Elsevier

Behavioural Processes

Volume 181, December 2020, 104257
Behavioural Processes

Does DRO type matter?: Cycle versus resetting contingencies in eliminating responding

https://doi.org/10.1016/j.beproc.2020.104257Get rights and content

Abstract

Following lever-press training on variable-interval 30-s schedules, rats were exposed to three types of schedules designed to eliminate lever pressing. The first two were variations on what is called a differential-reinforcement-of-other-behavior (DRO, “zero rate”, or [target response] omission schedule) schedule. Under both variations, reinforcers were scheduled to occur in different conditions after either fixed or variable inter-reinforcer intervals (IRIs). Under one variation each lever press reset the time interval (i.e., “resetting DRO”) and under the other a reinforcer delivery scheduled at the end of an IRI was cancelled by the first response during the IRI (i.e., “cycle DRO”). In another condition reinforcers were delivered independently of responding after fixed or variable time periods. Each of the DRO procedures reduced response rates quickly and to near zero across ten sessions. The time schedules also reduced responding, albeit at a slower rate. The results extend the analogy of omission training to freeoperant avoidance to shock-deletion avoidance schedules.

Introduction

Reinforcement of the absence of a target response has remained a focus of discussion and analysis since first described by Skinner (1938 p. 141). Reynolds (1961) gave the procedure its most common label, differential reinforcement of other behavior or DRO. Kelleher (1961) described it as the differential reinforcement of pausing, and others (e.g., Uhl and Garcia, 1969) have labeled the “O” of DRO as “zero rates” or “omission [of the target response].” In the earliest analyses of the DRO schedule, each response simply reset a fixed period of time (the inter-reinforcer interval, or IRI) that had to elapse before reinforcer delivery, a procedure labeled a resetting DRO. This schedule arrangement is what is meant by the most common usage of the term DRO. Uhl and Garcia (1969) first noted the procedural similarities between DRO and free-operant avoidance (FOA; Sidman, 1953, 1966). In both procedures, each response postpones the scheduled event (aversive stimulus or reinforcer delivery, respectively), with FOA maintaining responding and DRO reducing or eliminating it. Uhl and Garcia found that the speed with which DRO eliminated responding was a function of both the duration of the interval between successive responses, analogous to the response-shock interval in FOA, and the time between successive reinforcer deliveries in the absence of responding, analogous to the FOA shock-shock interval.

Uhl and Garcia’s analogy suggests others between avoidance schedules and DRO. Sidman (1966), for example, described a fixed-cycle avoidance procedure in which the first response during a fixed period cancelled a shock that otherwise occurred at the end of the period. Shabani, Wilder, and Flood (2001; see also Gehrman et al., 2017) investigated an analogous DRO procedure, labeled a nonresetting DRO (see also Jessel and Ingvarsson, 2018), in which a target response during any of the equal-duration fixed periods into which the session was divided cancelled the reinforcer delivery scheduled at the end of the period. When that period lapsed, the next one started. An important difference between Sidman’s fixed-cycle avoidance contingency and Gehrman et al.’s nonresetting DRO is that in the former there were no exteroceptive stimuli associated with the fixed period, but in the latter, “[t]he experimenter showed [the participant] the reset interval on [a programmable timer], but said nothing” (Gehrman et al., p. 244; D. Wilder, personal communication, August 17, 2020).

Consistent temporal stimuli from the target response to the event, shock or positive reinforcer delivery, in both Sidman’s (1966) and Gehrman et al.’s procedures were somewhat obscured because the time from the last response to either the shock or the reinforcer was variable. In Gehrman et al. (2017), however, the presence of the timer could have served as a discriminative stimulus for target-response omission. Whereas the variable time periods were determined by the subject’s performance (specifically, where in the fixed interval the response occurred) in both Sidman’s and Gehrman et al.’s procedures, deVilliers (1972, 1974) scheduled shock delivery to occur at the end of explicitly programmed variable-time periods in the absence of the target response during each such period. The first response in each period cancelled the scheduled shock delivery. No exteroceptive discriminative stimuli were present. Yet another arrangement, a variable-momentary (VM) DRO schedule, also delivers a reinforcer at the end of a variable-duration IRI. Unlike deVilliers’s variable-cycle shock-avoidance procedure, however, under the VMDRO a reinforcer occurs if the target response is omitted only during a specified period toward the end of the IRI (e.g., the last 5 s; Lindberg et al., 1999).

The first purpose of the present experiment was to extend the analogy between avoidance and DRO schedules to that between a variable-cycle avoidance schedule and an analogous DRO arrangement. The second purpose was to compare both fixed- and variable-cycle DRO schedules (i.e., nonresetting DROs) to resetting DRO schedules in which each response during either a fixed or variable interreinforcer interval reset the interval. Gehrman et al. (2017) found resetting and nonresetting (i.e., fixed-cycle) DROs to be equally effective in eliminating responding. As noted previously, however, both of their delays were associated with exteroceptive stimuli (the timer), which may have contributed to their effectiveness. Such comparisons have not been made for variable-cycle resetting and nonresetting DROs. The third purpose was to compare response reduction by the different DRO schedules to that induced by another response-reduction procedure: eliminating the response-reinforcer dependency, thereby creating a fixed- or variable-time schedule (FT and VT, respectively; Zeiler, 1968).

Nineteen male albino Sprague–Dawley rats aged approximately 7 months at the start of the experiment were used. Each had exposure to VI reinforcement schedules and extinction (EXT) several months prior to the present experiment. Rats were pair housed in a vivarium with a 12:12-hr light/dark cycle and with continuous access to water. Post-session feedings occurred 30 min after sessions ended, resulting in approximately 22 h of food restriction at session onset.

Ten Med-Associates modular test chambers, Model ENV-008-VP, with work areas 30 cm long x23.5 cm wide x21 cm high were used. A pellet magazine dispensed 45-mg food pellets to a 5-cm square recessed aperture on the same wall of the chamber where two 2.5-cm wide levers (one inactive) were located 3-cm away from the aperture. A houselight, centered 18.5 cm from the chamber floor on the opposite wall, illuminated the chamber. A desktop computer controlled the experiment and recorded the data using Microsoft Visual Basic Express 2010® software.

No magazine training or shaping was required because rats had previous experimental histories. Daily sessions occurred during the dark phase of the light-dark cycle at about the same time each day. Each session terminated after 60 reinforcer deliveries. Twelve variable interreinforcer intervals (IRIs) were derived from Fleshler and Hoffman (1962) progression and selected randomly without replacement. All rats first were exposed to a 14-session baseline condition during which lever pressing was reinforced according to a VI 30-s schedule. The following conditions then were investigated:

Reinforcers occurred every 30 s in the absence of lever pressing. Each lever press reset the IRI such that 30 s had to elapse without a response for the next reinforcer delivery.

Reinforcers were scheduled to occur every 30 s. The first lever press in the current 30-s IRI cancelled the reinforcer delivery scheduled at its end. Additional responses in the IRI had no effect. After the 30-s IRI elapsed, a new 30-s IRI was initiated whether a reinforcer was delivered or not. This schedule was analogous to fixed-cycle free-operant avoidance (Baron, 1991).

Reinforcers occurred on average every 30 s in the absence of lever pressing. Each lever press reset the current IRI. Following reinforcer delivery, the next IRI was selected without replacement from the array and initiated.

Reinforcers were scheduled on average every 30 s. The first lever press in the current IRI cancelled the reinforcer delivery scheduled at its end. Additional responses in the current IRI had no effect. After the current IRI elapsed, a new IRI was selected without replacement from the array and initiated whether a reinforcer was delivered or not. This schedule was analogous to variable-cycle free-operant avoidance (Baron, 1991; deVillers, 1974).

Nine rats (one rat was discontinued for health reasons and its incomplete data were excluded from the analysis) were exposed to the fixed schedules (Sections 2.3.1 and 2.3.2) and ten rats to the variable schedules (Sections 2.3.3 and 2.3.4). There were four sequences of conditions (labeled Sq1-Sq4 in Fig. 1, Fig. 2). Of the rats receiving the fixed schedules, four rats were first exposed to the FDRO schedules and five were first exposed to the FCDRO schedule. Of those rats exposed to the variable schedules, five first exposed to the VDRO schedule and five were first exposed to the VCDRO schedule. A return to the baseline VI schedule separated exposure to each of the DRO schedules. After a final return to the baseline VI schedule, all of the rats in the fixed and variable groups were exposed to a fixed- or variable-time (FT or VT) schedule, respectively, for a final 10 sessions in which reinforcers were delivered independent of responding. In each of the time schedules, reinforcer rates and distributions were yoked, on a session-by-session basis, to the individual reinforcer distribution and frequency that occurred during each of successive sessions of the 10-session long second DRO condition (e.g., Session 1 of the FT schedule for that sequence was yoked to Session 1 of the FCDRO schedule, etc.).

Response and reinforcement rates of each rat were calculated by dividing the number of active lever responses and reinforcers by the total session time. Response rates then were used to normalize individual response rates under the DRO and time schedules by dividing the response rate in a given DRO session by the average of the last six sessions of the immediately preceding individual baseline response rate. A two-way repeated-measures ANOVA with a Geisser-Greenhouse correction with both schedule and session as within-subject factors was conducted with a Tukey’s multiple comparisons test comparing these normalized response rates and reinforcement rates Normalized response rates were used in these comparisons because baseline VI schedules of reinforcement allow for wide variability in response rates, while maintaining approximately equal reinforcement rates (Kuroda et al., 2018). Comparisons were made only among those rats that were exposed to either fixed or variable schedules (i.e., no direct comparisons were made between fixed and variable schedules, because these comparisons could only be made across individual subjects and not within subjects). All statistical tests were conducted using GraphPad Prism Version 8.3.1 for Windows (GraphPad Software, La Jolla, California) with α = .05. For all significant differences detected, effect sizes were calculated and reports as generalized eta-squared (ηG; Bakeman, 2005; Olejnik and Algina, 2003) to accommodate individual subject variation in all effect-size statistics.

Section snippets

Results

Mean (and standard deviation) baseline response and reinforcement rates are shown in Table 1. Fig. 1, Fig. 2 show, respectively, the absolute and proportional response rates during the different DRO and time schedules. Each data point is the average for the rats exposed to the conditions as described in the Procedure section. The four top graphs in Fig. 1 show response rates during the VI baseline (BSL) and the DRO and time schedules indicated above each condition, in the sequence in which they

Discussion

Following response maintenance on VI schedules, resetting and cyclic (nonresetting) DROs reduced responding at equivalent rates and to near-zero levels. The comparisons suggest that, within the constraints described below, the two types of DROs are functionally equivalent. The results further suggest that the analogue of DRO arrangements to schedules of negative reinforcement suggested by Uhl and Garcia (1969) extend to the cyclic avoidance procedures described by Sidman (1966) and deVilliers

Authors’ note

The authors thank Dave Wilder for sharing his insights about nonresetting DROs.

CRediT authorship contribution statement

Tyler D. Nighbor: Conceptualization, Formal analysis, Methodology, Writing - original draft. Jemma E. Cook: Conceptualization, Formal analysis, Methodology, Writing - original draft, Writing - review & editing. Anthony C. Oliver: Writing - review & editing. Kennon A. Lattal: Conceptualization, Methodology, Supervision, Writing - review & editing.

Declaration of Competing Interest

None.

References (24)

  • D. Anger et al.

    Behavior changes during repeated eight-day extinctions

    J. Exp. Anal. Behav.

    (1976)
  • R. Bakeman

    Recommended effect size statistics for repeated measures designs

    Behav. Res. Methods

    (2005)
  • A. Baron

    Avoidance and punishment

  • J.E. Cook et al.

    Changes in the elimination and resurgence of alcohol-maintained behavior in rats and the effects of naltrexone

    Psychol. Addict. Behav.

    (2019)
  • J. Davis et al.

    Differential reinforcement of other behavior (DRO): a yoked control comparison

    J. Exp. Anal. Behav.

    (1971)
  • P.A. deVilliers

    Reinforcement and response rate interaction in mulcitple random-interval avoidance schedules

    J. Exp. Anal. Behav.

    (1972)
  • P.A. deVilliers

    The law of effect and avoidance: a quantitative relationship between response rate and shock-frequency reduction

    J. Exp. Anal. Behav.

    (1974)
  • M. Fleshler et al.

    A progression for generating variable-interval schedules

    J. Exp. Anal. Behav.

    (1962)
  • C. Gehrman et al.

    Comparing resetting to non-resetting DRO procedures to reduce stereotypy in a child with autism

    Behav. Interv.

    (2017)
  • J. Jessel et al.

    Recent advances in applied research on DRO procedures

    J. Appl. Behav. Anal.

    (2018)
  • B. Katz et al.

    An experimental analysis of the extinction‐induced response burst

    J. Exp. Anal. Behav.

    (2020)
  • R.T. Kelleher

    Schedules of conditioned reinforcement during experimental extinction

    J. Exp. Anal. Behav.

    (1961)
  • Cited by (1)

    View full text