Rapid acquisition in concurrent chains: effects of initial-link duration.
Pigeons were trained in a concurrent chains procedure in which the terminal-link schedules in each session were either fixed-interval (FI) 10s FI 20s or FI 20s FI 10s, as determined by a pseudorandom binary series. The initial-link was a variable-interval (VI) 10-s schedule. Training continued until initial-link response allocation stabilized about midway through each session and was sensitive to the terminal-link immediacy ratio in that session. The initial-link schedule was then varied across sessions between VI 0.01 s and VI 30s according to an ascending and descending sequence. Initial-link response allocation was a bitonic function over the full range of durations. Preference for the FI 10-s terminal-link at first increased as programmed initial-link duration varied from 0.01 to 7.5s, and then decreased as initial-link duration increased to 30s. The bitonic function poses a potential challenge for existing models for steady-state choice, such as delay-reduction theory (DRT) [Fantino, E., 1969. Choice and rate of reinforcement. J. Exp. Anal. Behav. 12, 723-730], which predict a monotonic function. However, an extension of Grace and McLean's [Grace, R.C., McLean, A.P., 2006. Rapid acquisition in concurrent chains: evidence for a decision model. J. Exp. Anal. Behav. 85, 181-202] decision model predicted the bitonic function, and may ultimately provide an integrated account of choice in concurrent chains under both steady-state and dynamic conditions.
Christensen
Darren R
DR
University of Canterbury, Department of Psychology, Private Bag 4800, Christchurch, New Zealand. drc41@student.canterbury.ac.nz
Grace
Randolph C
RC
D000223:Adaptation, Psychological; D000818:Animals; D001245:Association Learning; D002755:Choice Behavior; D010856:Columbidae; D003216:Conditioning, Operant; D003657:Decision Making; D008960:Models, Psychological; D012055:Reinforcement Schedule; D013997:Time Factors