Figure 3.

Proportion of baseline scores for immediate reduction (open symbols, left hand bars) and gradual reduction (filled symbol, right hand bars). Bars represent group averages; symbols represent individual rats. Group sizes are at least nine across all groups. (A) First day of each reduction. Infusions earned on the first day are divided by the average infusions earned over the last 3 days of baseline. Significantly fewer infusions were earned for the gradual reduction method at the 1.875 µg/kg/infusion dose (t ₁₉ = 4.696, p < .05). (B) Stable behavior. Infusions earned over the last 3 days of each reduction are divided by infusions earned on the last 3 days before initial reduction for the gradual reduction group. Scores for the immediate reduction groups are calculated in the same way using the three sessions of comparable experience at each dose.