Figure 4.

Shifts of the reward mountain. The contour graph for the long-duration (1 s) train is shown in the lower left. For comparison the contour graph for the short-duration (0.25 s) train is shown twice, in the upper left and lower right. The P_e parameter determines the location along the price axis, whereas the F_hm parameter determines the location of the mountain along the pulse-frequency axis. The vertical blue line represents the estimate of P_e, and the surrounding band represents the corresponding 95% confidence interval. The horizontal red line represents the estimate of F_hm, and the surrounding band represents the corresponding 95% confidence interval. The bar graph shows the mean shifts in the location parameters due to the increase in train duration from 0.25 to 1 s along with the associated 95% confidence intervals. ^*Indicates that the 95% confidence interval does not include zero.