Table 1. Average food reinforcers earned from each alternative across the last five sessions of Phases 1–3 in Experiment 1.

	50% vs. 50%		25% vs. 50%		12.5% vs. 50%
Subject	Disc. alt.	Nondisc. alt.	Disc. alt.	Nondisc. alt.	Disc. alt.	Nondisc. alt.
20	23.5	12.5	12.0	12.1	4.9	8.5
135	24.0	12.0	11.4	13.3	3.7	13.2
245	20.1	15.9	11.3	13.4	4.4	10.4
254	23.6	12.4	10.2	15.6	4.4	10.6
257	23.7	12.3	11.9	12.2	5.0	8.2
1056	22.6	13.4	11.0	14.1	3.8	13.0
4074	18.5	17.5	9.8	16.4	4.0	12.1
19227	22.5	13.5	11.0	14.1	4.2	11.2
19229	23.9	12.1	12.0	12.0	4.8	8.7
22642	23.9	12.1	11.9	12.2	4.9	8.3
Mean	22.63	13.37	11.23	13.54	4.40	10.42
Proportion	0.629	0.371	0.453	0.547	0.297	0.703