Figure 2.

Mean magazine responding over 4-session blocks of training on the ambiguous cue occasion setting task for groups receiving differential (Gp Differential) and nondifferential (Gp Non Differential) reinforcement in Experiment 2. Data are shown separately in the pre stimulus periods (Pre, Pre A), as well as to the target stimuli (X, Y) in the presence and absence of the feature stimulus (A). + and * denote reinforcement by different outcomes and – indicates nonreinforcement.