Factors that influence the persistence and relapse of discriminated behavior chains

Abstract

Behavior chains are composed of sequences of behaviors that minimally include procurement and then consumption. This review surveys recent research from this laboratory that has examined the properties of discriminated heterogeneous behavior chains. In contrast to another review (Thrailkill and Bouton, 2016a), it discusses work examining what makes chained behavior persistent, and what makes it relapse. Results suggest that responses in a discriminated heterogeneous behavior chain may become associated, so that extinction of either one reduces the strength of the other. Evidence also suggests that the goal of the first (procurement) response may be the next (consumption) response (rather than the upcoming discriminative stimulus, a putative conditioned reinforcer, or the primary reinforcer at the end of the chain). Further studies suggest that methods that promote generalization across acquisition and extinction (partial reinforcement and delivery of noncontingent reinforcers during extinction) lead to greater persistence of the procurement response. A third set of studies analyzed the contextual control and relapse of chained behaviors. The context controls both the acquisition and extinction of chained behaviors. In addition, a separately-extinguished consumption response is renewed when returned to the context of the chain. The research expands our general understanding of the learning processes that govern instrumental behavior as well as our understanding of chains.

Keywords: Context; Discriminated operant; Extinction; Heterogeneous chains; Persistence; Relapse.

Figure 1

Diagram of events in a discriminated heterogeneous instrumental chain. Procurement (R1; e.g., lever press) and consumption responses (R2; e.g., chain pull) can occur freely. After an intertrial interval (ITI), the procurement SD (S1) turns on. Procurement responses (R1) during S1 can produce the simultaneous offset of S1 and onset of the consumption SD (S2). Consumption responses (R2) during S2 can produce the simultaneous offset of S2, presentation of the reinforcer (food), and initiate the next ITI.

Figure 2

Extinction of R1 following training with partial versus continuous reinforcement. Response rate elevation refers to the response rate (/min) on R1 in the presence of S1 minus R1 response rate during the 30-s period before S1 onset. a.) Response rate elevation in the final session of training (BL; Left) and each block of five S1R1 extinction trials in the test session (Right). b.) response rate elevation scores in 5-trial blocks expressed as proportion of responding in the first block (Block #1) of the test session with common-duration S1 trials. Error bars are the standard error of the mean, Adapted from Thrailkill et al. (2016a).

Figure 3

Extinction of S1R1 following training with noncontingent reinforcers. Response rate elevation refers to the response rate (/min) on R1 in the presence of S1 minus R1 response rate during the 30-s period before S1 onset. a.) Response rate elevation in the final session of training without noncontingent pellets (-1; Left) followed by each session of training with noncontingent pellets prior to each S1R1 (Right). b.) Response rate elevation scores in the test for groups tested with (P) or without (NP) noncontingent pellets expressed a proportion of S1R1 responding in the in final session training with noncontingent pellets (Session 12) 5-trial blocks expressed as a proportion of responding in the first block of the session (Block #1). Error bars are the standard error of the mean, Adapted from Thrailkill et al. (2016a).

Figure 4

Reinstatement of extinguished chained responses. Mean response rate elevation scores for the S1R1 and S2R2 responses that (a.) had received separate extinction of the two responses in separate groups and (b.) extinction of both responses in the chain. In each panel, elevation scores in one set of 5-trial blocks of extinction (Extinction) are followed by those in a second set of 5-trial blocks of extinction (Test). Each set of extinction blocks was separated by a 240 s interval that included 4 noncontingent pellet deliveries separated by 4 s on average (Pellets). Error bars are the standard error of the mean and only appropriate for between-group comparisons

Figure 5

Renewal of extinguished chained responses. Mean responses rate elevation scores for ABA and AAB renewal following (a. and b.) separate extinction of the responses in different groups, and (c. and d.) extinction of the responses in the chain. See text for details. Adapted from Thraikill et al. (2016b).

Figure 6

Contextual control of nonextinguished chained responses. Mean responses rate elevation scores for R1 and R2 over blocks of 5 trials in three extinction sessions. AAB and ABA refer to whether extinction sessions were conducted in the same context as acquisition training (AAB) or took place in a different context (ABA). The top row shows extinction of R1 and R2 in separate group (a. and b.). The bottom row shows extinction of R1 and R2 separately for groups that would eventually receive a test of either R1 or R2 but had each response extinguished as part of the entire (c. and d.) extinction of the responses in the chain. See text for details. Adapted from Thrailkill et al. (2016b).