Brown University, Department of Cognitive, Linguistic & Psychological Sciences
Perception is commonly thought of as a process solving the inverse geometry problem: given the sensory input and prior knowledge about the world, the brain derives an accurate representation of physical reality. This naïve realist view is also the hallmark of the dual-visual-stream theory of perception and action: when perception is distorted because of ambiguous or conflicting visual cues our actions seem to be accurate. In this talk I argue that both perception and action are based on the same 3D representation, which in general does not mirror physical reality. Instead of being distinct I propose that perception and action form a coordinated system: Perception informs action about the state of the world and, in turn, action shapes perception by signaling when it is faulty. This integrated approach is quite distinct from most investigations on perception and motor control. On the one hand, while motor errors have been studied extensively in the sensorimotor adaptation field, they have overlooked how perception actually affects these errors. Indeed, I’ll show that the visual space is systematically distorted and that these distortions clearly surface in our actions. Remarkably the arising motor errors produce motor adjustments on a trial-by-trial basis. On the other hand, studies exploring alterations of visual percepts following visuomotor interactions have neglected the causal role of error signals. Here, I will also show that persisting sensory errors signals cause a remarkable modification of space perception. In summary, contrary to the naïve realist view and the dual-visual-stream theory, my approach regards perception and action as two sides of the same coin expressing a currency which is not metric accuracy.