Laura K. Cirelli

Fourteen-month-old infants use interpersonal synchrony as a cue to direct helpfulness

Musical behaviours such as dancing, singing and music production, which require the ability to entrain to a rhythmic beat, encourage high levels of interpersonal coordination. Such coordination has been associated with increased group cohesion and social bonding between group members. Previously, we demonstrated that this association influences even the social behaviour of 14-month-old infants. Infants were significantly more likely to display helpfulness towards an adult experimenter following synchronous bouncing compared with asynchronous bouncing to music. The present experiment was designed to determine whether interpersonal synchrony acts as a cue for 14-month-olds to direct their prosocial behaviours to specific individuals with whom they have experienced synchronous movement, or whether it acts as a social prime, increasing prosocial behaviour in general. Consistent with the previous results, infants were significantly more likely to help an experimenter following synchronous versus asynchronous movement with this person. Furthermore, this manipulation did not affect infants behaviour towards a neutral stranger, who was not involved in any movement experience. This indicates that synchronous bouncing acts as a social cue for directing prosociality. These results have implications for how musical engagement and rhythmic synchrony affect social behaviour very early in development.

Beat-induced fluctuations in auditory cortical beta-band activity: using EEG to measure age-related changes.

People readily extract regularity in rhythmic auditory patterns, enabling prediction of the onset of the next beat. Recent magnetoencephalography (MEG) research suggests that such prediction is reflected by the entrainment of oscillatory networks in the brain to the tempo of the sequence. In particular, induced beta-band oscillatory activity from auditory cortex decreases after each beat onset and rebounds prior to the onset of the next beat across tempi in a predictive manner. The objective of the present study was to examine the development of such oscillatory activity by comparing electroencephalography (EEG) measures of beta-band fluctuations in 7-year-old children to adults. EEG was recorded while participants listened passively to isochronous tone sequences at three tempi (390, 585, and 780 ms for onset-to-onset interval). In adults, induced power in the high beta-band (20–25 Hz) decreased after each tone onset and rebounded prior to the onset of the next tone across tempo conditions, consistent with MEG findings. In children, a similar pattern was measured in the two slower tempo conditions, but was weaker in the fastest condition. The results indicate that the beta-band timing network works similarly in children, although there are age-related changes in consistency and the tempo range over which it operates.

Rhythm and interpersonal synchrony in early social development.

Adults who engage in synchronous movement to music later report liking each other better, remembering more about each other, trusting each other more, and are more likely to cooperate with each other compared to adults who engage in asynchronous movements. Although poor motor coordination limits infants’ ability to entrain to a musical beat, they perceive metrical structure in auditory rhythm patterns, their movements are affected by the tempo of music they hear, and if they are bounced by an adult to a rhythm pattern, the manner of this bouncing can affect their auditory interpretation of the meter of that pattern. In this paper, we review studies showing that by 14 months of age, infants who are bounced in synchrony with an adult subsequently show more altruistic behavior toward that adult in the form of handing back objects “accidentally” dropped by the adult compared to infants who are bounced asynchronously with the adult. Furthermore, increased helpfulness is directed at the synchronized bounce partner, but not at a neutral stranger. Interestingly, however, helpfulness does generalize to a “friend” of the synchronized bounce partner. In sum, synchronous movement between infants and adults has a powerful effect on infants’ expression of directed prosocial behavior.

Infants help singers of familiar songs

Infants are highly selective in their help to unfamiliar individuals. For example, they offer more help to partners who move synchronously with them rather than asynchronously and to partners who interact with them in a “nice” rather than “mean” manner. Infant-directed song and speech may also encourage infant helping by signaling caregiver quality. In the present study, we investigated the effect of infant-directed song and recitation on 14-month-old infants’ subsequent helpfulness and proximity-seeking in relation to unfamiliar performers. During a 2.5-minute exposure phase, infants sat on their caregiver’s lap opposite an experimenter who sang “The Ants Go Marching” (song condition), recited the lyrics (recitation condition), or remained silent while parents read them a book (baseline condition). After the exposure phase, infants participated in a series of helping tasks that necessitated the return of objects dropped “accidentally”. Infants in the song and recitation conditions helped more than those in the baseline condition, but their helping of singers was moderated by song familiarity. Specifically, the extent of help directed to singers correlated positively with song familiarity. Singing (and to some extent, recitation) also encouraged infants to seek proximity with the experimenter. The findings indicate that rhythmic song and recitation by an unfamiliar adult foster infant affiliative behavior, but familiar songs may have special social importance.

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.

Infants’ use of interpersonal asynchrony as a signal for third-party affiliation:

Infants use social cues to form expectations about the social relationships of others. For example, they expect agents to approach helpful partners and avoid hindering partners. They expect individuals with shared food preferences to be affiliates and individuals with opposing food preferences to be nonaffiliates. Interpersonal synchrony and asynchrony are important signals that adults use to guide third-party understanding. Specifically, we expect synchronous partners to be higher in rapport than asynchronous partners. Here, using a within-subjects design, we investigated if 12- to 14-month-old infants (n = 62) also use interpersonal synchrony and/or asynchrony to make sense of third-party social relationships. A violation of expectations paradigm adapted from Liberman and colleagues was used. Infant looking time was recorded while watching videos of two women. The women moved either synchronously or asynchronously during familiarization trials, and subsequently interacted either in a friendly way (waving) or an unfriendly way (turning away) on test trials. Results revealed that infants expected asynchronous partners to be nonaffiliates but showed no significant expectation for synchronous partners. These results suggest that infants use interpersonal movement to understand their social world from as early as 12 months of age.

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.