Table 1.

Experiment 1

Stage I	Stage II	Stage III	Devalue	Test
S1: R1–O1, R2–	S1: R2– O2, R1–	S1: R1 – O1, R2 – O2	O1 or O2	S1: R1 vs. R2
S2: R2–O1, R1–	S2: R1–O2, R2–	S2: R1 – O2, R2 – O1		S2: R1 vs. R2

Design of Experiments 1 and 2. Experiment 1 incorporated each stage, Experiment 2 incorporated Stage III, Devalue, and Test stages only. R1 and R2 were the instrumental responses left lever press and right lever press, S1 and S2 were the discriminative stimuli tone and clicker, O1 and O2 were the two outcomes, sucrose and pellets.