Figure 9: The upper panel relates the average slopes of resistance functions obtained by Nevin et al. (1990 -- see Figure 3) to the predictions of Equations 17 and 18. Error bars show the standard errors of the mean obtained slopes. The lower panel shows the slope of the extinction curve predicted by Equation 17 as a function of reinforcer rate during training, with parameters a and d set at the values estimated by fits to the data of Nevin et al. (1990).