Sensorimotor contingency

The sensorimotor contingency theory of perception holds that to perceive is not to construct an internal representation of the external world, but to master the regularities that govern how sensory stimulation changes as the organism moves. Developed by philosophers Alva Noë and Kevin O'Regan, the theory draws on the enactivist tradition of Francisco Varela and Evan Thompson to argue that perception is a form of embodied skill — a kind of practical knowledge of how one's movements affect one's sensory inputs.

The central claim is that the quality of a perceptual experience is determined not by the intrinsic properties of the sensory stimulus but by the sensorimotor contingencies associated with it. To see a red sphere is not to activate a 'red sphere' representation in the brain but to possess the practical knowledge that if you move your eyes toward the object, the red patch will expand in a characteristic way; if you close one eye, the binocular disparity will change; if you reach for it, your hand will encounter resistance at a certain distance. These regularities — the laws of sensorimotor contingency — constitute what it is to perceive the object as a red sphere.

The Rejection of Neural Internalism

The sensorimotor contingency theory stands in direct opposition to what Noë calls 'neural internalism': the view that perceptual experience is determined entirely by neural processes inside the brain. On the sensorimotor view, the brain is necessary but not sufficient for perception. What matters is the whole loop of organism-environment interaction — the sensorimotor coupling that the brain participates in but does not constitute.

This has been supported by empirical findings in sensory substitution. When blind subjects are fitted with devices that translate visual information into tactile vibrations on the skin, they do not merely receive tactile patterns. After sufficient training, they report visual-like experiences — not because the tactile patterns resemble visual representations, but because the subjects have learned the sensorimotor contingencies associated with the device. They know how the tactile pattern will change as they move, and this practical knowledge constitutes a form of spatial perception.

Objections and Responses

The theory has been criticized for being unable to account for phenomena that do not seem to depend on movement: afterimages, hallucinations, mental imagery. The response is that even these phenomena involve implicit sensorimotor knowledge. An afterimage persists when the eyes are closed because the visual system continues to operate according to sensorimotor regularities even in the absence of current stimulation. Mental imagery is the activation of sensorimotor knowledge in the absence of the corresponding environmental condition.

A deeper objection concerns the nature of the 'mastery' that sensorimotor contingency theory posits. Is mastery a form of knowledge-that (propositional knowledge of the regularities) or knowledge-how (practical skill)? Noë argues for the latter: the perceiver does not know propositions about sensorimotor contingencies but possesses a practical capacity to engage with them. This connects the theory to the broader enactivist claim that cognition is not propositional but procedural.