The location of the reward mountain along the price axis.

The “ Drg” and “ Veh” columns list the estimated values that the parameter would have attained in the drug and vehicle conditions, respectively, had frequency following been perfect. The “diff” column shows the differences between the estimates for the drug and vehicle conditions, whereas the “diff Lo” and “diff Hi” columns designate the lower and upper bounds of the 95% confidence interval surrounding these differences. The ⋆ character in the “excl 0” column indicates that zero falls outside the 95% confidence interval surrounding the estimates in the“diff” column. Differences so designated meet our criterion for statistical reliability. The rightmost column lists the proportional drug-induced change in the value of corresponding to the values in the “diff” column. ().