Acquisition and extinction under periodic reinforcement

This study reexamined the processes of acquisition and extinction under per iodic reinforcement. During the first phase of the experiment, pigeons were exposed to a fixed-interval schedule either 40 or 80 s long. During the se cond phase, each session started with the fixed-interval schedule but chang ed to extinction at an unpredictable moment. The results showed that during phase 1 the curve for the average rate of pecking along the interval rotat ed across sessions, that is, the rate immediately after food decreased, whe reas the rate at the end of the interval increased. The initial and termina l rates approached their steady state at different speeds. During the extin ction trials of phase 2, behavior was characterized by pause-peck oscillati ons with a period slightly longer than the fixed-interval duration. These f indings concerning acquisition and extinction under periodic reinforcement were then compared with the predictions of some current theories of timing. (C) 1998 Elsevier Science B.V. All rights reserved.