Magnocellular Pathway and Reading Rate: An Equivalence Test Analysis

Previous research has revealed conflicting results with regard to the role of the magnocellular visual system in reading and dyslexia. In order to investigate this further, the present study examined the relationship between performance on two magnocellular tasks (temporal gap detection and coherent motion), reading rate (oral and silent), and rapid letter naming (serial and isolated naming). Results showed that in a sample of 83 college students magnocellular performance was not significantly correlated with reading rate or rapid letter naming. Equivalence test analyses showed all correlations between magnocellular performance and reading rate or rapid letter naming to be within the bounds of -0.3 to 0.3. This provides evidence against the idea that having low magnocellular performance will result in poor reading ability. In opposition to the magnocellular deficit theory of dyslexia, these results suggest that a magnocellular deficit is not causally related to reading rate.