Working memory, not processing speed, mediates fluid intelligence deficits in ADHD
In 142 young adults, the link between ADHD symptoms and fluid intelligence runs through working memory. Processing speed does not carry it.
The idea
People with more ADHD symptoms often score lower on fluid intelligence. This study asks which measure carries that gap. In 142 young adults from the general population, total symptom scores and hyperactive symptom scores were negatively correlated with fluid intelligence, and working memory fully mediated the association. Inattentive symptoms were not associated with fluid intelligence.
The approach
The same people completed working-memory tasks, processing-speed tasks, fluid-intelligence tasks, and an ADHD symptom questionnaire. The result is a mediation test: the symptom-intelligence path is accounted for by working memory. Processing speed was not associated with ADHD symptoms at all, and it was not a unique predictor of fluid intelligence. The paper draws the practical implication toward working-memory training, and toward treating hyperactive and inattentive profiles as different neuropsychological pictures.
- 142 young adults from the general population
- Total and hyperactive symptoms correlate with lower fluid intelligence
- Working memory fully mediates that association
- Inattentive symptoms are not associated with fluid intelligence
- Processing speed does not carry the effect
- Brydges, Ozolnieks, and Roberts. Journal of Neuropsychology, 11(3), 362-377
The paper: www.emc-lab.org .