The current study assessed stereopsis and action performed in depth under monocular and binocular viewing conditions in WS and typically developing (TD) non-verbal ability matched control participants. If ocular deficits are the root of poor depth perception in WS then participants should perform more poorly on binocular assessment, but inline with the TD group on monocular tasks. TD individuals that have poor binocular vision (such as strabismus), can still function well by relying on monocular cues (Helveston, 2010, Henson and Williams, 1980 and Von Noorden and Campos, 1996). If a dorsal stream deficit is the root of atypical depth perception in WS, deficits should be seen when acting in depth and perceiving depth binocularly, with little difference between performing actions under monocular or binocular viewing conditions. However, based on the trends reported from our questionnaire, we predict deficits in processing of monocular and binocular depth cues for both perception and action. This would suggest an additional general perceptual deficit in implicit understanding of monocular cues to depth, which necessarily extends to action.