Many products that can impact upon health and wellbeing (e.g., alcohol, food) relay information to consumers about the potential risks. However, such information is commonly provided in suboptimal format for gambling-related products. To encourage safer gambling, research has therefore recommended that information about the average loss from a gambling product (“house edge”) or percentage payout (“return-to-player”) should be communicated, with the former translating to better perceived understanding by gamblers. This Registered Report aimed to experimentally compare two phrasings of the house edge against a control return-to-player to arrive at the most effective phrasing to aid gambler’s perceived chances of winning and their factual understanding of the statistical outcomes of their bet. Using a hypothetical gambling scenario, a sample of 3,333 UK-based online gamblers received one of three phrasings: an original house-edge (“his game keeps 10% of all money bet on average”), an alternative house-edge (“on average this game is programmed to cost you 10% of your stake on each bet”) or return-to-player (“this game has an average percentage payout of 90%”). Two outcome measures were employed to judge the effectiveness of this information: gamblers’ perceived changes of winning and factual understanding. The findings indicate that the two-house edge formats were more effective in communicating gambling-related harms than the return-to-player format, but the original house edge phrasing appeared to be the most optimal as it decreased gambler’s perceived chances of winning and increased their factual understanding compared to return-to-player. These results can therefore inform public health policies to reduce gambling-related harm by presenting the most effective communication of gambling risk.

 

After two in-depth reviews, the recommender judged that the manuscript met the Stage 2 criteria and awarded a positive recommendation.

 

URL to the preregistered Stage 1 protocol: https://osf.io/5npy9
 
Level of bias control achieved: Level 6. No part of the data or evidence that was used to answer the research question was generated until after IPA. 
 
List of eligible PCI RR-friendly journals:
 

References
  
1. Newall, P. W. S., James, R. J. E. & Maynard, O. M. (2023). How does the phrasing of house edge information affect gamblers’ perceptions and level of understanding? A Registered Report. Acceptance of Version 2 by Peer Community in Registered Reports. https://doi.org/10.31234/osf.io/pfnzd

​​​Making causal judgements are part of everyday life, whether seeking to understand the action of complex humans or the relations between inanimate objects in our environments. Albert Michotte’s (1963) classic book, The perception of causality, contained an extensive report of experiments demonstrating not only that observers perceive causality of inanimate shapes, but do so in manifold ways, creating different “causal impressions.” This work has been highly influential across psychology and neuroscience.

 

In the current study, White (2023) proposes a series of experiments to replicate and extend Michotte’s work. Despite the fact that this research is foundational to current work on perception and understanding of causal relations, it has never been subjected to rigorous replication. Moreover, like many research studies from that era, Michotte was sparse on details about methodology and did not rely on statistical analysis. White has proposed an ambitious set of 14 experiments that directly replicate and, in some cases, extend Michotte’s experiments. 

 

The Stage 1 manuscript was evaluated over three rounds of in-depth review, the first two rounds consisting of detailed comments from two reviewers and the third round consisting of a close read by the recommender. Based on detailed responses to the reviewers' comments, the recommender judged that the manuscript met the Stage 1 criteria and was therefore awarded in-principle acceptance (IPA). 

 

URL to the preregistered Stage 1 protocol: https://osf.io/5jx8f
 
Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists and no part will be generated until after IPA.
 
List of eligible PCI-RR-friendly journals:
 

 

 

1. Michotte, A. (1963). The perception of causality (T. R. Miles & E. Miles, trans.). London: Methuen. (English translation of Michotte, 1954).

 

2. White, P. A. (2023). Michotte's research on perceptual impressions of causality: A registered replication study. In principle acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/5jx8f 

Music is a universal across human cultures, but there is debate as to why and how it evolved. For example, Pinker has famously argued that music is “auditory cheesecake,” with no biological value (Pinker, 1997). Most scholars on the evolution of music make comparisons with language, another human universal that is unique to our species (Friederici, 2017). A current leading hypothesis in the evolution of music is the social bonding hypothesis, which suggests that music plays a special role in social bonding beyond the role that language plays (Savage et al., 2021).

 

Previous studies have provided evidence that synchronized music-making can promote social bonding (e.g. Stupacher et al., 2021). However, it is unclear whether synchronous singing provides any advantage in social bonding as compared to merely speaking. Previous work on this topic has at times lacked sufficient controls and has potentially been subject to publication bias—it could be that only the studies with statistically significant findings are in the published literature, when in fact additional experiments may have been run with unpublished null results. Also critically, prior studies have been subject to sampling bias—the vast majority are limited to a small set of cultures and musical styles, focusing primarily on English-speaking cultures and western music (Henrich & Heine, 2010). If music has evolved as a mechanism for social bonding, then it is especially critical to demonstrate its effects on social bonding across a wide range of cultures.

 

In a remarkable global collaboration including 88 collaborators from six continents, Savage et al. (2025) plan to collect data on synchronized singing and speech from 1710 participants across 57 research sites. Participants will be assigned to participate in (1) a synchronized singing activity, (2) a synchronized speech activity, or (3) a natural, prompted conversation.

 

At each research site, participants will gather in groups of 5-10 and will be randomly assigned to one of the three conditions (for the research site to be valid, it must recruit one group of participants into each condition). The experiment will start with pre-test measures of social bonding and other variables. Next, the intervention will commence. In the singing condition, participants will synchronously sing a song that is highly familiar in that culture. In the lyrics recitation condition, participants will synchronously speak printed lyrics to the songs from the singing condition (twice through, to account for speed differences in song and speech). In the conversation condition, participants will have a natural conversation in response to an ice-breaker question. Finally, each group will engage in post-test measures of social bonding as well as debriefing.

 

The social bonding hypothesis predicts that participants in the synchronized singing task will experience more social bonding (as measured by a pre- and post-test differences) than will participants who engage in sequential conversation or synchronous lyrics recitation in the absence of musical pitch or rhythm. The unprecedented scale of this global, cross-cultural investigation will make a great impact on the field and on our understanding of the relationship among speech, song, and social connection, regardless of the outcome.

 

Four expert reviewers provided valuable feedback through two rounds of review. Based on ​detailed responses to the reviewers’ and the recommender’s comments, the recommender judged that the manuscript met the Stage 1 criteria and therefore awarded in-principle acceptance.​​​

 

 

Level of bias control achieved: Level 6. No part of the data or evidence that will be used to answer the research question yet exists, and no part will be generated until after IPA.
 
List of eligible PCI RR-friendly journals:

 

• Advances in Cognitive Psychology
• Biolinguistics
• Collabra: Psychology
• Experimental Psychology *pending editorial consideration of disciplinary fit
• International Review of Social Psychology
• Journal of Cognition
• Peer Community Journal
• PeerJ
• Royal Society Open Science
• Social Psychological Bulletin
• Studia Psychologica
• Swiss Psychology Open
  
  

 

1. Friederici, A. (2017). Language in Our Brain: The Origins of a Uniquely Human Capacity. https://doi.org/10.7551/mitpress/9780262036924.001.0001

 

2. Henrich, J., Heine, S. J., & Norenzayan, A. (2010). The weirdest people in the world? Behavioral and Brain Sciences, 33, 61-83. https://doi.org/10.1017/s0140525x0999152x

 

3. Pinker, S. (1997). How the mind works. WW Norton & Company.

 

4. Savage, P. E., Loui, P., Tarr, B., Schachner, A., Glowacki, L., Mithen, S., & Fitch, W. T. (2021). Music as a coevolved system for social bonding. Behavioral and Brain Sciences, 44, e59. https://doi.org/10.1017/S0140525X20000333

 

5. Savage, P. E. et al. (2025). Does synchronised singing enhance social bonding more than speaking does? A global experimental Stage 1 Registered Report. In principle acceptance of Version 7 by Peer Community in Registered Reports. https://osf.io/7t4ck

 

6. Stupacher, J., Mikkelsen, J., & Vuust, P. (2022). Higher empathy is associated with stronger social bonding when moving together with music. Psychology of Music, 50, 1511-1526. https://doi.org/10.1177/03057356211050681

Attachment and interpersonal relationships are a major subject of research and clinical work in psychology. There are, accordingly, a proliferation of measurement instruments to tap into these broad constructs. The emphasis in these measures tends to be on the emotional dimensions of the relationships—how people feel about their partners and the support that they receive. However, that is not all there is to relationship quality. Increasing attention has been paid to the physical and physiological aspects of relationships, but there are few psychometrically sound measures available to assess these dimensions.

 

In the current study, Dujols et al. (2024) assessed the psychometric properties of the Social Thermoregulation and Risk Avoidance Questionnaire (STRAQ-1), a measure of physical relationships that targets social thermoregulation, or how physical proximity is used to promote warmth and closeness. The project consists of a thorough assessment of the measure’s reliability over time—that is, the degree to which the measure assesses the construct similarly across administrations, in a sample of 183 French university students.

 

The authors assessed the longitudinal measurement invariance and test-restest reliability of the STRAQ-1. Longitudinal measurement invariance across two time points was only found for two of the four subscales. Similarly, test-retest reliability varied by subscale, ranging from poor to good. Taken together, the study suggests caution in using the STRAQ-1 scale as a reliable measure of physical relationships. The study highlights the need for continued assessment of the reliability of widely used measures, particularly reliability over time, and serves as a model for a rigorous analytic approach for doing so.

 

The Stage 2 manuscript was evaluated over two rounds of in-depth review, the first round consisting of comments from two reviewers and the second round consisting of a close read by the recommender. Based on detailed responses to the reviewers' comments, the recommender judged that the manuscript met the Stage 2 criteria and therefore awarded a positive recommendation.

 

URL to the preregistered Stage 1 protocol: https://osf.io/pmnk2
 
Level of bias control achieved: Level 3. At least some data/evidence that was used to the answer the research question was accessed by the authors prior to Stage 1 IPA (e.g. downloaded or otherwise received) but the authors certify that they had not observed ANY part of the data/evidence until after Stage 1 IPA.
 
List of eligible PCI RR-friendly journals:
 

 

 

1. Dujols, O., Klein, R. A., Lindenberg, S., Van Lissa, C. J., & IJzerman, H. (2024). Test-Retest Reliability of the STRAQ-1: A Registered Report [Stage 2]. Acceptance of Version 10 by Peer Community in Registered Reports. https://osf.io/preprints/psyarxiv/392g6

The sunk cost fallacy is a cognitive bias in which people persist with a decision that is no longer optimal because of previous resources they have invested (now considered to be spent or “sunk”). Most of us will have heard sunk costs reflected in the saying “throwing good money after bad”, but sunk costs can, in theory, occur more broadly, whether for money, time or any other resource-limited investment. The sunk cost effect for money has been widely studied and appears robust; in contrast, the sunk cost effect for time is more uncertain, and is potentially moderated by the age of respondents (and likely resource availability), the fact that time is irreplaceable, and the tendency for people to account for time less easily than they do for money. In an impactful study, Soman (2001) found that the sunk cost effect for time was indeed weaker than for money, although this finding has not been widely replicated.

 

In the current study, Petrov et al. (2023) replicated three studies (1, 2 and 5) from Soman (2001), asking whether sunk costs are weaker for time than for money, and then testing whether the relative absence of a sunk time cost arises from the inability of participants to account for time or due to more rational beliefs in the evaluation of past time investments.

 

Results provided mixed support for the original findings. Consistent with Soman (2001), the sunk cost effect for money was reliably stronger than for time in Study 1; however, sunk costs for both money and time were comparable in Study 2 (and if anything, slightly stronger for time). The indirect replication of Study 5 from Soman (2001) found that the sunk cost effect for time was not significantly influenced by accounting for time, either using education or by highlighting opportunity costs. Robustness checks confirmed the main preregistered outcomes while also ruling out a range of potential alternative explanations. Overall, the results suggest that that sunk cost effects for time are more context-dependent and empirically volatile than sunk costs for money.
 
URL to the preregistered Stage 1 protocol: https://osf.io/65htv

 

Level of bias control achieved: Level 6. No part of the data or evidence that was used to answer the research question was generated until after IPA. 
 
List of eligible PCI RR-friendly journals:

 

 

1. Soman, D. (2001). The mental accounting of sunk time costs: Why time is not like money. Journal of Behavioral Decision Making,14, 169-185. https://doi.org/10.1002/bdm.370

 

2. Petrov, N. B., Chan, Y. K., Lau, C. N., Kwok, T. H., Chow, L. C., Lo, W. Y. V, Song W., & Feldman, G. (2023). Sunk cost effects for time versus money: Replication and extensions Registered Report of Soman (2001), acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/q9s6p