A system and method may adjust the evaluation of input signals from an input device used by a game player, based on performance or motor acuity. A relationship or mapping between computer input device input and movement within a virtual environment may be adjusted based on the performance metric. An embodiment may measure or calculate a performance metric or motor acuity in a person playing a computer game by determining, for different target types, speed of the player and one of precision, accuracy and variability of the player; and determining motor acuity based on the relationship between speed of the player and the precision, accuracy or variability. The calculation may be using a statistical analysis; and may be by creating a best-fit line in a comparison of speed and variability; and transforming the best-fit line to a curve in a comparison of player speed and player precision.