YOUR BRAIN FILES \u00bd AND 7 ON THE SAME INVISIBLE RULER<\/p>\n
When you see the fraction \u00bc, your eyes meet a four. Your brain, according to a new brain-imaging study, treats it as something close to zero. In a region at the top of the brain, fractions and whole numbers appear to be placed along one shared line, arranged by how big they are and not by what they look like.<\/p>\n
The finding comes from 20 adults. All were native French speakers, and the study used functional MRI, which tracks blood flow as an indirect measure of brain activity. The result is a pattern in group averages, not a recording of individual neurons, and it does not show why fractions are harder to learn. It was published in PLOS Biology on 22 October 2026.<\/p>\n
## WHAT WAS FOUND<\/p>\n
The paper, \u201cA cortical semantic map integrates fractions and integers in the human brain,\u201d is by Daniela Val\u00e9rio and Stanislas Dehaene of the INSERM-CEA Cognitive Neuroimaging Unit (UNICOG) in France. Dehaene has spent decades studying how the brain represents numbers.<\/p>\n
Volunteers lay in an MRI scanner and viewed a mix of fractions and whole numbers. For each one, they judged whether it was larger or smaller than the number shown before it. The scan focused on the anterior inferior parietal cortex, a region already known to be involved in number processing.<\/p>\n
In that region, activity formed an organised pattern that resembles a number line. Small values produced one kind of activity pattern, shown in reddish tones in the published averages, and larger values produced another, shown in bluish tones. Whole numbers and fractions were placed on the same line, by magnitude, not in separate systems.<\/p>\n