Brain-Computer Interfaces and the Translation of Thought into Action

A brain-computer interface (BCI) designed to restore motor function detects neural activity related to intended movement and thereby enables a person to control an external device, for example, a robotic limb, or even their own body. It would seem legitimate, therefore, to describe a BCI as a system that translates thought into action. This paper argues that present BCI-mediated behavior fails to meet the conditions of intentional physical action as proposed by causal and non-causal theories of action. First, according to the causal theory of action physical actions are bodily movements that are causally related to a person’s intentions. It can be argued, however, that the proximate cause of action in present BCI-mediated behavior is not the person’s intention, and that the behavior fails to meet the conditions of reliability, sensitivity and difference-making. Second, BCI-mediated behavior can be accommodated by a Volitionist account of action if we can equate imagining movement with trying to move. The argument presented is that the novelty, and limited functionality and sensory feedback of present BCIs challenges this equation.