1. A method for modifying the effect of an operator controlled input device on an interactive device to encourage the self-regulation of at least one physiological activity by the operator, the operator controlled input device utilizing one or more position reference signal elements to provide motion and/or position-sensing capability relative to the one or more position reference signal elements, the interactive device comprising a display area that depicts images and an apparatus for receiving at least one input from the operator controlled input device to thus permit the operator to control and interact with at least some of the depicted images, the method for modifying comprising the steps of: measuring at least one physiological activity of the operator to obtain at least one physiological signal having a value indicative of the level of the at least one physiological activity; and modifying the motion and/or position sensing capability of the operator controlled input device by modifying one or more position reference signal elements in response to (a) changes in the measured at least one physiological signal and/or (b) differences between the measured at least one physiological signal and a corresponding predetermined desired physiological signal level, thereby modifying the ability of the operator to control and interact with at least some of the depicted images, wherein the one or more position reference signal elements comprise a plurality of LEDs, two of which emit light at any particular time; wherein the operator controlled input device comprises a light detector for detecting light emitted from the LEDs, and wherein the step of modifying one or more position reference signal elements comprises the step of changing which two of the LEDs are emitting light at any particular time.