​Karakashevska and colleagues (2025) examined the extraretinal representation of visual symmetry presented in a virtual reality environment. Previous research has demonstrated that individuals can detect symmetry when the symmetry is represented on a perspective plane, slanted away from the viewer. In electroencephalography (EEG), perceived symmetry is marked by an Event Related Potential (ERP) called a Sustained Posterior Negativity (SPN). When symmetry is presented on a perspective plane in comparison to front-on (frontoparallel), the SPN is reduced, termed the perspective cost. Here, Karakashevska et al. (2025) determined if presenting symmetry on a perspective plane in a virtual reality (VR) environment reduced the perspective cost with the addition of 3D depth cues. Specifically, participants were requested to detect symmetry or luminance of a stimulus presented in a VR environment whilst wearing an EEG.

 

The authors found no perspective cost during the regularity task when symmetry was presented on a frontoparallel plane versus symmetry on a perspective plane. When participants were performing the luminance task, the authors found no conclusive evidence for the presence or absence of perspective cost. Together these data suggest that when immersed in a virtual reality (VR) environment, critical depth cues are available to overcome perspective cost in the perception of symmetry. 

 

The Stage 2 manuscript was evaluated by two expert reviewers. One of our reviewers reviewed the Stage 1 manuscript, and one reviewer was new. The reviewers agreed that the authors had adhered to their registered Stage 1 manuscript and were convinced by the interpretation of the results. The recommender has determined that the Stage 2 criteria was met and has awarded a positive recommendation. ​

 

URL to the preregistered Stage 1 protocol: https://osf.io/7pnxu
 
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:

 

• Advances in Cognitive Psychology
• Brain and Neuroscience Advances
• Cortex
• Imaging Neuroscience
• NeuroImage: Reports
• Peer Community Journal
• PeerJ
• Psychology of Consciousness: Theory, Research, and Practice
• Royal Society Open Science
• Studia Psychologica

 

 

Karakashevska, E., Batterley, M/, Yuxin, Y., & Makin, A. D. J. (2025). They look virtually the same: extraretinal representation of symmetry in virtual reality [Stage 2]. Acceptance of Version 2 by Peer Community in Registered Reports. https://doi.org/10.31234/osf.io/sfyg6_v2

 

​Karakashevska and colleagues (2024) aim to examine the extraretinal representation of visual symmetry presented in a virtual reality environment. Previous research had demonstrated that individuals can detect symmetry when the symmetry is represented on a perspective plane, slanted away from the viewer. In electroencephalography (EEG), perceived symmetry is marked by an Event Related Potential (ERP) called a Sustained Posterior Negativity (SPN). When symmetry is presented on a perspective plane in comparison to front-on (frontoparallel), the SPN is reduced, termed the perspective cost. Here, Karakashevska et al., (2024) will determine if presenting symmetry on a perspective plane in a virtual reality (VR) environment will reduce the perspective cost with the addition of 3D depth cues. Specifically, participants will be requested to detect symmetry or luminance of a stimulus presented in a VR environment whilst wearing an EEG. The authors hypothesize that no perspective cost will be identified between symmetry presented on a frontoparallel plane versus symmetry on a perspective plane. Furthermore, the authors will examine the impact of task within the virtual environment on symmetry processing. They hypothesize that a task focused on the regularity of the stimuli will result in a larger amplitude of the SPN than a luminance task. This design enables the authors to pinpoint immersive environments as providing cues critical in overcoming perspective cost.

 

The Stage 1 manuscript was evaluated by two expert reviewers across three rounds. Following in-depth review and responses from the authors, the recommender has determined that Stage 1 criteria was met and has awarded in-principle acceptance (IPA).

 

URL to the preregistered Stage 1 protocol: https://osf.io/7pnxu
 
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:

 

 

Karakashevska, E., Batterley, M. & Makin, A. D. J. (2024). They look virtually the same: extraretinal representation of symmetry in virtual reality. In principle acceptance of Version 3 by Peer Community in Registered Reports. https://osf.io/7pnxu