# Numerical format integration in primary school children examined with frequency-tagged electroencephalography

## TL;DR

This study explores how children process different ways of representing numbers, like digits and words, using brain activity measurements.

## Contribution

The study introduces a novel EEG-based method to examine numerical format integration in children under rapid presentation conditions.

## Key findings

- Children showed stronger neural responses when integrating dots with number words compared to other formats.
- Numerical magnitude information is automatically extracted regardless of format under rapid presentation.
- Deviant responses were observed only in the experimental condition with a magnitude rule.

## Abstract

Mastering the relationship between different numerical formats (i.e., digits, number words, and non-symbolic quantities) is an important foundational skill for later math competencies. However, the neurocognitive mechanisms of this relationship remain poorly understood in children. Consequently, the current study examines the integration between digits, number words, and dots in a sample of 34 primary school children (aged 7 to 14 years) with an electroencephalography paradigm tagging the frequency of stimulus presentation. In an oddball paradigm, we presented children with mixed notation sequences (i.e., dots – words, digits – dots, words – digits) at a rate of 166 ms per stimulus while manipulating the magnitude of the deviant numbers in an experimental (rule = standards < 5, deviants > 5) and control conditions (no rule). We observed deviant responses in the experimental but not in the control condition, with the strongest responses for dots – words, followed by words – digits and finally, digits – dots. These findings suggest that, in children, numerical magnitude information is automatically extracted irrespective of the format at least under implicit and rapid presentation conditions.

The online version contains supplementary material available at 10.1038/s41598-025-11281-7.