To examine possible differences in RT during the 1-hour operant sessions, average median response latencies were calculated in 5-trial blocks up to 40 trials. We selected 40 trials as the upper limit, as there were some subjects that did not complete more than 40 trials and would therefore have been excluded from the analysis. A mixed Experiment (1 or 2) × Sex × Alcohol Preference (High or Low) × Block (1 to 8) ANOVA was performed on these data. Main effects of Experiment F(1,60) = 33.73, p < 0.001, Alcohol Preference F(1,60) = 8.59, p = 0.005, and Block F(4.8,288) = 40.30, p < 0.001 were detected, but Sex was not (p = 0.62). No interactions with Sex were found (ps > 0.16), but interactions of Block × Experiment F(4.8,288) = 2.36, p = 0.043 and Block × Alcohol Preference F(4.8,288) = 7.33, p < 0.001 were detected. In experiment 1, a main effect of Block and an interaction of Block × Line F(4.0,124.8) > 3.97, ps < 0.005 were detected, therefore HAP2 and LAP2 were stratified. Simple main effects
