RAPID DETERMINATIONS OF PREFERENCE IN MULTIPLE CONCURRENT‐CHAIN SCHEDULES

Abstract

With concurrent chains arranged for a pigeon's key pecks, pecks on two concurrently available initial‐link keys (left and right) respectively produce separately operating terminal links (A and B). Preferences for terminal link A over terminal link B are usually calculated as deviations of relative initial‐link response rates (left divided by total pecks) from those during baseline conditions, when A equals B. Baseline preferences, however, are often variable and typically are determined indirectly (e.g., with unequal A and B, reversing left‐right assignments of A and B over sessions and estimating the baseline from differences between the relative rates generated). Multiple concurrent‐chain schedules, with components each consisting of a pair of concurrent chains, speed the determination of preferences by arranging A and B and their reversal within sessions. In two experiments illustrating the feasibility of this procedure, one component operated with circles projected on initial‐link keys and the other with pluses; when left and right initial‐link pecks respectively produced terminal links A and B in one component, they produced B and A in the other. Even as the baselines fluctuated, preference was observable within sessions as the difference between relative initial‐link response rates in the two components. The first experiment demonstrated the rapid development of preferences when terminal links A and B consisted of fixed‐interval 15‐s and 30‐s schedules. The second demonstrated the sensitivity of the procedure to preference for a fixed‐interval 30‐s schedule operating for pecks on either of two keys (free choice) over its operating for pecks on only a single key (forced choice).