Infant attention to rhythmic audiovisual synchrony is modulated by stimulus properties.

Musical interactions are a common and multimodal part of an infant's daily experiences. Infants hear their parents sing while watching their lips move and see their older siblings dance along to music playing over the radio. Here, we explore whether 8- to 12-month-old infants associate musical rhythms they hear with synchronous visual displays by tracking their dynamic visual attention to matched and mismatched displays. Visual attention was measured using eye-tracking while they attended to a screen displaying two videos of a finger tapping at different speeds. These videos were presented side by side while infants listened to an auditory rhythm (high or low pitch) synchronized with one of the two videos. Infants attended more to the low-pitch trials than to the high-pitch trials but did not display a preference for attending to the synchronous hand over the asynchronous hand within trials. Exploratory evidence, however, suggests that tempo, pitch, and rhythmic complexity interactively engage infants' visual attention to a tapping hand, especially when that hand is aligned with the auditory stimulus. For example, when the rhythm was complex and the auditory stimulus was low in pitch, infants attended to the fast hand more when it aligned with the auditory stream than to misaligned trials. These results suggest that the audiovisual integration in rhythmic non-speech contexts is influenced by stimulus properties.

Who is singing? Voice recognition from spoken versus sung speech.

Singing is socially important but constrains voice acoustics, potentially masking certain aspects of vocal identity. Little is known about how well listeners extract talker details from sung speech or identify talkers across the sung and spoken modalities. Here, listeners (n = 149) were trained to recognize sung or spoken voices and then tested on their identification of these voices in both modalities. Learning vocal identities was initially easier through speech than song. At test, cross-modality voice recognition was above chance, but weaker than within-modality recognition. We conclude that talker information is accessible in sung speech, despite acoustic constraints in song.

Musical groove shapes children's free dancing.

The drive to move to music is evident across a variety of contexts, from the simple urge to tap our toe to a song on the radio, to massive crowds dancing in time at a rock concert. Though seemingly effortless, beat synchronization is difficult to master and children are often poor beat synchronizers. Nevertheless, auditory-motor integration is fundamental for many daily processes, such as speech. A topic that has been relatively understudied concerns how stimulus properties affect young children's movement in responses to auditory stimuli. In the present study, we examined how musical groove (adult-rated desire to move) affected 3.0- to 6.9-year-old children's free dancing in the comfort of their home (n = 78). In the high groove conditions, children danced more and with more energy compared to the low groove conditions. Moreover, in the high groove condition, children's movement tempos corresponded better with the tempos of the music. Results point to early childhood sensitivity to the musical features that motivate adults to move to music. High groove music may therefore prove especially effective at facilitating early auditory-motor integration. A video abstract of this article can be viewed at https://youtu.be/vli0-6N12Ts.

A concert for babies: Attentional, affective, and motor responses in an infant audience.

Many of our most powerful musical experiences are shared with others, and researchers have increasingly investigated responses to music in group contexts. Though musical performances for infants are growing in popularity, most research on infants' responses to live music has focused on solitary caregiver-infant pairs. Here, we report infants' attentional, affective, and motor responses to live music as audience members. Two groups of caregiver-infant (6-18 months) pairs (50 total) watched a short musical performance with two song styles - lullaby and playsong. Caregivers were instructed to watch passively or interactively. The playsong captured more infant attention and, especially in the interactive condition, elicited more infant smiles. Notably, infant attention was more coordinated with their own caregiver than a random caregiver, and infants with no experience attending group musical events in the past were especially attentive to the performance. Infants were more likely to generate movements when parents remained still. Overall, infants' responses to live musical performance in an audience were influenced by song style, caregiver behavior, and their own musical histories. A video abstract of this article can be viewed at https://www.youtube.com/watch?v=q61qnDMW8dU. RESEARCH HIGHLIGHTS: Infants' responses to live musical performances are shaped by the music, by their caregivers, and by their own musical histories During a concert for babies, a playsong more effectively elicited infant attention and smiles than a lullaby, especially when caregivers were interactive Infant attention was more coordinated with their own caregiver than with other caregivers watching the same show.

Acoustic regularities in infant-directed speech and song across cultures.

When interacting with infants, humans often alter their speech and song in ways thought to support communication. Theories of human child-rearing, informed by data on vocal signalling across species, predict that such alterations should appear globally. Here, we show acoustic differences between infant-directed and adult-directed vocalizations across cultures. We collected 1,615 recordings of infant- and adult-directed speech and song produced by 410 people in 21 urban, rural and small-scale societies. Infant-directedness was reliably classified from acoustic features only, with acoustic profiles of infant-directedness differing across language and music but in consistent fashions. We then studied listener sensitivity to these acoustic features. We played the recordings to 51,065 people from 187 countries, recruited via an English-language website, who guessed whether each vocalization was infant-directed. Their intuitions were more accurate than chance, predictable in part by common sets of acoustic features and robust to the effects of linguistic relatedness between vocalizer and listener. These findings inform hypotheses of the psychological functions and evolution of human communication.

Tiny dancers: Effects of musical familiarity and tempo on children's free dancing.

Around the world, musical engagement frequently involves movement. Most adults easily clap or sway to a wide range of tempos, even without formal musical training. The link between movement and music emerges early-young infants move more rhythmically to music than speech, but do not reliably align their movements to the beat. Laboratory work encouraging specific motor patterns (e.g., drumming, tapping) demonstrates that toddlers and young children's movements are affected by music in a rudimentary way, such that they move faster to faster rhythms (tempo flexibility). In the present study, we developed and implemented a novel home recording method to investigate how musical familiarity and tempo affect children's naturalistic free-dance movements. Caregivers made home recordings of their children's responses to an experimenter-created playlist (N = 83, age range = 1.25 to 3.91 years, Mage = 2.39 years, SD = .74 years; 41 girls, 42 boys; 75% of household incomes > $90 000 CAD). Children listened to 1-min excerpts of their favorite music and unfamiliar, genre-matched music, each played at 90, 120, and 150 bpm (pitch constant; order randomized). Children moved faster to faster music and demonstrated tempo flexibility for both favorite and unfamiliar music. Favorite music encouraged more smiling across tempo conditions than unfamiliar music, as well as more dancing in the slowest tempo condition. Results demonstrate that young children's self-selected movements are affected by musical tempo and familiarity. We also demonstrate the usefulness of a naturalistic home recording method for assessing early auditory-motor integration. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

The song, not the singer: Infants prefer to listen to familiar songs, regardless of singer identity.

Parent's infant-directed vocalizations are highly dynamic and emotive compared to their adult-directed counterparts, and correspondingly, more effectively capture infants' attention. Infant-directed singing is a specific type of vocalization that is common throughout the world. Parents tend to sing a small handful of songs in a stereotyped way, and a number of recent studies have highlighted the significance of familiar songs in young children's social behaviors and evaluations. To date, no studies have examined whether infants' responses to familiar versus unfamiliar songs are modulated by singer identity (i.e., whether the singer is their own parent). In the present study, we investigated 9- to 12-month-old infants' (N = 29) behavioral and electrodermal responses to relatively familiar and unfamiliar songs sung by either their own mother or another infant's mother. Familiar songs recruited more attention and rhythmic movement, and lower electrodermal levels relative to unfamiliar songs. Moreover, these responses were robust regardless of whether the singer was their mother or a stranger, even when the stranger's rendition differed greatly from their mothers' in mean fundamental frequency and tempo. Results indicate that infants' interest in familiar songs is not limited to idiosyncratic characteristics of their parents' song renditions, and points to the potential for song as an effective early signifier of group membership.

Survey of the Home Music Environment of Children with Various Developmental Profiles.

Families with young children with and without developmental disabilities often create a musically rich home environment. Parent-child music engagement, like singing play songs, is associated with positive outcomes for children, parents, and their relationship. However, little is known about if the home music environment differs across diagnostic groups and if parent-child music engagement relates to parent-child affective attachment across families of diagnostically diverse children. Using an online questionnaire, the current study examined the home music environment of 340 families with young children with typical and atypical development. A variety of musical activities were common in all diagnostic groups. Diagnostic groups differed in active musical engagement, potentially relating to the differing phenotypes of various developmental disabilities. Parent-child music engagement was associated with parent-child affective attachment, even when controlling for relevant variables. Promoting musical engagement at home and through parent-child therapy may be an accessible way to support parent-child relationships.

A syncing feeling: reductions in physiological arousal in response to observed social synchrony.

Synchronized movements are often key elements in activities where social bonding and emotional connection are a shared goal, such as religious gatherings, sporting events, parties and weddings. Previous studies have shown that synchronous movements enhance prosocial attitudes and affiliative behaviors. Similarly, observers attribute more social closeness to people moving synchronously together than people moving asynchronously. The mechanisms by which synchrony modulates these attributions are not well understood. In the present study, we ask whether viewing synchronous activities influences physiological arousal as measured by skin conductance and whether group size impacts this effect. Undergraduates viewed a series of short videos depicting people moving either (1) in or out of synchrony with each other and (2) in a large or small group. Participants' skin conductance was measured. Change in skin conductance levels and response counts were attenuated while watching synchronous movement, but only in the large-group condition. Post-hoc analyses suggest that viewer enjoyment/interest in the large-group synchronous videos mediated this association for phasic skin conductance responses, but no evidence of mediation was found for tonic skin conductance levels. Results extend previous research on affiliative effects of first-person interpersonal synchrony and demonstrate that watching others moving synchronously has an attenuating effect on observers' physiological state.

Individual differences in musical ability are stable over time in childhood.

The development of human abilities stems from a complex interplay between genetic predispositions and environmental factors. Numerous studies have compared musicians with non-musicians on measures of musical and non-musical ability, frequently attributing musicians' superior performance to their training. By ignoring preexisting differences, however, this view assumes that taking music lessons is akin to random assignment. In the present longitudinal study, the musical ability of 5- to 10-year-olds was measured at Time 1 with a test of music perception and cognition. Five years later, at Time 2, the children took the same test and a second test designed for older listeners. The test-retest correlation for aggregate scores was remarkably high, r ≈ 0.7, and remained strong when confounding variables (age, cognitive abilities, personality) were held constant. At both time points, music training was associated with musical ability, but the association at Time 2 became nonsignificant when musical ability at Time 1 was held constant. Time 1 musical ability also predicted duration of subsequent music training. These data are consistent with results from genetic studies, which implicate genes in all aspects of musical behavior and achievement, and with meta-analyses, which indicate that transfer effects from music training are weak. In short, early musical abilities significantly predicted later abilities, demonstrating that individual differences are stable over time. We found no evidence, however, to suggest that music training predicted musical ability after accounting for prior ability. The results underscore the importance of considering preexisting abilities in any type of learning.

Shaping children's racial bias through interpersonal movement.

The early emergence of racial biases points to the urgent need to understand how interpersonal experiences might shape them. We examined whether interpersonal movement shapes racial biases among 4- to 6-year-old Chinese children who had no prior contact with Black people. In Experiment 1 (N = 134), children played a musical game, moving either in or out of synchrony with a Chinese or Black adult. In Experiment 2 (N = 30), children were merely exposed to a Black adult. Across the two experiments, we found that synchronous movement increased children's feeling of social closeness toward their movement partner to a greater extent than asynchronous movement regardless of the partner's race. After moving in or out of synchrony with the Chinese adult, synchrony selectively increased children's explicit positive pro-own-race bias. However, after moving in or out of synchrony with the Black adult, both movement styles reduced explicit anti-other-race bias. Experiment 2 ruled out mere exposure to an other-race person as a driving factor for these effects. Our results suggest that musical engagement may be a promising intervention for reducing negative intergroup biases.

Familiar songs reduce infant distress.

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).

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

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 and calm infants and playsongs to engage and excite infants. In this study, mothers repeatedly sang Twinkle, Twinkle, Little Star to their infants (n = 30 dyads), alternating between soothing and playful renditions. Infant attention and mother-infant arousal (i.e., skin conductivity) were recorded continuously. During soothing renditions, mother and infant arousal decreased below initial levels as the singing progressed. During playful renditions, maternal and infant arousal remained stable. Moreover, infants exhibited greater attention to mother during playful renditions than during soothing renditions. Mothers' playful renditions were faster, higher in pitch, louder, and characterized by greater pulse clarity than their soothing renditions. Mothers also produced more energetic rhythmic movements during their playful renditions. These findings highlight the contrastive nature and consequences of lullabies and playsongs.

Development of consonance preferences in Western listeners.

Many scholars consider preferences for consonance, as defined by Western music theorists, to be based primarily on biological factors, while others emphasize experiential factors, notably the nature of musical exposure. Cross-cultural experiments suggest that consonance preferences are shaped by musical experience, implying that preferences should emerge or become stronger over development for individuals in Western cultures. However, little is known about this developmental trajectory. We measured preferences for the consonance of simultaneous sounds and related acoustic properties in children and adults to characterize their developmental course and dependence on musical experience. In Study 1, adults and children 6 to 10 years of age rated their liking of simultaneous tone combinations (dyads) and affective vocalizations. Preferences for consonance increased with age and were predicted by changing preferences for harmonicity-the degree to which a sound's frequencies are multiples of a common fundamental frequency-but not by evaluations of beating-fluctuations in amplitude that occur when frequencies are close but not identical, producing the sensation of acoustic roughness. In Study 2, musically trained adults and 10-year-old children also rated the same stimuli. Age and musical training were associated with enhanced preference for consonance. Both measures of experience were associated with an enhanced preference for harmonicity, but were unrelated to evaluations of beating stimuli. The findings are consistent with cross-cultural evidence and the effects of musicianship in Western adults in linking Western musical experience to preferences for consonance and harmonicity. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Dancing to Metallica and Dora: Case Study of a 19-Month-Old.

Rhythmic movement to music, whether deliberate (e.g., dancing) or inadvertent (e.g., foot-tapping), is ubiquitous. Although parents commonly report that infants move rhythmically to music, especially to familiar music in familiar environments, there has been little systematic study of this behavior. As a preliminary exploration of infants' movement to music in their home environment, we studied V, an infant who began moving rhythmically to music at 6 months of age. Our primary goal was to generate testable hypotheses about movement to music in infancy. Across nine sessions, beginning when V was almost 19 months of age and ending 8 weeks later, she was video-recorded by her mother during the presentation of 60-s excerpts from two familiar and two unfamiliar songs presented at three tempos-the original song tempo as well as faster and slower versions. V exhibited a number of repeated dance movements such as head-bobbing, arm-pumping, torso twists, and bouncing. She danced most to Metallica's Now that We're Dead, a recording that her father played daily in V's presence, often dancing with her while it played. Its high pulse clarity, in conjunction with familiarity, may have increased V's propensity to dance, as reflected in lesser dancing to familiar music with low pulse clarity and to unfamiliar music with high pulse clarity. V moved faster to faster music but only for unfamiliar music, perhaps because arousal drove her movement to familiar music. Her movement to music was positively correlated with smiling, highlighting the pleasurable nature of the experience. Rhythmic movement to music may have enhanced her pleasure, and the joy of listening may have promoted her movement. On the basis of behavior observed in this case study, we propose a scaled-up study to obtain definitive evidence about the effects of song familiarity and specific musical features on infant rhythmic movement, the developmental trajectory of dance skills, and the typical range of variation in such skills.

Precursors to the performing arts in infancy and early childhood.

Across cultures, aspects of music and dance contribute to everyday life in a variety of ways that do not depend on artistry, aesthetics, or expertise. In this chapter, we focus on precursors to music and dance that are evident in infancy: the underlying perceptual abilities, parent-infant musical interactions that are motivated by nonmusical goals, the consequences of such interactions for mood regulation and social regulation, and the emergence of rudimentary singing and rhythmic movement to music. These precursors to music and dance lay the groundwork for our informal engagement with music throughout life and its continuing effects on mood regulation, affiliation, and well-being.

Rhythm and melody as social signals for infants.

Infants typically experience music through social interactions with others. One such experience involves caregivers singing to infants while holding and bouncing them rhythmically. These highly social interactions shape infant music perception and may also influence social cognition and behavior. Moving in time with others-interpersonal synchrony-can direct infants' social preferences and prosocial behavior. Infants also show social preferences and selective prosociality toward singers of familiar, socially learned melodies. Here, we discuss recent studies of the influence of musical engagement on infant social cognition and behavior, highlighting the importance of rhythmic movement and socially relevant melodies.

How interpersonal synchrony facilitates early prosocial behavior.

When infants and children affiliate with others, certain cues may direct their social efforts to 'better' social partners. Interpersonal synchrony, or when two or more people move together in time, can be one such cue. In adults, experiencing interpersonal synchrony encourages affiliative behaviors. Recent studies have found that these effects also influence early prosociality-for example, 14-month-olds help a synchronous partner more than an asynchronous partner. These effects on helping are specifically directed to the synchronous movement partner and members of that person's social group. In older children, the prosocial effects of interpersonal synchrony may even cross group divides. How synchrony and other cues for group membership influence early prosociality is a promising avenue for future research.

Children's and adults' perception of questions and statements from terminal fundamental frequency contours.

The present study compared children's and adults' identification and discrimination of declarative questions and statements on the basis of terminal cues alone. Children (8-11 years, n = 41) and adults (n = 21) judged utterances as statements or questions from sentences with natural statement and question endings and with manipulated endings that featured intermediate fundamental frequency (F0) values. The same adults and a different sample of children (n = 22) were also tested on their discrimination of the utterances. Children's judgments shifted more gradually across categories than those of adults, but their category boundaries were comparable. In the discrimination task, adults found cross-boundary comparisons more salient than within-boundary comparisons. Adults' performance on the identification and discrimination tasks is consistent with but not definitive regarding categorical perception of statements and questions. Children, by contrast, discriminated the cross-boundary comparisons no better than other comparisons. The findings indicate age-related sharpening in the perception of statements and questions based on terminal F0 cues and the gradual emergence of distinct perceptual categories.

Measuring Neural Entrainment to Beat and Meter in Infants: Effects of Music Background.

Caregivers often engage in musical interactions with their infants. For example, parents across cultures sing lullabies and playsongs to their infants from birth. Behavioral studies indicate that infants not only extract beat information, but also group these beats into metrical hierarchies by as early as 6 months of age. However, it is not known how this is accomplished in the infant brain. An EEG frequency-tagging approach has been used successfully with adults to measure neural entrainment to auditory rhythms. The current study is the first to use this technique with infants in order to investigate how infants' brains encode rhythms. Furthermore, we examine how infant and parent music background is associated with individual differences in rhythm encoding. In Experiment 1, EEG was recorded while 7-month-old infants listened to an ambiguous rhythmic pattern that could be perceived to be in two different meters. In Experiment 2, EEG was recorded while 15-month-old infants listened to a rhythmic pattern with an unambiguous meter. In both age groups, information about music background (parent music training, infant music classes, hours of music listening) was collected. Both age groups showed clear EEG responses frequency-locked to the rhythms, at frequencies corresponding to both beat and meter. For the younger infants (Experiment 1), the amplitudes at duple meter frequencies were selectively enhanced for infants enrolled in music classes compared to those who had not engaged in such classes. For the older infants (Experiment 2), amplitudes at beat and meter frequencies were larger for infants with musically-trained compared to musically-untrained parents. These results suggest that the frequency-tagging method is sensitive to individual differences in beat and meter processing in infancy and could be used to track developmental changes.