Common coding theory

Common coding theory is a cognitive psychology theory describing how perceptual representations (e.g. of things we can see and hear) and motor representations (e.g. of hand actions) are linked. The theory claims that there is a shared representation (a common code) for both perception and action. More important, seeing an event activates the action associated with that event, and performing an action activates the associated perceptual event. The idea of direct perception-action links originates in the work of the American psychologist William James and more recently, American neurophysiologist and Nobel prize winner Roger Sperry. Sperry argued that the perception–action cycle is the fundamental logic of the nervous system. Perception and action processes are functionally intertwined: perception is a means to action and action is a means to perception. Indeed, the vertebrate brain has evolved for governing motor activity with the basic function to transform sensory patterns into patterns of motor coordination. The classical approach to cognition is a 'sandwich' model which assumes three stages of information processing: perception, cognition and then action. In this model, perception and action do not interact directly, instead cognitive processing is needed to convert perceptual representations into action. For example, this might require creating arbitrary linkages (mapping between sensory and motor codes). In contrast, the common coding account claims that perception and action are directly linked by a common computational code. This theory, put forward by Wolfgang Prinz and his colleagues from the Max Planck Institute for Human Cognitive and Brain Sciences, claims parity between perception and action. Its core assumption is that actions are coded in terms of the perceivable effects (i.e., the distal perceptual events) they should generate. This theory also states that perception of an action should activate action representations to the degree that the perceived and the represented action are similar.