An upcoming issue of Behavioral and Brain Sciences contains two target articles discussing the origins of musicality. Sam Mehr and colleagues argue that musicality originates in credible signaling, while Pat Savage and colleagues instead point to social bonding.
We asked the many commentators where they would position themselves in this debate. Click on the points below to find out!
The two target articles address the origins of music in complementary ways. However, both proposals focus on overt musical behaviour, largely ignoring the role of perception and cognition, and they blur the boundaries between the potential origins of language and music. To resolve this, an alternative research strategy is proposed that focuses on the core cognitive components of musicality.
Luke Rendell, Emily L. Doolittle, Ellen C. Garland & Alex South
Focus on the evolutionary origins of musicality has been neglected relative to attention on language, so these new proposals are welcome stimulants. We argue for a broad comparative approach to understanding how the elements of musicality evolved, and against the use of overly simplistic evolutionary accounts.
Edgar Dubourg, Jean-Baptiste André & Nicolas Baumard
We propose an approach reconciling the ultimate-level explanations proposed by Savage et al. and Mehr et al. as to why music evolved. We also question the current adaptationist view of culture, which too often fails to disentangle distinct fitness benefits.
Based on their social bonding hypothesis, Savage et al. predict a relation between “musical” behaviors and social complexity across species. However, our qualitative comparative review suggests that, although learned contact calls are positively associated with complex social dynamics across species, songs are not. Yet, in contrast to songs, and arguably consistent with their functions, contact calls are not particularly music-like.
Caitlyn Trevor & Sascha Frühholz
The credible signaling theory underexplains the evolutionary added value of less-credible affective musical signals compared to vocal signals. The theory might be extended to account for the motivation for, and consequences of, culturally decontextualizing a biologically contextualized signal. Musical signals are twofold, communicating “emotional fiction” alongside biological meaning, and could have filled an adaptive need for affect induction during storytelling.
The music and social bonding (MSB) hypothesis suggests that damage to brain regions in the proposed neurobiological model, including the ventromedial prefrontal cortex (vmPFC), would disrupt the social and emotional effects of music. This commentary evaluates prior research in persons with vmPFC damage in light of the predictions put forth by the MSB hypothesis.
I propose an adjunct to the two models presented in the target articles, a function of music that is ubiquitous and would have solved a clear adaptive problem, that of transmitting important survival information among pre-literate humans. This class of knowledge songs uniquely preserved cultural, botanical, medical, safety, and practical information that increased the adaptive fitness of societies.
The music learning environment is a context in which fundamental forces and values underlying human musicality may be evident. Social bonding within music-making groups is characterized by a high degree of complexity whereas issues of clarity, accuracy, and coordination remain the focus of learning. Physical and cognitive impairments that compromise music learning opportunities offer a critical test of music's link to social bonding.
Savage et al. propose that music filled a hypothetical “bonding gap” in human sociality by Baldwinian gene-culture coevolution (or protracted cognitive niche construction). Both these stepping stones to an evolutionary account of the function and origin of music are problematic. They are scrutinized in this commentary, and an alternative is proposed.
Parker Tichko, Kevin A. Bird & Gregory Kohn
In their article, Mehr et al. conclude that the design features of music are consistent with adaptations for credible signaling. Although appealing to design may seem like a plausible basis for identifying adaptations, probing adaptive theories of music must be done at the genomic level and will require a functional understanding of the genomic, phenotypic, and fitness properties of music.
We propose that not social bonding, but rather a different mechanism underlies the development of musicality: being unable to survive alone. The evolutionary constraint of being dependent on other humans for survival provides the ultimate driving force for acquiring human faculties such as sociality and musicality, through mechanisms of learning and neural plasticity. This evolutionary mechanism maximizes adaptation to a dynamic environment.
Erin E. Hannon, Alyssa N. Crittenden, Joel S. Snyder & Karli M. Nave
Both target papers cite evidence from infancy and early childhood to support the notion of human musicality as a somewhat static suite of capacities; however, in our view they do not adequately acknowledge the critical role of developmental timing, the acquisition process, or the dynamics of social learning, especially during later periods of development such as middle childhood.
Both Mehr et al.'s credible signaling hypothesis and Savage et al.'s music and social bonding hypothesis emphasize the role of multilevel social structures in the evolution of music. Although empirical evidence preferentially supports the social bonding hypothesis, rhythmic music may enable bonding in a way uniquely fitted to the normative and language-based character of multilevel human societies.
Daniel L. Bowling, Marisa Hoeschele & Jacob C. Dunn
Mehr et al.'s hypothesis that the origins of music lie in credible signaling emerges here as a strong contender to explain early adaptive functions of music. Its integration with evolutionary biology and its specificity mark important contributions. However, much of the paper is dedicated to the exclusion of popular alternative hypotheses, which we argue is unjustified and premature.
Mehr et al. propose a theory of the evolution music that can potentially account for most animal vocalizations as precursors to human music. Therein lies its appeal but also its Achilles' heel, for the wider the range of animal vocalizations treated as premusical expressions, the wider the gap to human music. Here, I offer a few critical observations and constructive suggestions that I hope will help the authors strengthen their case.
I challenge Mehr et al.'s contention that ancestral mothers were reluctant to provide all the attention demanded by their infants. The societies in which music emerged likely involved foraging mothers who engaged in extensive infant carrying, feeding, and soothing. Accordingly, their singing was multimodal, its rhythms aligned with maternal movements, with arousal regulatory consequences for singers and listeners.
Both of the companion target articles place considerable performance on music performance ability, with specific attention paid to singing in harmony for the music and social bonding (MSB) hypothesis proposed by Savage and colleagues. In this commentary, I evaluate results from recent research on singing accuracy in light of their implications for the MSB hypothesis.
Cody Moser, Jordan Ackerman, Alex Dayer, Shannon Proksch & Paul E. Smaldino
We suggest that the accounts offered by the target articles could be strengthened by acknowledging the role of group selection and cultural niche construction in shaping the evolutionary trajectory of human music. We argue that group level traits and highly variable cultural niches can explain the diversity of human song, but the target articles' accounts are insufficient to explain such diversity.
Melanie Wald-Fuhrmann, Lara Pearson, Tina Roeske, Christian Grüny & Rainer Polak
Although it can be straightforward to define the features of physical traits, complex cultural categories tend to elude widely accepted definitions that transcend cultural and historical context. Addressing papers by Mehr et al. and Savage et al., which both aim to explain music as an evolved trait, we discuss fundamental problems that arise from their conceptualizations of music.
Human infants are born ready to respond to affiliative signals of a caretaker's face, body, and voice. This ritualized behavior in ancestral mothers and infants was an adaptation that gave rise to music and dance as exaptations for promoting group ritual and other social bonding behaviors, arguing for an evolutionary relationship between mother and infant bonding and both music and dance.
Comparative studies of primates indicate that humans have evolved unique motivations and cognitive skills for sharing emotions, experiences, and collaborative actions. Given the characteristics of music, the music and social bonding (MSB) hypothesis by Savage et al. fits this view. Within a cross-species approach, predispositions not observed in current communication system may contribute to a better understanding of the biological roots of human musicality.
Both the music and social bonding (MSB) hypothesis and the music as a credible signal hypothesis emerge as solid views of how human music and human musicality might have evolved. Nonetheless, both views could be improved (and tested in better ways) with the consideration of the way in which human language(s) might have evolved under the effects of our self-domestication.
Thom Scott-Phillips, Atsuko Tominaga & Helena Miton
The two target articles agree that processes of cultural evolution generate richness and diversity in music, but neither address this question in a focused way. We sketch one way to proceed – and hence suggest how the target articles differ not only in empirical claims, but also in their tacit, prior assumptions about the relationship between cognition and culture.
Dustin Eirdosh & Susan Hanisch
Is musicality an individual level adaptation? The authors of this target article reject the need for group selection within their model, yet their arguments do not fulfill the conceptual requirements for justifying such a rejection. Further analysis can highlight the explanatory value of embracing multilevel selection theory as a foundational element of the music and social bonding (MSB) hypothesis.
Savage et al. include groove and dance among musical features which enhance social bonds and group coherence. I discuss groove as grounded in structure and performance, and relate musical performance to play in nonhuman animals and humans. The interplay of individuals' contributions with group action is proposed as the common link between music and play as contributors to social bonding.
Niels Chr. Hansen & Peter E. Keller
Despite acknowledging that musicality evolved to serve multiple adaptive functions in human evolution, Savage et al. promote social bonding to an overarching super-function. Yet, no unifying neurobiological framework is offered. We propose that oxytocin constitutes a socio-allostatic agent whose modulation of sensing, learning, prediction, and behavioral responses with reference to the physical and social environment facilitates music's social bonding effects.
Anna Kasdan, Reyna L. Gordon & Miriam D. Lense
Our commentary addresses how two neurodevelopmental disorders, Williams syndrome and autism spectrum disorder, provide novel insights into the credible signaling and music and social bonding hypotheses presented in the two target articles. We suggest that these neurodevelopmental disorders, characterized by atypical social communication, allow us to test hypotheses about music, social bonding, and their underlying neurobiology.
Savage et al. argue for musicality as having evolved for the overarching purpose of social bonding. By way of contrast, we highlight contemporary predictive processing models of human cognitive functioning in which the production and enjoyment of music follows directly from the principle of prediction error minimization.
Tudor Popescu, Nathan Oesch & Bryony Buck
Savage et al. make a compelling case, Mehr et al. less so, for social bonding and credible signalling, respectively, as the main adaptive function of human musicality. We express general advocacy for the former thesis, highlighting: (1) overlap between the two; (2) direct versus derived biological functions, and (3) aspects of music embedded in cultural evolution, for example, departures from tonality.
Peter M. C. Harrison & Madeleine Seale
Savage et al. and Mehr et al. provide well-substantiated arguments that the evolution of musicality was shaped by adaptive functions of social bonding and credible signalling. However, they are too quick to dismiss byproduct explanations of music evolution, and to present their theories as complete unitary accounts of the phenomenon.
The category “music” as used in this area of science is inconsistent and unstable, and its logical relationship to the word “musicality” – used by scientists to denote the human capacity for music – is circular. Therefore, rather than pursue the question, “Why did music(ality) evolve?” let us ask more inclusively, “What experiences in humankind's deep past might have felt like music?”
By fostering bonding (Mehr et al.; Savage et al.), music illustrates marvelously its ability to induce emotional experience. But, music can induce emotion more generally as well. To help explain how music fosters bonding and induces other emotions, I propose that music derives this power from the evolution of what I term “gestural messaging.”
Matthew E. Sachs, Oriel FeldmanHall & Diana I. Tamir
To corroborate the music and social bonding hypothesis, we propose that future investigations isolate specific components of social bonding and consider the influence of context. We deconstruct and operationalize social bonding through the lens of social psychology and provide examples of specific measures that can be used to assess how the link between music and sociality varies by context.
Music is an artistic cultural innovation, and therefore it may be considered as intuitive thought expressed in symbols, which can efficiently convey multiple meanings in learning, thinking, and transmission, selected for and passed on through cultural evolution. The symbolic system has personal adaptive benefits besides social ones, which should not be overlooked even if music may tend more to the latter.
Aniruddh D. Patel & Chris von Rueden
Collective, synchronous music-making is far from ubiquitous across traditional, small-scale societies. We describe societies that lack collective music and offer hypotheses to help explain this cultural variation. Without identifying the factors that explain variation in collective music-making across these societies, theories of music evolution based on social bonding (Savage et al.) or coalition signaling (Mehr et al.) remain incomplete.
The view of music as a byproduct of other cognitive functions has been deemed incomplete or incorrect. Revisiting the six lines of evidence that support this conclusion, it is argued that it is unclear how the hypothesis that music has its origins in (musi)language is discarded. Two additional promising research lines that can support or discard the byproduct hypothesis are presented.
Ivan Yifan Zou & William S.-Y. Wang
We extend Savage et al.'s music and social bonding hypothesis by examining it in the context of Chinese music. First, top-down functions such as music as political instrument should receive more attention. Second, solo performance can serve as important cues for social identity. Third, a right match between the tones in lyrics and music contributes also to social bonding.
Both papers – to different degrees – underplay the interactive dimensions of music, and both would have benefited from integrating the concept of attachment into their treatments of social bonding. I further suggest that their treatment of music as a discrete domain of human experience and behaviour weakens their arguments concerning its functions in human evolution.
A cross-species perspective can extend and provide testable predictions for Savage et al.'s framework. Rhythm and melody, I argue, could bootstrap each other in the evolution of musicality. Isochrony may function as a temporal grid to support rehearsing and learning modulated, pitched vocalizations. Once this melodic plasticity is acquired, focus can shift back to refining rhythm processing and beat induction.
Savage et al. do an excellent job of making the case for social bonding in general, but do a less good job of distinguishing the manners by which dance and music achieve this. It is important to see dance and music as two parallel and interactive mechanisms that employ the “group body” and “group voice,” respectively, in engendering social cohesion.
Courtney B. Hilton, Rie Asano & Cedric Boeckx
Credible signaling may have provided a selection pressure for producing and discriminating increasingly elaborate proto-musical signals. But, why evolve them to have hierarchical structure? We argue that the hierarchality of tonality and meter is a byproduct of domain-general mechanisms evolved for reasons other than credible signaling.
Massimo Lumaca, Elvira Brattico & Giosuè Baggio
The argument by Mehr et al. that music emerged and evolved culturally as a credible signal is convincing, but it lacks one essential ingredient: a model of signaling behavior that supports the main hypothesis theoretically and empirically. We argue that signaling games can help us explain how musical structures emerge as population-level phenomena, through sender–receiver signaling interactions.
The evolutionary origins of complex capacities such as musicality are not simple, and likely involved many interacting steps of musicality-specific adaptations, exaptations, and cultural creation. A full account of the origins of musicality needs to consider the role of ancient adaptations such as credible singing, auditory scene analysis, and prediction-reward circuits in constraining the emergence of musicality.
Music's efficacy as a credible signal and/or as a tool for social bonding piggybacks on a diverse set of biological and cognitive processes, implying different proximate mechanisms. It is likely this multiplicity of mechanisms that explains why it is so difficult to account for music's putative biological role(s), as well as its possible origins, by proposing a single adaptive function.
Kate T. Snyder & Nicole Creanza
Here, we compare birdsong and human musicality using insights from songbird neuroethology and evolution. For example, neural recordings during songbird duetting and other coordinated vocal behaviors could inform mechanistic hypotheses regarding human brain function during music-making. Furthermore, considering songbird evolution as a model system suggests that selection favoring certain culturally transmitted behaviors can indirectly select for associated underlying neural functions.
Jessica A. Grahn, Anna-Katharina R. Bauer & Anna Zamm
Music uses the evolutionarily unique temporal sensitivity of the auditory system and its tight coupling to the motor system to create a common neurophysiological clock between individuals that facilitates action coordination. We propose that this shared common clock arises from entrainment to musical rhythms, the process by which partners' brains and bodies become temporally aligned to the same rhythmic pulse.
This article is extraordinarily rigorous and rich, although there are reasons to be skeptical of its theory that music originated to signal group quality and infant solicitude. These include the lack of any signature of the centrality of these functions in the distribution or experience of music; of a role for the pleasure taken in music; and of its connections with language.
“Music As a Coevolved System for Social Bonding” (MSB) is a brilliant synthesis and appealing hypothesis offering insights into the evolution and social bonding of musicality, but is so broad and sweeping it will be challenging to test, prove or falsify in the Popperian sense (Popper, 1959). After general comments, I focus my critique on underlying neurobiological mechanisms, and offer some suggestions for experimental tests of MSB.
Miriam Akkermann, Ugur Can Akkaya, Cagatay Demirel, Dirk Pflüger & Martin Dresler
Music is part of the cultural practice and, at the same time, is interwoven with biology through its effects on the brain and its likely evolutionary origin. Studies on music, however, are traditionally based on the humanities and often carried out in a purely historical context, without much input from neuroscience and biology. Here, we argue that lullabies are a particularly suited test case to study the biological versus cultural aspects of music.
A project by Henkjan Honing and Bas Cornelissen
Data and code available on GitHub