One of the hallmarks of adaptive behaviour is perceptual decision-making: the ability to select and integrate sensory inputs to guide judgments and actions. For decades, evidence accumulation models (EAMs) have been influential in shaping understanding of perceptual decision-making, proposing that evidence for different choices builds over time until a threshold is reached and a decision is triggered. At the same time, reliable biomarkers for evidence accumulation have been observed through single-unit recordings in non-human primates, particularly in parietal, frontal and premotor regions. In humans, the centro-parietal positivity (CPP) –  a positive deflection in the event-related potential (ERP) waveform – has emerged as a candidate proxy of perceptual decision-making, exhibiting accumulate-to-bound dynamics, modality-independence, and versatility to sensory inputs. However, much remains to be understood about the generalisability of the CPP across different behavioural contexts, from simple decision-making tasks (e.g. motion discrimination) to more complex judgments (e.g. emotion discrimination).

 

In the current study, Liu et al. (2025) will test the robustness of the CPP in human decision-making by leveraging secondary analysis of existing datasets. Broadly, they hypothesise that if the CPP is a reliable and generalisable biomarker then it should covary statistically with evidence accumulation, both at the trial level and across tasks that increase in complexity. To test this prediction, the authors will undertake joint modelling of behavioural and ERP data using drift-diffusion modelling, capturing variability within and between trials to estimate the relationship between the CPP and drift rate. In addition, the authors will use multiverse analysis to test the robustness of the observed relationships across a range of different analysis choices, with decision nodes focusing on the choice of CPP metric (build-up rate, amplitude, or peak amplitude) and pooling method in statistical analysis (trial-wise or bin-wise). Overall, the study promises to offer a fresh perspective – both methodologically and theoretically – on how CPP relates to perceptual decision-making.

 

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/vwmzh
 
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:
 

• Advances in Cognitive Psychology
• Brain and Neuroscience Advances
• Cortex
• Imaging Neuroscience
• In&Vertebrates
• Journal of Cognition
• NeuroImage: Reports
• Peer Community Journal
• PeerJ
• Royal Society Open Science
• Studia Psychologica

 

 

Liu, Y., Yan, C., & Chuan-Peng, H. (2025). Is CPP an ERP marker of evidence accumulation in perceptual decision-making? A multiverse study. In principle acceptance of Version 4 by Peer Community in Registered Reports. https://osf.io/vwmzh