Chicks Like Consonant Music

Many human musical scales, including the diatonic major scale prevalent in Western music, are built partially or entirely from intervals (ratios between adjacent frequencies) corresponding to small-integer proportions drawn from the harmonic series. Scientists have long debated the extent to which principles of scale generation in human music are biologically or culturally determined. Data from animal "song" may provide new insights into this discussion. Here, by examining pitch relationships using both a simple linear regression model and a Bayesian generative model, we show that most songs of the hermit thrush (Catharus guttatus) favor simple frequency ratios derived from the harmonic (or overtone) series. Furthermore, we show that this frequency selection results not from physical constraints governing peripheral production mechanisms but from active selection at a central level. These data provide the most rigorous empirical evidence to date of a bird song that makes use of the same mathematical principles that underlie Western and many non-Western musical scales, demonstrating surprising convergence between human and animal "song cultures." Although there is no evidence that the songs of most bird species follow the overtone series, our findings add to a small but growing body of research showing that a preference for small-integer frequency ratios is not unique to humans. These findings thus have important implications for current debates about the origins of human musical systems and may call for a reevaluation of existing theories of musical consonance based on specific human vocal characteristics. music | birdsong | overtones M any human musical scales, including the diatonic major scale prevalent in Western music, are built partially or entirely from intervals (ratios between adjacent frequencies) corresponding to small-integer ratios drawn from the harmonic series (1). A long-running debate concerns the extent to which principles underlying the structure of human musical scales derive from biological aspects of auditory perception and/or vocal production or are historical cultural "accidents" (2-4). The songs of nonhuman animals, such as birds or whales, potentially offer a valuable perspective on this debate. On the one hand, features of human music that are culturally bound, or dependent on specific characteristics of the human voice or auditory system, should be absent in animal vocalizations. On the other hand, aspects of human music observed in the vocalizations of other species seem likely to be partially determined by general physical or biological constraints rather than solely by cultural practices. Such shared features would complement recent research suggesting that common motor constraints shape both human song and that of some bird species (5).The physical principles underlying vocal production in songbirds are well understood (6-10) and do not differ fundamentally from those of other vertebrates. Sound is produced by tissue vibrations in the syrinx, a bird-specific organ located at the b...

Section: Resultsmentioning

confidence: 99%

Overtone-based pitch selection in hermit thrush song: Unexpected convergence with scale construction in human music

Doolittle

Gingras

Endres

et al. 2014

“…Finally, several studies have explored consonance in nonhuman animals, so far with inclusive and sometimes perplexing results (54)(55)(56)(57)(58). For example, male hermit thrush songs comprise tones with harmonically related fundamental frequencies, despite the fact that their vocalizations do not exhibit strong harmonics (58).…”

Section: Some Caveatsmentioning

confidence: 99%

A biological rationale for musical consonance

Bowling

Purves

2015

114

128

The basis of musical consonance has been debated for centuries without resolution. Three interpretations have been considered: (i) that consonance derives from the mathematical simplicity of small integer ratios; (ii) that consonance derives from the physical absence of interference between harmonic spectra; and (iii) that consonance derives from the advantages of recognizing biological vocalization and human vocalization in particular. Whereas the mathematical and physical explanations are at odds with the evidence that has now accumulated, biology provides a plausible explanation for this central issue in music and audition.consonance | biology | music | audition | vocalization

“…Although their perception is in some cases dependent on context (4), marked differences between consonance and dissonance are typically apparent even in isolated chords (5)(6)(7)(8). Preferences for consonance appear to be present in human infants (9)(10)(11)(12) and perhaps also in other species with little exposure to music (13,14, although see also ref. 15), consistent with a biological basis.…”

mentioning

confidence: 99%

The basis of musical consonance as revealed by congenital amusia

Cousineau

McDermott

Peretz

2012

108

164

Some combinations of musical notes sound pleasing and are termed "consonant," but others sound unpleasant and are termed "dissonant." The distinction between consonance and dissonance plays a central role in Western music, and its origins have posed one of the oldest and most debated problems in perception. In modern times, dissonance has been widely believed to be the product of "beating": interference between frequency components in the cochlea that has been believed to be more pronounced in dissonant than consonant sounds. However, harmonic frequency relations, a higher-order sound attribute closely related to pitch perception, has also been proposed to account for consonance. To tease apart theories of musical consonance, we tested sound preferences in individuals with congenital amusia, a neurogenetic disorder characterized by abnormal pitch perception. We assessed amusics' preferences for musical chords as well as for the isolated acoustic properties of beating and harmonicity. In contrast to control subjects, amusic listeners showed no preference for consonance, rating the pleasantness of consonant chords no higher than that of dissonant chords. Amusics also failed to exhibit the normally observed preference for harmonic over inharmonic tones, nor could they discriminate such tones from each other. Despite these abnormalities, amusics exhibited normal preferences and discrimination for stimuli with and without beating. This dissociation indicates that, contrary to classic theories, beating is unlikely to underlie consonance. Our results instead suggest the need to integrate harmonicity as a foundation of music preferences, and illustrate how amusia may be used to investigate normal auditory function. music perception | aesthetic preferences | roughness