Assessing the reliability of an online behavioural laterality battery: A pre-registered study.

Studies of cerebral lateralization often involve participants completing a series of perceptual tasks under laboratory conditions. This has constrained the number of participants recruited in such studies. Online testing can allow for much larger sample sizes but limits the amount of experimental control that is feasible. Here we considered whether online testing could give valid and reliable results on four tasks: a rhyme decision visual half-field task, a dichotic listening task, a chimeric faces task, and a finger tapping task. We recruited 392 participants, oversampling left-handers, who completed the battery twice. Three of the tasks showed evidence of both validity and reliability, insofar as they showed hemispheric advantages in the expected direction and test-retest reliability of at least r = .75. The reliability of the rhyme decision task was less satisfactory (r = .62). We also confirmed a prediction that extreme left-handers were more likely to depart from typical lateralization. Lateralization across the two language tasks (dichotic listening and rhyme judgement) was weakly correlated, but unrelated to lateralization on the chimeric faces task. We conclude that three of the tasks, dichotic listening, chimeric faces and finger tapping, show considerable promise for online evaluation of cerebral lateralization.