Fig. 7. The range of reinforcer rates for the studies indicated (based on median low and high reinforcer rates from the study).

Studies with pigeons are shown below the horizontal line; those with rats are above the line. The solid dot on each line indicates the median value of R_o for the corresponding data set. All reinforcer rates are obtained values except for those from Catania and Reynolds (1968) and Zeiler (1999), which are scheduled values.