Higher-Order Musical Temporal Structure in Bird Song

Abstract

Bird songs often display musical acoustic features such as tonal pitch selection, rhythmicity, and melodic contouring. We investigated higher-order musical temporal structure in bird song using an experimental method called “music scrambling” with human subjects. Recorded songs from a phylogenetically diverse group of 20 avian taxa were split into constituent elements (“notes” or “syllables”) and recombined in original and random order. Human subjects were asked to evaluate which version sounded more “musical” on a per-species basis. Species identity and stimulus treatment were concealed from subjects, and stimulus presentation order was randomized within and between taxa. Two recordings of human music were included as a control for attentiveness. Participants varied in their assessments of individual species musicality, but overall they were significantly more likely to rate bird songs with original temporal sequence as more musical than those with randomized temporal sequence. We discuss alternative hypotheses for the origins of avian musicality, including honest signaling, perceptual bias, and arbitrary aesthetic coevolution.

Cultural evolution and music

“…Humpback whales also have hierarchical rhythmic structures that are like those found in human music (Handel et al, 2009;Kello et al, 2017). Additionally, bird song and human music appear to be shaped by similar motor constraints (Savage et al, 2017;Tierney et al, 2011;Ammirante and Russo, 2015), and when bird songs are shu ed they are less likely to be classi ed as "musical" by human listeners (Bilger et al, 2021). Below, we will brie y review some recent research on the cultural evolution of non-human song that we feel will be relevant to cultural evolution researchers.…”

Cultural Evolution and Music

“…Humpback whales also have hierarchical rhythmic structures that are like those found in human music (Handel et al, 2009;Kello et al, 2017). Additionally, bird song and human music appear to be shaped by similar motor constraints (Savage et al, 2017;Tierney et al, 2011;Ammirante and Russo, 2015), and when bird songs are shu ed they are less likely to be classi ed as "musical" by human listeners (Bilger et al, 2021). Below, we will brie y review research on the cultural evolution of non-human song relevant to cultural evolution researchers.…”

Notions of arbitrariness

“…12 Comparable appeals to arbitrariness-talk can be found in work on other species. For instance, Bilger et al (2021) argue that the temporal structure of some birdsongs is not "arbitrary" since it evolved to exercise an "aesthetic impact" upon receivers. As these examples suggest, lack of motivatedness can be absolute or comparative.…”