Definition
Exafference
Exafference is sensory stimulation that originates from external sources in the environment, as opposed to reafference, which is generated by an organism’s own actions. It is the “surprise” signal that the brain processes when incoming sensory information does not match the internal prediction (corollary discharge) intended to cancel out self-generated feedback. This resulting perceptual signal signifies a genuine change in the external world, forcing an update to the organism’s mental model in a way that is analogous to violating the “nothing changes” assumption of the frame problem.