Why do humans make music? Theories of the evolution of musicality have focused mainly on the value of music for specific adaptive contexts such as mate selection, parental care, coalition signaling, and group cohesion. Synthesizing and extending previous proposals, we argue that social bonding is an overarching function that unifies all of these theories, and that musicality enabled social bonding at larger scales than grooming and other bonding mechanisms available in ancestral primate societies. We combine cross-disciplinary evidence from archeology, anthropology, biology, musicology, psychology, and neuroscience into a unified framework that accounts for the biological and cultural evolution of music. We argue that the evolution of musicality involves gene-culture coevolution, through which proto-musical behaviors that initially arose and spread as cultural inventions had feedback effects on biological evolution because of their impact on social bonding. We emphasize the deep links between production, perception, prediction, and social reward arising from repetition, synchronization, and harmonization of rhythms and pitches, and summarize empirical evidence for these links at the levels of brain networks, physiological mechanisms, and behaviors across cultures and across species. Finally, we address potential criticisms and make testable predictions for future research, including neurobiological bases of musicality and relationships between human music, language, animal song, and other domains. The music and social bonding hypothesis provides the most comprehensive theory to date of the biological and cultural evolution of music.

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Music as a coevolved system for social bonding

Parents commonly vocalize to infants to mitigate their distress, especially when holding them is not possible. Here we examined the relative efficacy of parents' speech and singing (familiar and unfamiliar songs) in alleviating the distress of 8- and 10-month-old infants (n = 68 per age group). Parent-infant dyads participated in 3 trials of the Still Face procedure, featuring a 2-min Play Phase, a Still Face phase (parents immobile and unresponsive for 1 min or until infants became visibly distressed), and a 2-min Reunion Phase in which caregivers attempted to reverse infant distress by (a) singing a highly familiar song, (b) singing an unfamiliar song, or (c) expressive talking (order counterbalanced across dyads). In the Reunion Phase, talking led to increased negative affect in both age groups, in contrast to singing familiar or unfamiliar songs, which increased infant attention to parent and decreased negative affect. The favorable consequences were greatest for familiar songs, which also generated increased smiling. Skin conductance recorded from a subset of infants (n = 36 younger, 41 older infants) revealed that arousal levels were highest for the talking reunion, lowest for unfamiliar songs, and intermediate for familiar songs. The arousal effects, considered in conjunction with the behavioral effects, confirm that songs are more effective than speech at mitigating infant distress. We suggest, moreover, that familiar songs generate higher infant arousal than unfamiliar songs because they evoke excitement, reflected in modestly elevated arousal as well as pleasure, in contrast to more subdued responses to unfamiliar songs. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

/pdf/familiar-songs-reduce-infant-distress-18qakbzzo3.pdf

Familiar songs reduce infant distress

Social interactions are essential for understanding others’ actions and their mental and affective states. Specifically, interpersonal coordination – also referred to as synchrony – allows actors to adjust their behaviors to one another and thus demonstrate their connectedness to each other. Much behavioral research has demonstrated the primacy of mutually synchronized social exchanges in early development. Additionally, new methodological advances now allow us to examine interpersonal synchrony not only at the behavioral and physiological, but also neural level. Nevertheless, it remains unclear how infants and their caregivers actually achieve interpersonal synchrony in their exchanges. Here we discuss recent evidence showing that adults provide rhythmical information during early social interactions with their infants, such as affective touch and singing. We propose that entrainment to these social rhythms underlies the formation of interpersonal synchrony and thus stimulates reciprocal interactions between infants and their caregivers.

/pdf/neurobehavioral-interpersonal-synchrony-in-early-development-5e993vsc4z.pdf

Neurobehavioral Interpersonal Synchrony in Early Development: The Role of Interactional Rhythms.

Music is characterized by acoustic forms that are predictive of its behavioural functions. For example, adult listeners accurately identify unfamiliar lullabies as infant-directed on the basis of their musical features alone. This property could reflect a function of listeners’ experiences, the basic design of the human mind, or both. Here, we show that US infants (N = 144) relax in response to eight unfamiliar foreign lullabies, relative to matched non-lullaby songs from other foreign societies, as indexed by heart rate, pupillometry and electrodermal activity. They do so consistently throughout the first year of life, suggesting that the response is not a function of their musical experiences, which are limited relative to those of adults. The infants’ parents overwhelmingly chose lullabies as the songs that they would use to calm their fussy infant, despite their unfamiliarity. Together, these findings suggest that infants may be predisposed to respond to common features of lullabies found in different cultures. Infants listened to lullabies and other songs recorded in cultures and languages that were unfamiliar to them. They relaxed more in response to the lullabies. This suggests that infants may be predisposed to respond to common features of lullabies.

Infants relax in response to unfamiliar foreign lullabies

Music frequently elicits intense emotional responses, a phenomenon that has been scrutinized from multiple disciplines that span the sciences and arts. While most people enjoy music and find it rewarding, there is substantial individual variability in the experience and degree of music-induced reward. Here, we review current work on the neural substrates of hedonic responses to music. In particular, we focus the present review on specific musical anhedonia, a selective lack of pleasure from music. Based on evidence from neuroimaging, neuropsychology, and brain stimulation studies, we derive a neuroanatomical model of the experience of pleasure during music listening. Our model posits that hedonic responses to music are the result of connectivity between structures involved in auditory perception as a predictive process, and those involved in the brain's dopaminergic reward system. We conclude with open questions and implications of this model for future research on why humans appreciate music.

Musical anhedonia and rewards of music listening: current advances and a proposed model

Mothers around the world sing to infants, presumably to regulate their mood and arousal. Lullabies and playsongs differ stylistically and have distinctive goals. Mothers sing lullabies to soothe an...

Zuzanna B. Jurewicz

Papers

Effects of Maternal Singing Style on Mother-Infant Arousal and Behavior.