Joo, Donnelly & Yeatman – The causal relationship between dyslexia and motion perception reconsidered

Joo SJ, Donnelly PM & Yeatman JD. The causal relationship between dyslexia and motion perception reconsidered. Nature Scientific Reports, 2017.

It is well established that visual sensitivity to motion is correlated with reading skills. Yet, the causal
relationship between motion sensitivity and reading skills has been debated for more than thirty
years. One hypothesis posits that dyslexia is caused by deficits in the motion processing pathway. An
alternative hypothesis explains the motion processing deficit observed in dyslexia as the consequence
of a lack, or poor quality, of reading experience. Here we used an intensive reading intervention
program to test the causal relationship between learning to read and motion processing in children.
Our data show that, while the reading intervention enhanced reading abilities, learning to read did
not affect motion sensitivity. Motion sensitivity remained stable over the course of the intervention.
Furthermore, the motion sensitivity deficit did not negatively impact the learning process. Children
with poor motion sensitivity showed the same improvement in reading skills as children with typical
motion sensitivity. Our findings call into question the view that motion processing deficits are due to
poor reading experience. We propose that the correlation between the two measures arises from other
common mechanisms, or that motion processing deficits are among a collection of correlated risk
factors for reading difficulties.