A traditional model of visual processing for perception and action proposes that the two tasks rely on different visual representations. This model explains the weak effect of visual illusions like the Müller-Lyer illuson on performance in grasping tasks.⇒
Foster et al. challenge the methodology used in a previous study by Dewar and Carey which supports the perception and action model of visual processing due to Goodale and Milner.
They do that by changing the closed visual-action loop in Dewar and Carey's study into an open one by removing visual feedback at motion onset. The result is that the effect of the illusion is there for grasping (which it wasn't in the closed-loop condition) but not (as strongly) for manual object size estimation.
Foster et al. argue that this suggests that the effect found in Dewar and Carey's study is due to continuous visual feedback.⇒