RESPONDING MAINTAINED BY INTERMITTENT REINFORCEMENT: IMPLICATIONS FOR THE USE OF EXTINCTION WITH PROBLEM BEHAVIOR IN CLINICAL SETTINGS

Results of basic research have demonstrated that behavior maintained on an intermittent schedule of reinforcement (INT) will be extinguished more slowly than behavior maintained on a continuous schedule (CRF). Although these findings suggest that problem behaviors may be difficult to treat with extinction if they have been maintained on INT rather than on CRF schedules, few applied studies have examined this phenomenon with human behavior in clinical settings. The purpose of this study was to determine whether problem behavior maintained on CRF schedules would be extinguished more rapidly than behavior maintained on INT schedules. Three individuals diagnosed with profound mental retardation participated after results of pretreatment functional analyses had identified the sources of reinforcement that were maintaining their self-injury, aggression, or disruption. Subjects were exposed to extinction following baseline conditions with CRF or INT schedules alternated within reversal or multielement designs. Results suggested that problem behaviors may not be more difficult to treat with extinction if they have been maintained on INT rather than CRF schedules. However, switching from an INT to a CRF schedule prior to extinction may lower the baseline response rate as well as the total number of responses exhibited during extinction.     

Fixed-interval limited-hold avoidance with and without signalled reinforcement

Rats trained to lever press on a fixed-interval limited-hold avoidance schedule maintained a pattern of responding similar to that maintained by fixed-interval limited-hold schedules of positive reinforcement. But this positively accelerated pattern of behavior was maintained only when the occurrence of reinforcement was signalled by the presentation of a brief flash of light. This result suggests that the discriminative function of the reinforcer in avoidance is less pronounced than the discriminative function of the reinforcer in escape or positive reinforcement. It also suggests that the distinction between positive reinforcement and avoidance is not superfluous. Although the schedule of reinforcement is an important variable in determining the pattern of behavior, other variables, such as the nature (i.e., stimulus presentation, termination, or omission) of the reinforcer, are also potent determinants of behavior.     

Positive conditioned suppression: Transfer of performance between contingent and noncontingent reinforcement situations

Five homing pigeons were trained on concurrent variable-interval schedules. A fixed-duration stimulus was occasionally presented on one key; and, in various conditions, this stimulus terminated (a) without reinforcement, (b) in noncontingent reinforcement, (c) with reinforcement contingent on a response on the key on which the stimulus was presented, and (d) with reinforcement contingent on a response on the key on which the stimulus was not presented. Initially, a stimulus terminating in noncontingent reinforcement generally produced decreased response rates on both keys during the stimulus. Contingencies, however, reliably produced increased rates during the stimulus on the key on which the contingency was arranged, relative to the rate on the concurrently available key. Contingency conditions were followed by noncontingency conditions in which the separation of rates caused by contingencies was maintained. When rates during the stimulus were compared with response rates on the same keys in the absence of the stimulus, contingency-caused rate increases and decreases were again found, but only the rate decreases were maintained in subsequent noncontingency conditions. Further data suggested that the contingency-caused rate changes were not maintained when the stimulus terminated without reinforcement, and that they were unaffected by a threefold decrease in the reinforcement rate provided by the baseline schedules. The results support the suggestion that performance in the positive conditioned suppression procedure results from concurrent and multiple schedule interactions. They further suggest that the production of either acceleration or suppression is dependent on adventitious and historical contingencies.     

THE RELATIVE INFLUENCE OF MOTIVATING OPERATIONS FOR POSITIVE AND NEGATIVE REINFORCEMENT ON PROBLEM BEHAVIOR DURING DEMANDS

Research has demonstrated the feasibility of using positive reinforcement to treat problem behavior maintained by negative reinforcement. This line of research was extended in the current study. A functional analysis (FA) was conducted that suggested problem behavior was maintained by positive and negative reinforcement. Following the FA, a demand analysis was conducted with three demand conditions: one that replicated the demand condition from the FA, one that included presession exposure to a preferred item, and another that included presession exposure to preferred items and access to those items during breaks from demands. Although problem behavior occurred in all three demand conditions, within session analyses showed that problem behavior ceased during breaks from demands only when they included access to preferred items. This finding suggests that the motivating operation responsible for evoking problem behavior did not decrease when only a break was provided. Subsequent functional communication training and treatment analysis showed that treatments based on positive reinforcement were effective at reducing problem behavior, but those based on a negative reinforcement hypothesis were not. Copyright © 2013 John Wiley & Sons, Ltd.     

ARTIFACTUAL EFFECTS OF SENSORY-INTEGRATIVE THERAPY ON SELF-INJURIOUS BEHAVIOR

Three individuals who exhibited self-injurious behavior (SIB) were exposed to sensory-integrative therapy. Prior to treatment, a functional analysis baseline was conducted to identify the motivational features of their SIB. One subject's SIB appeared to be an attention-getting response (maintained by positive reinforcement), which varied subsequently as a function of attention being either withheld or provided noncontingently during sensory-integration sessions. The 2nd subject displayed a pattern of responding suggestive of stereotypic SIB (maintained by automatic reinforcement), which paradoxically increased during sensory-integration sessions. The 3rd subject's SIB appeared to function as an escape response (maintained by negative reinforcement), and his behavior during sensory-integration sessions was similar to that observed during baseline sessions in which demands were not present. The SIB of all 3 subjects later was reduced when behavioral interventions were applied. The data presented raise questions about the active components of sensory-integrative therapy and the functional types of SIB for which it might be appropriate.     

The delay-reduction hypothesis of conditioned reinforcement and punishment: Observing behavior

Pigeons responded in an observing-response procedure in which three fixed-interval components alternated. Pecking one response key produced food reinforcement according to a mixed schedule. Pecking the second (observing) key occasionally replaced the mixed-schedule stimulus with the stimulus correlated with the fixed-interval component then in effect. In Experiment 1, observing was best maintained by stimuli correlated with a reduction in mean time to reinforcement. That finding was consistent with the conditioned-reinforcement hypothesis of observing behavior. However, low rates of observing were also maintained by stimuli not representing delay reduction. Experiment 2 assessed the role of sensory reinforcement. It showed that response rate was higher when maintained by stimuli uncorrelated with reinforcement delay than when the stimuli were correlated with a delay increase. This latter result supports a symmetrical version of the conditioned-reinforcement hypothesis that requires suppression by stimuli correlated with an increase in time to reinforcement. The results were inconsistent with hypotheses stressing the reinforcing potency of uncertainty reduction.     

Animal psychophysics: improvements in the tracking method.

It is difficult to maintain stimulus control in animal psychophysical studies using the tracking method. Loss of stimulus control is characterized by wandering thresholds and responses in the absence of the stimulus. Rats were trained to make a variable number of licking responses to turn on an auditory stimulus. A response on a lever in the presence of the stimulus was reinforced with food. Two precedures were added to improve stimulus control. First, lever responses in the absence of the stimulus raised the intensity of the stimulus at the next presentation; second, rate of reinforcement in the threshold region was maintained at about the same level as that in the suprathreshold region by reducing the number of licking responses required to turn on the stimulus. Using these two procedures, stimulus control was improved and maintained and reliable auditory intensity thresholds were obtained.     

MAINTENANCE OF THERAPEUTIC CHANGE BY MOMENTARY DRO

Differential reinforcement of other behavior (DRO) involves delivery of reinforcement at the end of an interval during which the target behavior has not occurred. Momentary DRO, however, is a procedure in which reinforcement is delivered if a response did not occur at the end of an interval. We examined the extent to which momentary DRO maintained suppression, following initial treatment with whole-interval DRO, of nine retarded students' maladaptive behavior. Results indicate that momentary DRO maintained response suppression comparable to that obtained by whole-interval DRO.     

Yoked variable-ratio and variable-interval responding in pigeons

Pigeons' key pecks were maintained by variable-ratio or variable-interval schedules of food reinforcement. For pairs of pigeons in one group, variable-ratio reinforcement was arranged for one pigeon's pecks; for the second pigeon, reinforcement was arranged according to a variable-interval schedule yoked to the interreinforcement times produced by the first pigeon. For pairs of pigeons in another group, variable-interval reinforcement was arranged for one pigeon's pecks; for the second pigeon, reinforcement was arranged according to a variable-ratio schedule yoked to the interreinforcement responses produced by the first pigeon. For each pair, the yoking procedure was maintained for four or five consecutive sessions of 50 reinforcements each. In more than three-quarters of the pairs, variable-ratio response rates were higher than variable-interval rates within two sessions; in all cases, the rate difference developed within four sessions.     

Schedule control of the vocal behavior of Cebus monkeys

The vocal behavior of three Cebus monkeys was maintained by fixed-ratio schedules of response dependent reinforcement at values between fixed-ratio 1 and fixed-ratio 15. In one monkey that was exposed to variable-interval, fixed-interval, and conjunctive fixed-ratio fixed-interval schedules of reinforcement, vocal responding occurred at a low rate, but schedule-appropriate patterns were maintained. The rates and patterns of responding engendered indicated that the vocal operant can be brought under schedule control in the monkey by the use of response-dependent reinforcement.     

A comparison of differential reinforcement and noncontingent reinforcement for the treatment of a child's multiply controlled problem behavior

Noncontingent reinforcement (NCR) and differential reinforcement of other behavior (DRO) with escape as the reinforcer were evaluated after an initial functional analysis indicated the problem behaviors exhibited by a 7 year old child were maintained by escape. When NCR and DRO did not decrease the problem behaviors, a second functional analysis was conducted and showed that the behaviors were maintained by attention and escape. DRO with attention and escape as reinforcers was compared to NCR with attention and escape as reinforcers for the treatment of the child's multiply controlled behavior problems. Results showed that DRO and NCR were both effective at reducing the problem behavior to low levels and increasing compliance. Copyright © 2003 John Wiley & Sons, Ltd.     

A test of the reinforcing properties of stimuli correlated with nonreinforcement

The information hypothesis of conditioned reinforcement predicts that a stimulus that “reduces uncertainty” about the outcome of a trial will acquire reinforcing properties, even when the stimulus reliably predicts nonreinforcement. Four pigeons' key pecks produced one of two 5-sec stimuli with 0.50 probability according to a discriminated variable-interval schedule. One stimulus was followed by reinforcement; a second stimulus was followed by blackout. To the same extent, therefore, both stimuli reduced uncertainty about the possibility that food would arrive at the termination of the schedule interval. When a second key in the chamber was lighted, each peck on it could produce the stimulus preceding reinforcement, the stimulus preceding nonreinforcement, a novel stimulus, or no stimulus, across separate conditions. The stimulus preceding food maintained responding at substantial levels on the second, stimulus-producing, key. Such responding was not maintained by other stimuli. These data, replicated when the stimuli were reversed on the variable-interval schedule, do not support the prediction that uncertainty-reducing stimuli are necessarily conditioned reinforcers.     

Some experiments on the organization of a class of imitative behaviors

A retarded child was taught to imitate diverse demonstrations made by an experimenter, until new demonstrations were imitated correctly upon first presentation without direct training. These imitations could be maintained without reinforcement, when they were distributed among other reinforced imitations. Factors responsible for the continued performance of these unreinforced imitations were examined. When subjected to massed extinction trials, unreinforced imitations eventually disappeared; they reappeared when again interspersed among reinforced imitations. In addition, the stimulus function of "similarity of response between subject and experimenter" was examined. The subject was taught a set of non-imitative responses, through discriminative stimuli controlled by the experimenter, and a comparable imitative set. Unreinforced non-imitations, like reinforced imitations, were maintained only when interspersed among reinforced imitations. When all reinforcement was discontinued, all responses extinguished similarly, indicating that reinforcement was necessary to maintain the response-class organization, but not confirming an essential role for "similarity" as such.     

Concurrent performances: inhibition of one response by reinforcement of another

In an analysis of interactions between concurrent performances, variable-interval reinforcement was scheduled, in various sequences, for both keys, for only one key, or for neither key of a two-key pigeon chamber. With changeover delays of 0.5 or 1.0 sec, and with each key's reinforcements discriminated on the basis of key-correlated feeder stimuli, reinforcement of pecks on one key reduced the pecking maintained by reinforcement on the other key. The decrease in pecking early after reinforcement was discontinued on one key was not substantially affected by whether pecks on the other key were reinforced, but after reinforcement was discontinued on both keys, reinstatement of reinforcement for one key sometimes produced transient increases in pecking on the other key. Correlating the availability of right-key reinforcements with a stimulus, which maintained right-key reinforcement while reducing right-key pecking to negligible levels, demonstrated that these interactions depended on concurrent reinforcement, not concurrent responding. Thus, reinforcement of a response, but not necessarily the occurrence of the response, inhibits other reinforced responses. Compared with accounts in terms of excitatory effects of extinction, often invoked in treatments of behavioral contrast, this inhibitory account has the advantage of dealing only with observed dimensions of behavior.     

The role of the response-reinforcer contingency in negative automaintenance

When a response key is briefly illuminated before a grain reinforcer is presented, key pecking is reliably developed and maintained in pigeons, even if pecking prevents reinforcement (negative automaintenance). This experiment demonstrated that pigeons are sensitive to a negative response-reinforcer contingency, even though it does not eliminate responding. Within individual pigeons, two kinds of trials were compared: red key trials, in which reinforcement was negatively contingent on responding, and white key trials, in which reinforcement was unrelated to responding. Reinforcement frequency in non-contingent trials was yoked to the obtained reinforcement frequency in negatively contingent trials. All eight pigeons pecked substantially more on the non-contingent key than on the negative key, and preferred the non-contingent key to the negative key on occasional “choice” trials where both were presented together. When the stimuli correlated with the two conditions were reversed, the pigeons' behavior also shifted. These response differences are taken as evidence that pigeons are sensitive to the negative response-reinforcer contingency.     

Concurrent ratio schedules: Fixed vs. variable response requirements

Rats were trained on concurrent fixed-ratio variable-ratio or concurrent fixed-ratio mixed-ratio schedules of food reinforcement. The variable-ratio schedule was composed of an arithmetic sequence of 11 ratios that averaged 50; the mixed-ratio schedule consisted of equiprobable ratios of 1 and 99. Fixed-ratio values, varied over experimental conditions, included 25, 35, 50, 60, and 99. The proportion of responses and time allocated to the variable- or mixed-ratio schedule increased as the size of the fixed ratio increased. For most subjects, higher proportions of responses and time were maintained on the fixed-ratio schedule at fixed-ratio values of 25 and 35; higher proportions of responses and time were maintained on the variable- or mixed-ratio schedule at fixed-ratio values of 50 or higher. On concurrent variable-ratio fixed-ratio schedules, the tendency for responding to be maintained exclusively by one schedule was related to the difference in local reinforcement rates obtained from those schedules. Exclusive responding was approximated when the difference in local reinforcement rates obtained from those schedules was large; responding was more evenly distributed between the schedules as the difference in the rates at which reinforcement was obtained from each decreased.     

EFFECTS AND SIDE EFFECTS OF DRO AS TREATMENT FOR SELF-INJURIOUS BEHAVIOR

A three-part controlled case study is presented in which severe and longstanding self-injurious behavior exhibited by a 9-year-old-boy was treated successfully with differential reinforcement of other behavior. In Phase 1, an experimental analysis demonstrated that the boy's scratching was not maintained by environmental contingencies; instead, it appeared that the self-injurious behavior was a stereotypic (automatically reinforced) response. In Phase 2, the effects of an escalating differential-reinforcement-of-other-behavior schedule mediated through token reinforcement (pennies) were evaluated in a reversal design. Results showed that differential-reinforcement-of-other-behavior eliminated self-injurious behavior very quickly and for periods of time as long as 30 min. A noteworthy side effect observed during Phase 2 was the occurrence of crying behavior following the nondelivery of reinforcement. In Phase 3, the token program was gradually extended in 30-min increments throughout the day. Additionally, results of a brief multielement manipulation showed that the effects of token reinforcement were superior to those of a more easily administered differential reinforcement of other behavior based on social reinforcement, which differed little from baseline.     

A quantitative analysis of the responding maintained by interval schedules of reinforcement

Interval schedules of reinforcement maintained pigeons' key-pecking in six experiments. Each schedule was specified in terms of mean interval, which determined the maximum rate of reinforcement possible, and distribution of intervals, which ranged from many-valued (variable-interval) to single-valued (fixed-interval). In Exp. 1, the relative durations of a sequence of intervals from an arithmetic progression were held constant while the mean interval was varied. Rate of responding was a monotonically increasing, negatively accelerated function of rate of reinforcement over a range from 8.4 to 300 reinforcements per hour. The rate of responding also increased as time passed within the individual intervals of a given schedule. In Exp. 2 and 3, several variable-interval schedules made up of different sequences of intervals were examined. In each schedule, the rate of responding at a particular time within an interval was shown to depend at least in part on the local rate of reinforcement at that time, derived from a measure of the probability of reinforcement at that time and the proximity of potential reinforcements at other times. The functional relationship between rate of responding and rate of reinforcement at different times within the intervals of a single schedule was similar to that obtained across different schedules in Exp. 1. Experiments 4, 5, and 6 examined fixed-interval and two-valued (mixed fixed-interval fixed-interval) schedules, and demonstrated that reinforcement at one time in an interval had substantial effects on responding maintained at other times. It was concluded that the rate of responding maintained by a given interval schedule depends not on the overall rate of reinforcement provided but rather on the summation of different local effects of reinforcement at different times within intervals.     

Comparison of blocking strategies informed by precursor assessment to decrease pica

Pica is dangerous behavior and often maintained by automatic reinforcement. We conducted a latency functional analysis (FA) using safe consumption items to verify that pica was maintained in part by automatic reinforcement and exclude participants for whom pica was likely maintained solely by attention. Next, we identified precursors to pica through a probability analysis and conducted a brief blocking assessment for participants' whose pica occurred in the alone and attention conditions of the FA. Finally, we compared blocking precursors with pica, touching an inedible item and the pica itself. Results showed that five of the six participants' pica was likely maintained by automatic reinforcement, and pica decreased during the brief blocking assessment for three of four participants. Results of the blocking comparison showed that blocking behaviors earlier in the response hierarchy was as effective as only blocking pica attempts for two participants and more effective for one participant.     

Case study: Improving the social interactions of a group home resident with severe and multiple disabilities

A 43-year-old man with severe mental retardation and sensory impairments and a long history of behavior problems was taught to interact more appropriately with staff members at his community-based group home. The following behaviors were targeted for change within a multiple baseline design: use of an appropriate cueing response to initiate a conversation; keeping his hands to himself when conversing with another; and not ‘badgering’ people by repeating the same question over and over. Instructions and feedback produced small, unstable improvements in the subject's behavior. When token reinforcement was added to the treatment package, large and immediate improvements were noted. The improved levels of social interactions were maintained after token reinforcement was withdrawn, suggesting the operation of naturally occurring contingencies of reinforcement.