Discreteness and systematicity emerge to facilitate communication in a continuous signal-meaning space

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The Evolution of Language: Proceedings of the 15th International Conference, 2024


Language, although grounded in a continuous substrate, is fundamentally discrete in both its forms and meanings. Moreover, the mappings between these forms and meanings are not only marked by discreteness, but also another foundational feature: systematicity. While previous studies have explored the emergence of these properties independently — with a focus on continuous signaling spaces for discreteness and domains with existing discrete elements for systematicity — here we explore their concurrent emergence by running a two-player communication experiment where participants were asked to generalize learned continuous whistled signals to communicate about a continuous color space. We found that participants learned to communicate successfully and aligned their signal repertoires, with more successful dyads showing higher degrees of alignment. We also found that both systematicity and discreteness emerged and that systematicity was correlated with better communication. Additionally, we note cases where participants seemed to have created composite signals to generalize to unseen colors, inviting speculation about the role of combinatoriality in this domain. Possible future extensions of this work are outlined, including investigating the role of discreteness and extending this setup to a multi-generational transmission experiment.