The Emergence of Modern Communication in Primates: A Computational Approach

Abstract

It is biological structures (and their activities), and not the diverse functions they contribute to (i.e., forms of behavior), that evolve. We believe that the long-lasting controversy around when modern language appeared would benefit from a shift of focus, from ``communication{''} to ``computation.{''} Computation is the activity performed by specific neural devices. Computational devices (and their neurobiological correlates), but not communication devices, have a common evolutionary history. We further expect that computational devices are functionally coupled to different interface systems, thus rendering diverse kinds of outputs and eventually contributing to different functions (forms of behaviors). Multiple evidence (genetic, neurobiological, clinical, archeological, fossil, and ethological) suggest that the computational device of human language (the faculty of language in the narrow sense, after Chomsky) is an evolutionary novelty that appeared along with anatomically modern humans. Importantly, this does not preclude that other extinct hominins had ``language.{''} It is just that the strings of symbols they were plausibly able to produce lacked certain structural properties that we can only find in extant oral or sign languages. Hominin oral ``languages{''} (or better perhaps, ``protolanguages{''}) could have replaced signed ``languages{''} at some early period during hominin evolution. Nonetheless, the gestural ``languages{''} (or better, ``protolanguages{''}) hypothetically employed by other extinct hominids would have been less structurally complex than extant human languages are.