Hand movements reflect competitive processing in numerical cognition.

Traditional models of numerical cognition are based on the computer-based metaphor of cognition that assumes numerical judgments are stage-based and independent of bodily effectors. However, recent studies have indicated that the traditional metaphor may be inadequate for describing the processes involved in numerical decisions. In the present study, I provide further evidence that number processing proceeds in a continuous, competitive manner tightly coupled with feedback from the motor system. Forty-five adult participants' hand movements were recorded as they used a computer mouse to choose the correct parity (odd/even) for single-digit numerals. Distributional analyses of these hand movements indicated that responses resulted from competition between parallel and partially active mental representations rather than occurring in discrete stages.