The Double-Deficit Hypothesis: Wolf's Most Influential Paper

The 1999 paper that showed phonology and naming speed are separable deficits — and that children with both struggle most.

Maryanne Wolf & Patricia Bowers

Sep 1, 1999

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Wolf and Bowers’ 1999 paper — her most influential — showed that naming speed is a second source of reading failure, separable from phonology. Children with both deficits struggle most. Wolf, explaining it in her own words:

There are these kids who have single deficits in phoneme awareness, single deficits in naming speed without phoneme, and then double-deficit kids who have both. The kids who have both reading fluency and comprehension issues have different reasons for reading failure than the kids who have only phoneme awareness issues.
— Maryanne Wolf, Children of the Code interview

Read the original 1999 paper (free PDF).

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