Averaged control performance of individual monkeys under the concurrent schedule of i.v. self-administration and food delivery during sessions in which i.v. saline was available for self-administration in all three components (n = 15-20 sessions) Data show mean values (with 95% confidence limits in parentheses) in individual monkeys for each 30-min component (n = 15-20).
Component | Mm 211 | Mm 258 | Mm 331 | Mm 263 | ||
|---|---|---|---|---|---|---|
| Percentage of injection-lever responses | ||||||
| I | 2 (2) | 6 (6) | 6 (6) | 3 (4) | ||
| II | 1 (2) | 2 (2) | 13 (14) | 1 (1) | ||
| III | 1 (1) | 20 (14) | 21 (14) | 2 (3) | ||
| Number of food deliveries | ||||||
| I | 27 (2) | 31 (2) | 26 (2) | 25 (3) | ||
| II | 28 (2) | 32 (1) | 23 (5) | 25 (4) | ||
| III | 25 (3) | 26 (5) | 20 (5) | 23 (3) | ||
| Number of i.v. saline injections | ||||||
| I | 2 (1) | 2 (2) | 3 (2) | 1 (1) | ||
| II | 1 (1) | 2 (1) | 4 (3) | 1 (1) | ||
| III | 1 (1) | 5 (3) | 5 (3) | 1 (1) | ||
| Response rate (responses per second) | ||||||
| I | 1.8 (0.3) | 3.5 (0.4) | 2.0 (0.3) | 1.7 (0.4) | ||
| II | 2.0 (0.3) | 3.7 (0.3) | 1.8 (0.5) | 1.7 (0.3) | ||
| III | 1.6 (0.4) | 2.9 (0.6) | 1.5 (0.5) | 1.3 (0.4) | ||