production (a process known as ""iterated learning""). Across a wide range of experimental contexts, we observe an apparent universal: behaviour transmitted by iterated learning becomes increasingly compressible. When combined with a pressure to also be expressive, this may be sufficient to deliver up the structural design features of language.
Although this work is focussed on human language as a test case, the conclusions are quite general. Cultural transmission by iterated learning is an adaptive process that delivers systematic structure for free.
