Stimulus magnitude estimation

Recall that Stevens' power law is not about detection thresholds, but is instead about the perceived magnitude of a stimulus. For example, one plate might feel twice as hot as another. In this case, subjects are asked to estimate the relative difference in magnitude between stimuli. Over a sufficient number of trials, the exponent of Stevens' power law (2.1) can be estimated by choosing a value for $x$ (the exponent) that minimizes the least-squares error (recall from Section 9.1).