An increase in brain activity known as the "readiness potential" (RP) can be seen over central scalp locations in the seconds leading up to a volitionally timed movement. This activity precedes awareness of the ensuing movement by as much as two seconds and has been hypothesized to reflect preconscious planning and/or preparation of the movement. Using a novel experimental design, we teased apart the relative contribution of motor-related and non-motor-related processes to the RP. The results of our experiment reveal that robust RPs occured in the absence of movement and that motor-related processes did not significantly modulate the RP. This suggests that the RP measured here is unlikely to reflect preconscious motor planning or preparation of an ensuing movement, and instead may reflect decision-related or anticipatory processes that are non-motoric in nature.