Table 1. Experimental Subjects.

Subject	Age	Weight (kg)	Lifetime cocaine intake (mg/kg)	Experiments participated in
R-1374	13	11.2	1385	Experiments 2, 3, and 4
R-1375	13	10.1	635	Experiments 2 and 4
R-1377	12	9.7	1089	Experiments 3 and 4
R-1381	13	10.4	922	Experiments 2, 3, and 4
R-1424	11	10.1	0	Experiment 2
R-1661	13	9.0	0	Experiment 2
R-1662	13	7.2	0	Experiment 2
R-1663	13	8.2	0	Experiment 2