1. A method for modifying a controllable stimulus generated by a perceptual device in communication with a human user, the method comprising: generating an input signal to the perceptual device, the perceptual device sending a stimulus to the human user, the stimulus defined at least in part by a parameter, the parameter comprising a value; receiving an output signal from the human user, the output signal based at least in part on a perception of the stimulus by the human user; determining a difference between the input signal and the output signal; constructing a perceptual model based at least in part on the difference; performing a plurality of independent algorithms on the perceptual model, wherein the plurality of independent algorithms provide at least one parameter value; and suggesting a new value for the parameter based at least in part on the at least one parameter value provided by the plurality of independent algorithms.