Visual symmetry is critical to our interaction with our environment so that when detected, symmetry automatically produces a neural marker in the form of an Event Related Potential (ERP) called Sustained Posterior Negativity (SPN). However, when symmetry is presented to the visual system slanted away from the viewer, there is a reduction in SPN, termed a perspective cost. 

 

Considering ​objects are rarely presented front-on (or frontoparallel) in our natural environment, Karakashevska et al., (2023) examined the extent of the perspective cost with the addition of visual cues to facilitate extraretinal representation of the visual symmetry. The authors recorded electroencephalography (EEG) from 120 participants while they performed a luminance task on symmetrical and asymmetrical stimuli. The authors hypothesized that perspective cost would be reduced by three perspective cues: 1) monocular viewing, eliminating binocular cue conflict, 2) a static frame surrounding the symmetrical stimulus, adding a depth cue, and 3) a moving frame, providing a structure-from-motion 3D cue, prior to the symmetry onset. If the SPN was equivalent during frontoparallel and slanted presentation in a cue condition, the authors would have concluded extraretinal representation can be automatic when sufficient visual cues are available. The experiment was powered to detect a relatively small difference between perspective cue conditions.

 

The authors found that there was no impact of different visual cues on the perspective cost, as measured using the SPN. Perspective cost was consistent across all conditions, contrary to the pre-registered hypotheses. Karakashevska and colleagues conclude that the three perceptual cues tested in their design do not reduce perspective cost. The study prompts future research into the nature of the extraretinal representations of planar symmetry.  

 

The Stage 2 manuscript was evaluated over four rounds by three expert reviewers. Two of our reviewers reviewed the Stage 1 manuscript, and one new reviewer. Following in-depth review and responses from the authors, the recommenders determined that the Stage 2 criteria were met and awarded a positive recommendation.

 

URL to the preregistered Stage 1 protocol: https://osf.io/yzsq5
 
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. Karakashevska, E., Bertamini, M. & Makin, A. D. J. (2024). Putting things into perspective: Which visual cues facilitate automatic extraretinal symmetry representation? [Stage 2]. Acceptance of Version 5 by Peer Community in Registered Reports. https://doi.org/10.31234/osf.io/z9c28

Visual symmetry is critical to our interaction with our environment so that when detected, symmetry automatically produces a neural marker in the form of an Event Related Potential (ERP) called Sustained Posterior Negativity (SPN). However, when symmetry is presented to the visual system slanted away from the viewer, there is a reduction in SPN, termed a perspective cost. 

 

Considering ​objects are rarely presented front-on (or frontoparallel) in our natural environment, Karakashevska et al., (2023) plan to examine the extent of the perspective cost with the addition of visual cues to facilitate extraretinal representation of the visual symmetry. The authors will record electroencephalography (EEG) from 120 participants while they perform a luminance task on symmetrical and asymmetrical stimuli. The authors hypothesize perspective cost will be reduced by three perspective cues: 1) monocular viewing, when cue conflict caused by binocular viewing is eliminated, 2) a static frame surrounding the symmetrical stimulus, adding a depth cue, and 3) a moving frame, assisting 3D perception prior to the symmetry onset. If the SPN is equivalent during frontoparallel and slanted presentation in a cue condition, the authors will conclude extraretinal representation can be automatic when sufficient visual cues are available. The proposed experiment is powered to detect a relatively small difference between perspective cue conditions. This will solidify fundamental research on visual symmetry processing and will further our understanding of object perception and recognition. 

 

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

URL to the preregistered Stage 1 protocol: https://osf.io/yzsq5
 
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
• F1000Research
• Imaging Neuroscience
• In&Vertebrates
• NeuroImage: Reports
• Peer Community Journal
• PeerJ
• Royal Society Open Science
• Studia Psychologica
• Swiss Psychology Open

 
References
 
1. Karakashevska, E., Bertamini, M. & Makin, A. D. J. (2023). Putting things into perspective: Which visual cues facilitate automatic extraretinal symmetry representation? [Stage 1 Registered Report]. In principle acceptance of Version 4 by Peer Community in Registered Reports. https://osf.io/yzsq5