Music therapy is increasingly being used as an intervention for stress reduction in both medical and mental healthcare settings. Music therapy is characterized by personally tailored music interventions initiated by a trained and qualified music therapist, which distinguishes music therapy from other music interventions, such as 'music medicine', which concerns mainly music listening interventions offered by healthcare professionals. To summarize the growing body of empirical research on music therapy, a multilevel meta-analysis, containing 47 studies, 76 effect sizes and 2.747 participants, was performed to assess the strength of the effects of music therapy on both physiological and psychological stress-related outcomes, and to test potential moderators of the intervention effects. Results showed that music therapy showed an overall medium-to-large effect on stress-related outcomes (d = .723, [.51-.94]). Larger effects were found for clinical controlled trials (CCT) compared to randomized controlled trials (RCT), waiting list controls instead of care as usual (CAU) or other stress-reducing interventions, and for studies conducted in Non-Western countries compared to Western countries. Implications for both music therapy and future research are discussed.

Personal norms consist of individuals’ attitudes about the appropriateness of behaviour. These norms guide adolescents’ behaviour in countless domains that are fundamental for their social functioning and well-being. Peers are known to have a marked influence on adolescent risk-taking and prosocial behaviour, but little is known about how peers shape personal norms underlying those behaviours. Here we show that adolescents’ personal norms are decisively moulded by the norms of the majority and popular peers in their social network. Our experiment indicates that observing peer norms substantially impacts adolescents’ normative evaluation of risk-taking and prosocial behaviours. The majority norm had a stronger impact than the norm of a single popular peer, and norm adjustments were largest when adolescents observed strong disapproval of risk-taking or strong approval of prosocial behaviour. Our study suggests that learning about peer norms likely promotes adolescents to hold views and values supporting socially desirable behaviour.

Social learning can help individuals to efficiently acquire knowledge and skills. In the classroom, social learning often takes place in structured settings in which peers help, support, and tutor each other. Several protocols have been developed to make peer-assisted learning (PAL) more efficient. However, little attention has been devoted to how the transfer of knowledge is shaped by the social relationship between peers, and their relative positions in the social network. To address this gap, we combined social network analysis with an experimental social learning task, in which pupils (N = 135; aged 11-19) could use social information from their peers to improve their performance. We show that pupils' tendencies to use social information substantially decrease with the peer's distance in the social network. This effect is mediated by subjective closeness: pupils report feeling much closer to their friends than to their non-friends, and closeness strongly enhances social learning. Our results further show that, above and beyond these effects of network distance, social information use increases with the peer's social status (network centrality) and perceived smartness. Our results provide empirical evidence in a naturalistic setting for the role of specific network attributes in shaping pupils' willingness to learn from their peers. These findings illustrate the value of a social network approach for understanding knowledge transfer in the classroom and can be used to structure more effective peer learning. Impact and ImplicationsThis study shows how social network analyses can help teachers and practitioners boost learning outcomes. Social network data can inform matching of pupils for peer learning, and can help cultivating social cohesion in the classroom. Collecting social network data is a fast and cheap procedure, and may be easily incorporated in existing protocols aimed at promoting peer learning, knowledge transfer and positive school culture.