Rate of infant carrying impacts infant spontaneous motor tempo

Which factors modulate spontaneous motor tempo? A systematic review of the literature

Intentionally or not, humans produce rhythmic behaviors (e.g., walking, speaking, and clapping). In 1974, Paul Fraisse defined rhythmic behavior as a periodic movement that obeys a temporal program specific to the subject and that depends less on the conditions of the action (p. 47). Among spontaneous rhythms, the spontaneous motor tempo (SMT) corresponds to the tempo at which someone produces movements in the absence of external stimuli, at the most regular, natural, and pleasant rhythm for him/her. However, intra- and inter-individual differences exist in the SMT values. Even if several factors have been suggested to influence the SMT (e.g., the age of participants), we do not yet know which factors actually modulate the value of the SMT. In this context, the objectives of the present systematic review are (1) to characterize the range of SMT values found in the literature in healthy human adults and (2) to identify all the factors modulating the SMT values in humans. Our results highlight that (1) the reference value of SMT is far from being a common value of 600 ms in healthy human adults, but a range of SMT values exists, and (2) many factors modulate the SMT values. We discuss our results in terms of intrinsic factors (in relation to personal characteristics) and extrinsic factors (in relation to environmental characteristics). Recommendations are proposed to assess the SMT in future research and in rehabilitative, educative, and sport interventions involving rhythmic behaviors.

Early social communication through music: State of the art and future perspectives

A growing body of research shows that the universal capacity for music perception and production emerges early in development. Possibly building on this predisposition, caregivers around the world often communicate with infants using songs or speech entailing song-like characteristics. This suggests that music might be one of the earliest developing and most accessible forms of interpersonal communication, providing a platform for studying early communicative behavior. However, little research has examined music in truly communicative contexts. The current work aims to facilitate the development of experimental approaches that rely on dynamic and naturalistic social interactions. We first review two longstanding lines of research that examine musical interactions by focusing either on the caregiver or the infant. These include defining the acoustic and non-acoustic features that characterize infant-directed (ID) music, as well as behavioral and neurophysiological research examining infants' processing of musical timing and pitch. Next, we review recent studies looking at early musical interactions holistically. This research focuses on how caregivers and infants interact using music to achieve co-regulation, mutual engagement, and increase affiliation and prosocial behavior. We conclude by discussing methodological, technological, and analytical advances that might empower a comprehensive study of musical communication in early childhood.

Scoping Review of Biological and Behavioral Effects of Babywearing on Mothers and Infants

OBJECTIVE

To synthesize the evidence on the biological and behavioral effects of babywearing on mothers and infants.

DATA SOURCES

We searched PubMed, CINAHL, Embase, PsycINFO, Sociological Abstracts, SCOPUS, and Google Scholar for peer-reviewed, full-text research articles published in English in which researchers reported on the biological or behavioral effects of babywearing on mothers or infants.

STUDY SELECTION

We reviewed the titles and abstracts of 200 records and abstracted 80 for full-text review. Of these, 29 studies met the eligibility criteria and were included in the review.

DATA EXTRACTION

We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) and extracted the following data from the included articles: author(s), year of publication, setting, aim/purpose, design, description, sample, results/outcomes, and implications to practice.

DATA SYNTHESIS

We synthesized data from the included studies into the following eight themes: Increased Contact, Responsiveness, and Secure Attachment; Physiologic Effects; Biomechanics and Positioning; Facilitating and Empowering; Comfort; Maternal Benefits; Speech, Vocalizations, and Tempo; and Beliefs and Perceptions About Babywearing.

CONCLUSION

Babywearing may have a range of beneficial biological and behavioral effects on mothers and infants. The evidence, however, is insufficient to inform practice recommendations, and additional research is warranted.