Fig. 10.

(a) Circles show empirically derived (data from DEO) estimates of the identity response function for four faces, along with fits from the Naka–Rushton (NR) equation (solid lines). The boxed legend below the figure indicates the best fitting parameters for each individual NR fit to the data (R_max, b, and n); note the shallow sigmoidal shape of the response function as indicated by values of n consistently exceeding 1. The right part of the figure shows these response function re-plotted on x-axes that have been scaled by one of the four parameters indicated. Scaling by the estimated minimum threshold brings the curves into close registration.