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
 
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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

 

Chronic pain is a major cause of disability that can often poorly managed with pharmacological treatments. This has prompted the exploration of other interventions like resizing illusions of body parts in augmented reality. These illusions have shown promise in conditions like osteoarthritis and complex regional pain syndrome, but it remains unclear how they alter the neural representation of body parts in the brain. The study by Hansford and colleagues aims to investigate these mechanisms in healthy participants, using somatosensory steady state evoked potentials (SSEP) and self-report questionnaires.

 

The study will involve finger stretching in an augmented reality setup that allows the researchers to independently manipulate visual and tactical stimulation. Assuming that multisensory stimulation indeed produces a robust illusion, the researchers will quantify the somatosensory evoked potentials in multisensory, unisensory, and two non-illusion control conditions. The study will provide inights into the neural mechanisms of these illusions and lay the ground for future investigations of these processes as a potential treatment for chronic pain.

 

The manuscript was evaluated over seven rounds of in-depth review by the recommender and three expert reviewers. After substantial revisions, the recommender judged that the manuscript met the Stage 1 criteria and awarded in-principle acceptance (IPA).

 

URL to the preregistered Stage 1 protocol: https://osf.io/u6gsb
 
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.
 
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References
 
1. Hansford, K. J., Baker, D. H., McKenzie, K. J., & Preston, C. E. J. (2023). Somatosensory Response Changes During Illusory Finger Stretching. In principle acceptance of Version 7 by Peer Community in Registered Reports. https://osf.io/u6gsb

For many of us, music is far more than an auditory experience. It can trigger emotional reactions, evoke memories, and wide-ranging associations with other sensory modalities and cognitive states. Music also varies between different cultures in several ways. It remains unclear in how far the broader associations music has differs between cultural contexts, both in terms of the music itself and the listener. This study by Hadavi et al. (2024) seeks to better understand these relationships. Using an online survey targeted at 72 participants from anglophone Canada, Farsi-speaking Iran, and Japan (24 from each location), the researchers aim to address two straightforward hypotheses.

 

First, does faster tempo of music increase ratings of emotional arousal? Second, do participants match faster tempo music with denser visual line patterns? This latter measure aims to quantify the visual imagery evoked by the musical pieces. Imagery is a loaded term that is not used consistently across the cognitive neuroscience literature; one could argue that what the researchers are actually here is in fact mainly an association between tempo and a visual representation of tempo (or frequency). It certainly seems doubtful that persons listening to a piece of music will form a mental image of a bundle of horizontal lines. Yet, irrespective of how to interpret this experimental variable, it quantifies something about the impression listeners have when experiencing music, and whether these associations differ cross-culturally. The experiment has a balanced design, incorporating excerpts of musical pieces from each of the three cultural contexts, including both solo and group music. While the sample size is comparably low, given the online nature of data collection, it is based on a power analysis and relatively large expected effect sizes.

 

The proposed study was evaluated by three expert reviewers and the recommender over three rounds of in-depth review, plus a final round ironing out smaller issues. Reviewer Juan David Leongómez was recruited as a co-author after the first round of revisions. Following this process, the recommender decided that the manuscript met Stage 1 criteria and 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:

 

References
 
1.Hadavi, S., Kuroda, J., Shimozono, T., Leongómez, J. D. & Savage, P. E. (2024). Cross-cultural relationships between music, emotion, and visual imagery: A comparative study of Iran, Canada, and Japan. In principle acceptance of Version 6 by Peer Community in Registered Reports. https://osf.io/zdnkm

Many studies of unconscious processing measure priming effects. Such experiments test whether a prime stimulus can exert an effect on speeded responses to a subsequently presented target stimulus even when participants are unaware of the prime. In some studies, participants are required to report their awareness of the prime in each trial - a dual-task design. Other studies conduct such visibility tests in separate experiments, so that the priming effect is measured via a single task. Both these approaches have pros and cons; however, it remains unclear to what extent they can affect the process of interest. Can the choice of experimental design and its parameters interfere with the priming effect? This could have implications for interpreting such effects, including in previous literature.

 

In the current study, Wendt and Hesselmann (2024) will investigate the effects of using a dual-task design in a masked priming paradigm, focusing on subjective visibility judgments. Based on power analysis, the study will test 34 participants performing both single-task and several dual-task conditions to measure reaction times and priming effects. Priming is tested via a speeded forced-choice identification of a target. The key manipulation is the non-speeded visibility rating of the prime using a Perceptual Awareness Scale, either with a graded (complex) rating or a dichotomous response. Moreover, participants will either provide their awareness judgement via a keyboard or vocally. Finally, participants will also complete a control condition to test prime visibility by testing the objective identification of the prime. These conditions will be presented in separate blocks, with the order randomised across participants. The authors hypothesise that using a dual-task slows down response times and boosts priming effects. However, they further posit that keyboard responses and graded visibility ratings, respectively, in the dual task reduce priming effects (but also slow response times) compared to vocal responses and dichotomous visibility judgements. In addition to the preregistered hypotheses, the study will also collect EEG data to explore the neural underpinnings of these processes.

 

The Stage 1 manuscript went through three rounds of review by the recommender and five expert reviewers. While the recommender would have preferred to see targeted, directional hypotheses explicitly specified in the design instead of non-directional main effects/interactions, he nevertheless considers this experimental design ready for commencing data collection, and therefore granted 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:

 

Wendt, C. & Hesselmann, G. (2024). Probing the dual-task structure of a metacontrast-masked priming paradigm with subjective visibility judgments. In principle acceptance of Version 4 by Peer Community in Registered Reports. https://osf.io/ds2w5

Higher-level cognitive processes like attention, memory, or mental imagery can produce pupil responses, without any actual difference in luminance of the visual stimulus. Interestingly, the inverse scenario remained untested to date: when a physical luminance difference is perceptually eliminated from awareness, does pupil size still track attention to the stimulus? In this Registered Report, Vilotijević and Mathôt (2024) sought to test this experimentally using a perceptual fading phenomenon where two Gaussian patches with different luminances fade from consciousness and are thus perceived as mid-level uniform grey (or at least the subjective difference is much reduced). This fading manipulation, as well as a control condition without perceptual fading, were presented in separate blocks. Participants were instructed to covertly attend one of the patches.

The authors hypothesised that if pupil size reflects attentional selection, these pupil responses in the fading condition​ should be eliminated or at least reduced, and this should evolve with time as the stimuli are perceptually fading. Their results show that pupil responses during covert attention are indeed reduced during perceptual fading - but they are not eliminated. Interestingly, this reduction did not depend on time or self-reports of the strength of perceptual fading. The findings therefore suggest that pupil dilation tracks subjective brightness differences.

 

One inherent issue with experiments like these is that the experimental and control conditions necessarily involve a physical difference in the stimulus. Here, the fading condition had the same spatial configuration of light and dark stimuli throughout a block while in the control (non-fading) condition the light and dark stimuli alternated sides between trials. It is therefore impossible to completely rule out that the physical difference affects the results. However, the only alternative to this would be an experimental design in which the stimuli never change, but only the subjective perceptual state varies. Such a design is completely at the mercy of the participant's subjective state and therefore loses experimental control and statistical sensitivity. The present results confirmed the authors' prediction that there are indeed differences in overall pupil responses during the fading and control conditions, irrespective of covert attention.

 

Critically, the fact that the attention effect did not vary with time or subjective self-reports of the illusion supports the authors' interpretation that this reflects higher-level cognition: the mere act of attending to the dark side - even if the actual appearance has faded - could cause a sustained pupil dilation. This would be consistent with the type of pupil effects for memory and mental imagery that motivated the present study. However, a simpler alternative is that the experience of perceptual fading was incomplete (as possibly suggested by Figures 2D and 2F) but that self-reports fail to capture this subjective experience accurately. Perhaps a future study could compare the magnitude of the attentional pupil effects when the initial stimulus is completely removed. If similar differences in pupil response persist this would suggest that the present results are due to high-level modulation or the residual low-level luminance difference.

 

The Stage 2 manuscript was evaluated by two reviewers and the recommender over two rounds of review. One reviewer again advised additional robustness checks to rule out eye movement confounds, an issue they had already raised during Stage 1 review. The researchers provide clear evidence that this is unlikely to have confounded their findings. This has been added to the supplementary data repository. Following this review and revision, the recommender judged that the Stage 2 criteria were met and awarded a positive recommendation.

 

URL to the preregistered Stage 1 protocol: https://osf.io/bmtp6
 
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. Vilotijević, A. & Mathôt, S. (2024). The effect of covert visual attention on pupil size during perceptual fading [Stage 2]. Acceptance of Version 2 by Peer Community in Registered Reports. https://osf.io/ku8qc?view_only=f331df53b50f431386fabba9e386b387