Does degree of asymmetry relate to performance? An investigation of word recognition and reading in consistent and mixed handers.

Is it advantageous to be strongly lateralized? The current study investigated this question by examining the relationship between visual field asymmetries for lexical tasks and reading performance in a sample of 200 young adults. Larger visual field asymmetries were associated with better reading performance, but this relationship was obtained primarily in those with strong and consistent hand preferences. Among mixed handers, variation in visual field asymmetry accounted for little or no variance in reading skill. In addition, correlations between visual field asymmetry and reading performance were observed for word recognition tasks, but not for tasks requiring controlled semantic retrieval. The results are consistent with the idea that consistent and mixed handers may represent differing neurobehavioral populations. Because greater lateralization was associated with better reading skill only for consistent handers, reduced behavioral asymmetry cannot be assumed to be a risk factor for reading dysfunction in the population as a whole.