Mean intake for the preshift days (trials 1–10) and postshift days (trials 11–14) for Lewis (left panel) and Fischer (right panel) rats. In both strains, half of the rats were given 5 min access to 0.1 M sucrose throughout the study (unshifted, squares). The other half of the rats were given 5 min access to 1.0 M sucrose for 10 trials and were then downshifted to 0.1 M sucrose across trials 11–14 (shifted, circles). On trial 12, half of the rats from each shift condition were pretreated with saline (closed symbols) and the other half with chlordiazepoxide (CDP, open symbols).