CONCEPT

Neuronal Recycling

Dehaene’s theory that cultural learning—reading, mathematics, music—colonizes cortical regions that evolved for other purposes, constrained and enabled by the brain’s pre-existing architecture; a principle that explains both extraordinary human plasticity and the specific ways that competence built through practice can atrophy when outsourced.

Writing was invented only a few thousand years ago, far too recently for evolution to have built any dedicated neural machinery for it. The brain that learns to read is, genetically, the brain of a hunter-gatherer who never saw a letter. And yet in every literate human, regardless of language or script, the recognition of written words depends on a small, remarkably consistent region of the left ventral visual cortex that Dehaene and Laurent Cohen named the visual word form area—the brain’s “letterbox.” How can a brain with no evolved provision for reading possess a specialized reading region? Dehaene’s answer is neuronal recycling: the brain does not invent a new region for reading, it recycles an existing one. The letterbox evolved to recognize objects and faces, extracting the small visual features—curves, junctions, line terminations—that distinguish one thing from another. Reading hijacks this machinery. Crucially, writing systems across the world’s cultures are statistically biased

Keep reading with YOU ON AI