The cardinality principle (CP) is a key concept in numerical cognition, which children typically acquire by the age of five. This is the understanding that each number in a counted sequence refers to a specific set of items, and that the final number represents the total size of the set. Here, Ivanova and colleagues (2024) propose an experiment to study the changes in neural activity that accompany the acquisition of this concept, focusing on activity within the parietal lobes as measured by functional near-infrared spectroscopy (fNIRS).

 

Typically-developing children aged from 2 years 9 months to 4 years 9 months will be assessed for their ability to give a specific number of balls from a pile: those who can give five or more correctly will be classified as CP-knowers, and those who can only give lower set sizes will be classified as subset-knowers. All children will then perform an auditory number word adaptation task while undergoing fNIRS. The adaptation task involves hearing the number word ‘two’ repeated, interspersed with deviant number words (‘four’ or ‘eight’) or a non-number word (‘rin’). The experimental hypotheses are that left parietal activations and bilateral parietal functional connectivity will be differentially greater for number than non-number deviants amongst CP-knowers than amongst subset-knowers. Each hypothesis will be tested by sequential Bayes factor analysis, with a minimum of 25 and a maximum of 46 participants per group, providing high sensitivity to detect a smallest effect size of d = .35. This study aims to provide insights into the neural underpinnings of the CP, informing theoretical models of symbolic knowledge acquisition.

The study plan was refined over four rounds of review, with input from two external reviewers, after which the recommender judged that the Stage 1 manuscript met the criteria for in-principle acceptance (IPA).

 

Level of bias control achieved: Level 4. At least some of the data/evidence that will be used to answer the research question already exists and is accessible in principle to the authors (e.g. residing in a public database or with a colleague) but the authors certify that they have not yet accessed any part of that data/evidence.
 
List of eligible PCI RR-friendly Journals:
 

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

 

 

Ivanova, E., Joanisse, M., Ansari, D., & Soltanlou, M. (2024). The origin of symbolic numerical knowledge in early development – an fNIRS Registered Report. In principle acceptance of Version 7 by Peer Community in Registered Reports. https://osf.io/gzpk5