The Effects of Delayed Reinforcement on Variability and Repetition of Response Sequences

Abstract

Four experiments examined the effects of delays to reinforcement on key peck sequences of pigeons maintained under multiple schedules of contingencies that produced variable or repetitive behavior. In Experiments 1, 2, and 4, in the repeat component only the sequence right-right-left-left earned food, and in the vary component four-response sequences different from the previous 10 earned food. Experiments 1 and 2 examined the effects of nonresetting and resetting delays to reinforcement, respectively. In Experiment 3, in the repeat component sequences had to be the same as one of the previous three, whereas in the vary component sequences had to be different from each of the previous three for food. Experiment 4 compared postreinforcer delays to prereinforcement delays. With immediate reinforcement sequences occurred at a similar rate in the two components, but were less variable in the repeat component. Delays to reinforcement decreased the rate of sequences similarly in both components, but affected variability differently. Variability increased in the repeat component, but was unaffected in the vary component. These effects occurred regardless of the manner in which the delay to reinforcement was programmed or the contingency used to generate repetitive behavior. Furthermore, the effects were unique to prereinforcement delays.

History effects on induced and operant variability

“…The higher susceptibility of repetitive behaviors to disrupting events replicates findings from previous studies with nonhuman animals (e.g., Abreu-Rodrigues, Hanna, Cruz, Matos, & Dela brida, 2004;Neuringer, 1991;Neuringer et al, 2001;Odum, Ward, Barnes, & Burke, 2006;Wagner & Neuringer, 2006;Ward, Bailey, & Odum, 2006). Nevertheless, one might want to view our results with caution.…”

The modulation of operant variation by the probability, magnitude, and delay of reinforcement

“…3) observed that variability in the latency to consume grain reward was greater when there was a 3-s interval between an operant response (i.e., the key peck) and the delivery of grain than when grain was delivered immediately after the response. Other studies have demonstrated that pigeons reinforced for performing a stereotyped sequence of pecks become more variable within the sequence when a delay is inserted between the terminal response and reinforcement (e.g., Odum, Ward, Barnes, & Burke, 2006). …”

Operant variability: A conceptual analysis

“…As Odum, Ward, Barnes, and Burke (2006) pointed out, under a lag n contingency, the U value is a ''relatively molar measure of variability'' (p. 162), because it is calculated from the frequencies at which each sequence was emitted during an entire session. The percentage of reinforced trials, on the other hand, is a measure affected by ''more molecular aspects of variability'' (p. 162).…”