Music recursion: Preliminary experiments on human sensitivity to rhythmic structure in a grammar with recursive self-similarity

Music recursion: Preliminary experiments on human sensitivity to rhythmic structure in a grammar with recursive self-similarity

Andreea Geambașu1  Andrea Ravignani2,  and Clara C. Levelt1

1. Leiden University Centre for Linguistics - Leiden Institute for Brain and Cognition, Leiden University

2. Department of Cognitive Biology, University of Vienna - AI Lab, Vrije Universiteit Brussel

Processing of hierarchical structures has been proposed as a uniquely human ability, a hallmark of the linguistic system that distinguishes human language from animal communication systems. Recursion is often considered the pinnacle of human-specific hierarchical structures. In Artificial Grammar Learning experiments, human participants can learn the context-free grammar AnBn. Yet, whether acquisition of this grammar can be taken as evidence for processing recursive information at all is debated. Here we take an alternative approach, testing recursion in the musical, rhythmic domain. We present the first rhythm detection experiment using a Lindenmayer grammar, a self-similar recursive grammar previously shown to be learnable using speech stimuli. Participants’ sensitivity to recursive rhythmic structure was tested against different types of foils when given implicit vs. explicit instructions. Preliminary results suggest that (i) at the group level, participants were unable to correctly accept or reject grammatical and ungrammatical strings, although (ii) five (of 40) participants were able to do so when given specific instructions. We contrast our findings with results on human sensitivity to recursion in other domains and modalities, proposing additional experiments to test whether humans are particularly apt at processing recursive structures and, if so, whether this is a domain-general ability.