Much of how we use our perception involves judgements on how similar things are: You might vaguely recognise an actor's face in a movie but not immediately recognise where you have seen it before. Some people claim to be "bad with faces". Is that in fact based on objectively poorer ability to recognise faces? Psychophysical lab studies of perception typically use forced-choice discrimination tasks in which participants must make explicit, and usually binary, decisions. Such designs can yield parametric information about underlying perceptual processes, but it is very different from how we use perception in daily life.

 

Here, Moharramipour and colleagues (2024) seek to better understand the link between such subjective similarity jugdements and objective discrimination ability. They argue that subjective similarity can be considered a metacognitive process, reflecting the person's awareness of their perceptual capacity. Participants will be asked to discriminate face pairs across a spectrum of morphing steps in a classical forced-choice paradigm to estimate perceptual threshold performance, as well as provide subjective ratings of similarity of the face pairs. The researchers hypothesise a correlation between objective perceptual ability and subjective similarity judgements. They will evaluate this at the group level, and also use a resampling approach to determine the specificity of this relationship in individual participants. Confirming this hypothesis would advance our knowledge of how perceptual ability links with our metacognitive introspection of it. Are you really "bad with faces" or do you only think you are?

 

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 awarded in-principle acceptance (IPA).

 

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

 

 

Moharramipour, A., Zhou, W., Rahnev, D., & Lau, H. (2024). Is subjective perceptual similarity metacognitive? In principle acceptance of Version 4 by Peer Community in Registered Reports. https://osf.io/pzugy

Previous research has shown that 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 remains untested: when a difference in luminance is perceptually eliminated from awareness, does pupil size still track cognitive factors? In this study, Vilotijević and Mathôt (2024) seek 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. The researchers will present this fading manipulation and a control condition where no fading occurs in separate blocks. Participants are instructed to covertly attend one of the patches. If pupil size reflects attentional selection, pupil responses should be reduced in the fading condition, and this should evolve with time as the stimuli are perceptually fading.

 

The Stage 1 manuscript was evaluated by three reviewers and the Recommender over three rounds of review. One reviewer advises conducting robustness checks to rule out eye movements confounds. This constitutes exploratory analyses at Stage 2 that probably require some flexibility. Despite this, the Recommender decided to grant in-principle acceptance of this study. While these robustness tests can put the eventual results in context, the general hypotheses and predictions specified in this version are clear and straightforward.

 

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 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. Vilotijević, A. & Mathôt, S. (2024). The effect of covert visual attention on pupil size during perceptual fading. In principle acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/bmtp6

 

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

 

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

Do people who are more alert towards social stimuli vary in loneliness? This report addresses the question how loneliness relates to hypersensitivity to social stimuli using an oddball paradigm. Based on preliminary results, the study plans to compare high and low lonely individuals for how they react to happy and angry facial expressions using neurophysiological correlates. Findings from the study will provide further insights in how loneliness might be related to processing of social information.

 

The Stage 1 manuscript was evaluated over two rounds of in-depth review. Based on detailed responses to the reviewers' and recommender's comments, 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/fxngv
 
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
• Brain and Neuroscience Advances
• Cortex
• Imaging Neuroscience
• Journal of Cognition
• NeuroImage: Reports
• Peer Community Journal
• PeerJ
• Royal Society Open Science
• Studia Psychologica
   

References
 
1. Bathelt, J., Dijk, C., & Otten, M. (2024). Loneliness in the Brain: Distinguishing Between Hypersensitivity and Hyperalertness. In principle acceptance of Version 5 by Peer Community in Registered Reports. https://osf.io/fxngv

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

Language production is associated with a distinct lateralised pattern of brain activation biased toward the left cerebral hemisphere. This also applies to writing. It has also been shown to be modulated by handedness, with less pronounced lateralisation in left-handers. However, in recent decades the use of handwriting has declined significantly while the use of smartphones has exploded. To date, no study has explored whether the same neural correlates of written language production found for handwriting also hold for typing on a smartphone.

 

In the current study, Samsouris et al. (2023) will use functional transcranial Doppler ultrasound (fTCD) to measure blood flow velocity within cerebral hemispheres to investigate this question. This technique is particularly suited for this purpose because it provides better control for the movement confounds associated with a writing task and the technical challenges of using a smart device than other neuroimaging techniques like fMRI or M/EEG. The authors hypothesise that there will be no difference in left cerebral lateralisation for handwriting and typing on a smartphone. They also expect to replicate previous findings of weaker lateralisation in left-handers in written language production when typing on a smartphone. To isolate the effect of written language production, both these conditions will be corrected for their corresponding motor component using control conditions without a linguistic component.

 

The Stage 1 manuscript was evaluated over 6 rounds of in-depth review by the recommender and two expert reviewers, before issuing in-principle acceptance.

 

URL to the preregistered Stage 1 protocol: https://osf.io/j7egz
 
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. Samsouris, C., Badcock, N. A., Vlachos, F., & Papadatou-Pastou, M. (2023). Cerebral laterality as assessed by functional transcranial Doppler ultrasound in left-and right-handers: A comparison between handwriting and writing using a smartphone. In principle acceptance of Version 7 by Peer Community in Registered Reports. https://osf.io/j7egz

Vocal sounds, including both speech and non-speech sounds, have been found to activate the Superior Temporal Sulci and Gyri in comparison to non-vocal sounds. These regions, termed Temporal Voice Areas (TVAs), are considered to be involved in early voice processing and therefore critical for social interaction. TVA activation has been examined in Autism Spectrum Disorder (ASD) to determine if the characteristic difficulties in social communication and interaction are linked to an impaired early voice processing. Using functional magnetic resonance imaging (fMRI), one study found typical brain activation in TVAs for 15 out of 16 autistic participants (Schelinski et al., 2016), whereas another found atypical activation in 4 out of 5 autistic participants (Gervais et al., 2004).

 

Here, the inconsistencies in the previous literature propel Gautier et al. (2023) to examine brain activation of TVAs with a larger sample size (26 ASD and 26 non-ASD participants). Gautier et al. (2023) will present vocal sounds and non-vocal sounds to both groups of participants during fMRI and predict that fewer participants in the ASD group will show a preferential response to voices in TVAs compared to the non-ASD group. These results would suggest that symptoms of ASD interfere with early stages of social interaction, at the level of voice processing.

 

This Stage 1 manuscript was evaluated in an initial round by the co-recommenders and another two rounds of in-depth review by two expert reviewers. With these revisions, the recommenders 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/538m4
 
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. Gautier, R., Houy-Durand, E., Barantin, L., Briend, F. & Latinus, M. (2023). Cortical voice processing in Autism Spectrum Disorder. In principle acceptance of Version 4 by Peer Community in Registered Reports. https://osf.io/538m4

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.
 
List of eligible PCI RR-friendly journals:
 

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

Data sharing is perhaps the most fundamental step for increasing the transparency and reproducibility of scientific research. However, the goals of open science must be tempered by ethical considerations, protecting the privacy and safety of research participants. Bridging this gap causes challenges for many fields, such as human neuroimaging. Brain images, as measured with magnetic resonance imaging (MRI), are unique to the participant and therefore contain identifying information by definition. One way to mitigate the risk to participants arising from public data sharing has been "defacing" the MRI scans, i.e., literally removing the part of the image that contains the face and surrounding tissue, while preserving the brain structure. This procedure however also removes information that is not (or at least minimally) identifiable. It also remains unclear whether defacing the images affects image quality and thus the information necessary for addressing many research questions.

 

The current study by Provins et al. (2023) seeks to address this question. Leveraging a publicly available "IXI dataset" comprising hundreds of T1-weighted structural MRI scans, they will assess the effect of defacing on manual and automatic estimates of image quality. Specifically, the researchers will compare image quality ratings by experts for a subset of 185 images. They hypothesise that images in which facial features have been removed are typically assigned higher quality ratings. Moreover, using a full data set of 580 images, which have been obtained across three scanning sites, they will also test the impact defacing MRI scans has on automated quality measures obtained with MRIQC software. The results of this study should have important implications for open science policy and for designing the optimal procedures for sharing structural MRI data in an ethical way. For example, if the authors' hypothesis is confirmed, studies relying on MRI quality measures might be better served by a custodianship model where identifiable data is shared under strict conditions, rather than relying on publishing defaced data. More generally, the outcome of this study may have significant legal implications in many jurisdictions.

 

The Stage 1 manuscript was evaluated at the inital triage stage by the Recommender and PCI:RR team, and another round of in-depth review by two experts. After a detailed response and substantial revisions, the recommender judged the manuscript met the Stage 1 criteria and awarded in-principle acceptance (IPA).

 

URL to the preregistered Stage 1 protocol: https://osf.io/qcket (under temporary private embargo)
 
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 AND they have taken additional steps to maximise bias control and rigour.
 
List of eligible PCI RR-friendly journals:
 

 

1. Provins, C., Savary, E., Alemán-Gómez, Y., Richiardi, J., Poldrack, R. A., Hagmann, P. & Esteban, O. (2023). Defacing biases in manual and automated quality assessments of structural MRI with MRIQC, in principle acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/qcket