Expectancy Effects Threaten the Inferential Validity of Synchrony-Prosociality Research

GrooVR: an open access virtual reality drumming application to improve pro-sociality using synchronous movement

Interpersonal synchrony can enhance social bonding, cooperation, and reduce negative biases, especially toward out-group members. However, studying social synchrony faces practical challenges. To address this, we introduce a customizable virtual reality (VR) application and report two experiments evaluating its effectiveness. In the first experiment, participants drummed either in sync or out of sync with a virtual partner matching their gender, age, and ethnicity. Synchronous drumming increased feelings of affiliation but did not influence pro-social behavior in an economic game. The second experiment involved Caucasian participants drumming with Middle Eastern avatars. Synchronous drumming not only increased trust and affiliation but also reduced prejudicial attitudes toward Middle Eastern refugees. These findings suggest that virtual synchrony can strengthen social bonds and decrease bias, offering both theoretical insights and practical applications.

The Game Within the Game: The Potential Influence of Demand Characteristics and Participant Beliefs in Violent Video Game Studies

In two experiments, we examined the potential impact of demand characteristics in violent video game (VVG) research. Study 1 (N = 788) measured behavioral aggression, while Study 2 (N = 1,182) measured trait aggression. Participants were informed either that researchers wanted to confirm that VVGs increase aggression ("Positive Hypothesis") or that VVGs have no effect ("Null Hypothesis"). Study 2 included a third condition where participants were given no information. In both studies, the interaction between VVG exposure and experimental conditions was significant. Whereas VVG exposure was significantly positively associated with aggression in the "Null Hypothesis" condition, it was not in the "Positive Hypothesis" condition. These effects were driven by habitual players responding differently based on the presented hypothesis, appearing less aggressive in the "Positive Hypothesis" condition than in the other two conditions. These findings highlight the importance of addressing demand characteristics in VVG studies.

An observation of a negative effect of social cohesion on creativity in musical improvisation

Although various social factors can significantly impact creative performance, it is still unclear how social cohesion (i.e., how close we feel to others) influences creativity. We therefore conducted two studies exploring the association between social cohesion and creativity within the domain of musical improvisation, a prime example of creative performance, which usually plays out in social contexts. The first study (n = 58 musical novices) showed that music-induced synchrony facilitates social cohesion. In our second study (n = 18 musical novices), we found that in two out of three experimental conditions, increased social cohesion is associated with less creative musical outcomes, as rated by nine expert musicians. In our subsequent analysis we related measures of social cohesion and creativity. This approach highlights how, within a musical setting, creativity unfolds in the context of social contingencies as social cohesion and related factors.

The Synchrony-Prosociality Link Cannot Be Explained Away as Expectancy Effect: Response to Atwood et al. ()

Moving in time to others, as is often observed in dance, music, sports and much of children's play cross-culturally, is thought to make people feel and act more prosocially towards each other. In a recent paper, Atwood et al. (2022) argued that the inferential validity of this link found between synchronous behaviour and prosociality might be mainly due to "expectancy effects generated by a combination of (1) experimenter expectancy, leading to experimenter bias; and (2) participant expectancy (i.e., placebo effects)". Here, we counter these arguments with (1) examples of studies devoid of experimenter expectancy effects that nevertheless demonstrate a positive link between synchrony and prosociality, and (2) insights from the developmental literature that address participant expectancy by showing how expectations formed through lived experiences of synchronous interactions do not necessarily threaten inferential validity. In conclusion, there is already sufficient good-quality evidence showing the positive effects of synchronous behaviours on prosociality beyond what can be explained by experimenter or participant expectation effects.

Musical coordination affects children's perspective-taking, but musical synchrony does not

Perspective-taking, which is important for communication and social activities, can be cultivated through joint actions, including musical activities in children. We examined how rhythmic activities requiring coordination affect perspective-taking in a referential communication task with 100 Chinese 4- to 6-year-old children. In Study 1, 5- to 6-year-old children played an instrument with a virtual partner in one of three coordination conditions: synchrony, asynchrony, and antiphase synchrony. Eye movements were then monitored with the partner giving instructions to identify a shape referent which included a pre-nominal scalar adjective (e.g., big cubic block). When the target contrast (a small cubic block) was in the shared ground and a competitor contrast was occluded for the partner, participants who used perspective differences could, in principle, identify the intended referent before the shape was named. We hypothesized that asynchronous and antiphase synchronous musical activities, which require self-other distinction, might have stronger effects on perspective-taking than synchronous activity. Children in the asynchrony and antiphase synchrony conditions, but not the synchrony condition, showed anticipatory looks at the target, demonstrating real-time use of the partner's perspective. Study 2 was conducted to determine if asynchrony and antiphase asynchrony resulted in perspective-taking that otherwise would not have been observed, or if synchronous coordination inhibited perspective-taking that would otherwise have occurred. We found no evidence for online perspective-taking in 4- to 6-year-old children without music manipulation. Therefore, playing instruments asynchronously or in alternation, but not synchronously, increases perspective-taking in children of this age, likely by training self-other distinction and control. A video abstract of this article can be viewed at https://youtu.be/TM9h_GpFlsA. RESEARCH HIGHLIGHTS: This study is the first to show that rhythmic coordination, a form of non-linguistic interaction, can affect children's performance in a subsequent linguistic task. Eye-movement data revealed that children's perspective-taking in language processing was facilitated by prior asynchronous and antiphase synchronous musical interactions, but not by synchronous coordination. The results challenge the common "similar is better" view, suggesting that maintaining self-other distinction may benefit social interactions that involve representing individual differences.