Cognitive constraints on vocal combinatoriality in a social bird
Stuart K. Watson,
Joseph G. Mine,
Louis G. O’Neill,
Jutta L. Mueller,
Andrew F. Russell,
Simon W. Townsend
Affiliations
Stuart K. Watson
Department of Comparative Language Science, University of Zurich, Zurich, Switzerland; Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich, Switzerland; Center for the Interdisciplinary Study of Language Evolution, Zurich, Switzerland; Corresponding author
Joseph G. Mine
Department of Comparative Language Science, University of Zurich, Zurich, Switzerland; Center for the Interdisciplinary Study of Language Evolution, Zurich, Switzerland; Faculty of Environment, Science and Economy, University of Exeter, Penryn, Cornwall TR10 9FE, UK
Louis G. O’Neill
Faculty of Environment, Science and Economy, University of Exeter, Penryn, Cornwall TR10 9FE, UK; Department of Biological Sciences, Macquarie University, North Ryde, NSW 2109 Australia; Fowlers Gap Arid Zone Research Station, School of Biological, Earth & Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
Jutta L. Mueller
Institute of Linguistics, University of Vienna, Vienna, Austria
Andrew F. Russell
Faculty of Environment, Science and Economy, University of Exeter, Penryn, Cornwall TR10 9FE, UK; Institute of Linguistics, University of Vienna, Vienna, Austria; Fowlers Gap Arid Zone Research Station, School of Biological, Earth & Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia
Simon W. Townsend
Department of Comparative Language Science, University of Zurich, Zurich, Switzerland; Center for the Interdisciplinary Study of Language Evolution, Zurich, Switzerland; Department of Psychology, University of Warwick, Coventry, UK
Summary: A critical component of language is the ability to recombine sounds into larger structures. Although animals also reuse sound elements across call combinations to generate meaning, examples are generally limited to pairs of distinct elements, even when repertoires contain sufficient sounds to generate hundreds of combinations. This combinatoriality might be constrained by the perceptual-cognitive demands of disambiguating between complex sound sequences that share elements. We test this hypothesis by probing the capacity of chestnut-crowned babblers to process combinations of two versus three distinct acoustic elements. We found babblers responded quicker and for longer toward playbacks of recombined versus familiar bi-element sequences, but no evidence of differential responses toward playbacks of recombined versus familiar tri-element sequences, suggesting a cognitively prohibitive jump in processing demands. We propose that overcoming constraints in the ability to process increasingly complex combinatorial signals was necessary for the productive combinatoriality that is characteristic of language to emerge.
