ABSTRACT
Cognitive approaches to psychophysics give new meaning to variables such as the mean and variance of perceived stimulus magnitude. The aspect of sensory psychophysics reformulated in this chapter is the source of response variability. The Sensory Aggregate Model attributes this variability to the ensemble of neurons involved in coding a single stimulus. Not all the neurons comprising this set are firing at the same rate, and therefore the subject has some leeway (conscious or unconscious) in selecting the neuron or subset of neurons sampled on a given trial. This process is repeated over trials and thereby generates the response variability observed in the psychophysics laboratory.
