Loneliness is increasingly a focus of governments and health systems due to its potential adverse effects. Various ways to measure it have been developed but the psychometric properties of common instruments have not yet been evaluated across all countries in the European Union (EU).

 

In this study, Paris et al. (2025) will examine three measures of loneliness across 27 EU member countries. An online survey (n = 25,646) incorporated three instruments which were translated into national languages: the De Jong Gierveld Loneliness Scale (6 items), the three-item UCLA Loneliness Scale (3 items), and a single-item measure (“How much of the time, during the past 4 weeks, have you been feeling lonely”). The factor structure, internal consistency, and measurement invariance for the 6- and 3-item measures will be assessed, as well as the construct validity of all three measures using nomological networks. The authors have adopted an n-fold procedure to analyse the data, with a first exploratory fold using half of the data to establish hypotheses for each question and a second confirmatory fold using the remainder of the data to test the hypotheses. The results of the study will provide important information about the psychometric properties of commonly used loneliness instruments, and can indicate which measures are appropriate for loneliness monitoring across the EU.

 

The study plan was refined across four rounds of in-depth review with input from four reviewers, Thuy-vy Nguyen, Joe Bathelt, Mary Louise Pomeroy, and Drew Altschul, and the recommenders, after which it was judged to meet the Stage 1 criteria and received in-principle acceptance.
 
URL to the preregistered Stage 1 protocol: https://osf.io/2s38v

 
Level of bias control achieved: Level 3. At least some data/evidence that will be used to the answer the research question has been previously accessed by the authors (e.g. downloaded or otherwise received), but the authors certify that they have not yet observed ANY part of the data/evidence
 
List of eligible PCI RR-friendly journals:
 

 

 

Paris, B., Ropovik, I., Silan, M., d'Hombres, B., Casabianca, E., & IJzerman, H. (2025). Evaluating Loneliness Measurements across the European Union. In principle acceptance of Version 4 by Peer Community in Reigstered Reports. https://osf.io/2s38v

 

The relationship between music and exercise has been studied for over a century, with implications for our understanding of biomechanics, physiology, brain function, and psychology. Listening to music while exercising is associated with a wide range of benefits, from increasing motivation, to reducing perceived exertion, inhibiting awareness of negative bodily signals, boosting mood, and ultimately improving physical performance. But while these ergogenic benefits of music are well documented, much remains to be discovered about how music alters brain function during exercise. One reason for this gap in understanding is the technical difficulty in recording brain activity during realistic exercise, as neuroimaging methods such as fMRI, EEG or MEG typically require participants to remain as still as possible.

 

In the current study, Guérin et al. (2023) will use the optical brain imaging technique of functional near infrared spectroscopy (fNIRS) to measure oxygenation of key brain areas during exercise. Unlike other neuroimaging methods, fNIRS has a high tolerance for motion artefacts, making it the ideal method of choice for the current investigation. The authors propose a series of hypotheses based on previous studies that observed a decrease in cerebral oxygenation during intense exercise, particularly within the medial prefrontal cortex (mPFC) and dorsolateral prefrontal cortex (dlPFC). If, as suggested, the prefrontal cortex is important for regulation of cognition and emotion during exercise, then the benefits of listening to music might arise by delaying or reducing this drop in prefrontal oxygenation.

 

Using a within-subject designs, Guérin et al. will combine an incremental exercise protocol involving a cycling task with three auditory conditions: asynchronous music (the active condition), listening to an audiobook (an auditory control) or silence (baseline control). Compared to the two control conditions, they predict that music exposure will increase oxygenation in prefrontal and parietal regions and will also delay the drop in oxygenation associated with intense exercise (specifically within dlPFC and mPFC). To test whether any such changes are specific for prefrontal and parietal cortex, they will also compare the haemodynamic responses of the occipital cortex between the auditory conditions, predicting no difference.

 

The Stage 1 manuscript was evaluated over two rounds of in-depth review. Based on detailed responses to the reviewers' comments, the recommender judged that the manuscript met the Stage 1 criteria and therefore awarded in-principle acceptance (IPA).

 

URL to the preregistered Stage 1 protocol: https://osf.io/52aeb
 
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:
 

In neurostimulation research, the parameters of a stimulation protocol crucially impact on the effects of the stimulation. Transcranial direct current stimulation (tDCS) is a neurostimulation technique that typically uses current intensities about 1-2 mA in human research to modulate motor and cognitive behavior. The current sham-controlled study by Hsu et al. (2024) applies current intensities not only of 2 mA but also of 4 mA and 6 mA and thus extends our understanding of stimulation parameters while ethical standards are preserved.

 

The influence of tDCS over the primary motor cortex will be evaluated for neural plasticity during motor learning. Stimulation effects will be tested not only behaviorally but also physiologically by motor evoked potentials elicited by transcranial magnetic stimulation (TMS). The presented pilot data are promising and underline the feasibility of the proposed research design. The study will contribute to tDCS research by uncovering reasons for controversial findings and thus increase reproducibility.

 

The Stage 1 manuscript was evaluated over two rounds of in-depth review. Based on detailed responses to the reviewers' comments, the recommender judged that the manuscript met the Stage 1 criteria and therefore awarded in-principle acceptance (IPA).

 

URL to the preregistered Stage 1 protocol: https://osf.io/jyuev
 
Level of bias control achieved: Level 2. At least some data/evidence that will be used to answer the research question has been accessed and partially observed by the authors, but the authors certify that they have not yet observed the key variables within the data that will be used to answer the research question.
 
List of eligible PCI RR-friendly journals:

 

• Brain and Neuroscience Advances
• Imaging Neuroscience
• NeuroImage: Reports
• Peer Community Journal
• PeerJ
• Royal Society Open Science
• Studia Psychologica

 

 

Hsu, G., Edwards, D. J., Cohen, L. G., & Parra, L. C. (2024). Dose-response of tDCS effects on motor learning and cortical excitability: a preregistered study. In principle acceptance of Version 1.3 by Peer Community in Registered Reports. https://osf.io/jyuev

This Stage 1 registered report by Szecsi et al. (2024) seeks to clarify whether individuals' economic conditions moderate how scarcity cues affect their attentional performance. This idea has been previously explored: Here, the authors aim to clarify understanding of the how scarcity cues affect cognition by studying a large and diverse Hungarian sample with improved experimental methods.

 

Specifically, while it has been previously reported that financially less well-off individuals' are differentially affected by finance-related stimuli (e.g. Shah et al., 2018), Szecsi et al. (2024) argue that prior studies have used small samples with insufficient consideration of potentially important demographic variables. Therefore, the generalizability of prior studies might be lacking.

 

Second, Szecsi et al. (2024) aim to conduct a more realistic experiment by asking participants to free-associate in response to financial scarcity-related cues, whereas prior studies have often focused on simply querying for rating responses, which might not sufficiently engage the related cognitive mechanisms that could be most affected.

 

In the proposed study, then, the authors will rigorously test whether financially less well-off individuals have lower attentional performance while experiencing scarcity-related cues than individuals who are financially better off, and that attentional performance does not differ while experiencing non-scarcity related cues. Ultimately, Szecsi et al. propose to shed light on theories of scarcity-related cognition that posit overall decrements in attentional performance irrespective of individuals' financial status.

 

The Stage 1 manuscript was initially reviewed by two experts in the area, who both recommended several improvements to the study. The authors then thoroughly revised their write-up and protocol, and the two reviewers were satisfied with the substance of these revisions. Based on these evaluations, the recommender judged that the Stage 1 criteria were met and awarded in-principle acceptance. There were remaining editorial clarifications and suggestions which the authors can incorporate in their eventual Stage 2 report.

 

URL to the preregistered Stage 1 protocol: https://osf.io/3zdyb
 
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
• Collabra: Psychology
• Experimental Psychology
• Journal of Cognition
• Peer Community Journal
• PeerJ
• Psychology of Consciousness: Theory, Research, and Practice
• Royal Society Open Science
• Studia Psychologica
• Swiss Psychology Open

 

 

1. Shah, A. K., Zhao, J., Mullainathan, S., & Shafir, E. (2018). Money in the mental lives of the poor. Social Cognition, 36, 4-19. https://doi.org/10.1521/soco.2018.36.1.4

 

2. Szecsi, P., Bognar, M., & Szaszi, B., (2024). Do Scarcity-Related Cues Affect the Sustained Attentional Performance of the Poor and the Rich Differently? In principle acceptance of Version 2 by Peer Community in Registered Reports. https://osf.io/3zdyb

The Martyrdom Effect is a behavioral tendency in which individuals exhibit greater generosity when their acts of giving entail effort or self-sacrifice (Olivola & Shafir, 2013). Giving at a personal cost, in this mindset, is associated with ascribing and inferring more meaning and value to charitable giving or other forms of generosity than in instances where no particular pain or effort is required to enact prosocial behavior. Arguably, the Martyrdom Effect’s ability to boost prosocial behavior therefore departs from other theories of behavior change postulating that easy options to act prosocially could boost contributions (e.g., default effects in charitable giving, see Altmann et al., 2019; Goswami & Urminsky, 2016). Because they introduce complexity to the debate about encouraging prosocial behavior, three studies from Olivola and Shafir (2013) are now being addressed in this Registered Report by Cheng and Feldman (2024).

Combining these three studies in a high-powered within-subjects replication attempt, transparently communicating necessary deviations from the original design and carefully outlining the analysis strategy, the current study will offer insights into the robustness of prior findings on the role of effort and pain in determining donations.

The Stage 1 manuscript was evaluated by two reviewers and the recommender. Based on detailed responses to the reviewers' comments, the recommender judged that the manuscript met the Stage 1 criteria and therefore awarded in-principle acceptance (IPA).

 

 

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. Altmann, S., Falk, A., Heidhues, P., Jayaraman, R., & Teirlinck, M. (2019). Defaults and Donations: Evidence from a Field Experiment. The Review of Economics and Statistics, 101, 808-826. https://doi.org/10.1162/rest_a_00774

 

2. Cheng, Y. T. & Feldman, G. (2024). Do pain and effort increase prosocial contributions?: Revisiting the Martyrdom Effect with a Replication and extensions Registered Report of Olivola and Shafir (2013). In principle acceptance of Version 2 by Peer Community in Registered Reports. https://osf.io/aq89u

 

3. Goswami, I., & Urminsky, O. (2016). When should the Ask be a Nudge? The Effect of Default Amounts on Charitable Donations. Journal of Marketing Research, 53, 829-846. https://doi.org/10.1509/jmr.15.0001

 

4. Olivola, C. Y., & Shafir, E. (2013). The Martyrdom Effect: When Pain and Effort Increase Prosocial Contributions. Journal of Behavioral Decision Making, 26, 91-105. https://doi.org/10.1002/bdm.767