Mentor: Dr. Paul Neuman
Six pigeons will be exposed to concurrent-chain schedules to examine the effect of history on choice patterns. The initial links will be fixed-interval (FI) 15s, 30s or 60s schedules, depending on the pigeon, and the terminal-links will be 5-valued variable-ratio (VR) schedules of reinforcement, varying by condition. During baseline, terminal link requirements will be identical VR 60 schedules (equal alternative conditions) for both of the red and white keys. Preferences will be established by making the response requirements on the red key alternative larger (VR 90) or smaller (VR 30), depending on the condition (unequal alternative conditions). After preferences are established, all subjects will be exposed to forced choice sessions with the same equal terminal-link response requirements as during baseline before a return to baseline. The amount that preferences persist will be assessed with returns to baseline when terminal-link response requirements are equal.