Skilled actions are commonly assumed to be controlled by precise internal schemas or cognitive maps. We challenge these ideas in the context of skilled typing, where prominent theories assume that typing is controlled by a well-learned cognitive map that plans finger movements without feedback. In two experiments, we demonstrate that online physical interaction with the keyboard critically mediates typing skill. Typists performed single-word and paragraph typing tasks on a regular keyboard, a laser-projection keyboard, and two deconstructed keyboards, made by removing successive layers of a regular keyboard. Averaged over the laser and deconstructed keyboards, response times for the first keystroke increased by 37%, the interval between keystrokes increased by 120%, and error rate increased by 177%, relative to those of the regular keyboard. A schema view predicts no influence of external motor feedback, because actions could be planned internally with high precision. We argue that the expert knowledge mediating action control emerges during online interaction with the physical environment.
