SOME EFFECTS OF PROCEDURAL VARIATIONS ON CHOICE RESPONDING IN CONCURRENT CHAINS

The present research used pigeons in a three‐key operant chamber and varied procedural features pertaining to both initial and terminal links of concurrent chains. The initial links randomly alternated on the side keys during a session, while the terminal links always appeared on the center key. Both equal and unequal initial‐link schedules were employed, with either differential or nondifferential terminal‐link stimuli across conditions. The research was designed to neutralize initial‐ and terminal‐link spatial cues in order to gain a clearer understanding of the roles of conditioned reinforcement and delayed primary reinforcement in choice. With both equal and unequal initial links and with differential terminal‐link stimuli, all pigeons reliably preferred the chain with the shorter terminal link. However, with equal initial links and nondifferential stimuli, all pigeons were indifferent. With unequal initial links and nondifferential stimuli, some pigeons were also indifferent, while others actually reversed and preferred the chain with the shorter initial link, even though it was followed by the longer terminal link. The decrease if not reversal of the previous preferences implies that preferences in concurrent chains are a function of the conditioned reinforcement afforded by terminal‐link stimuli, rather than delayed primary reinforcement.     

Negative reinforcer magnitude manipulations for treating escape-maintained problem behavior

The purpose of the current study was to evaluate the effects of different magnitudes of escape for compliance relative to the magnitudes of escape for problem behavior in a concurrent-schedule arrangement. Three individuals who exhibited escape-maintained problem behavior participated. A large differential magnitude condition (240-s escape for compliance, 10-s escape for problem behavior) was compared to equal (30-s escape for compliance and problem behavior) and moderate differential magnitude (90-s escape for compliance, 10-s escape for problem behavior) conditions. The authors also evaluated the impact of correcting for reinforcer access time (i.e., time on escape intervals) on intervention interpretation. For all participants, problem behavior decreased during only the large differential magnitude condition, and including reinforcer access time in the overall session time did not affect interpretation of treatment outcomes. Providing larger escape magnitudes for compliance relative to problem behavior may facilitate treatment involving concurrent-reinforcement schedules for escape-maintained problem behavior.     

Comparing the effects of varied and constant preferred items on improving tummy time for typically developing infants

Tummy time involves placing an infant in a prone position to help build muscle strength. Pediatricians recommend tummy time because it helps with infant development related to milestones such as crawling, rolling over, and sitting up. However, parents sometimes avoid tummy time due to whining or crying when the infant is placed in the prone position. The current study compared two interventions incorporating preferred leisure items (i.e., varied or constant) for five typically developing infants to increase head elevation and decrease negative vocalizations during tummy time. Improvements occurred in infant performance regardless of the preferred items used. In addition, the mothers who implemented the tummy time procedures found the treatment to be socially valid and were more likely to select the use of the constant item when given the opportunity to choose.     

Differential reinforcement-of-low-rate procedures: A systematic replication with students with autism spectrum disorder

Becraft, Borrero, Davis, Mendres-Smith, and Castillo (2018) studied the effects of two different types of DRL schedules (full session and spaced responding) under 2 sets of stimulus conditions (with and without signals). Reduced rates of responding maintained under both types of DRL schedules, when signals were included. The present study represents a replication of procedures by Becraft et al. involving learners with autism spectrum disorder (ASD). The results replicated those of Becraft et al. in that responding in both full-session and spaced-responding DRL schedules was low, but not eliminated. These results provide preliminary evidence to suggest that children with ASD are responsive to signals in DRL arrangements, which may set the stage for evaluation of signaled DRL arrangements for socially significant response forms.     

Differential negative reinforcement of other behavior to increase compliance with wearing an anti-strip suit

Using a changing-criterion design, we replicated and extended a study (Cook, Rapp, & Schulze, 2015) on differential negative reinforcement of other behavior (DNRO). More specifically, educational assistants implemented DNRO to teach a 12-year-old boy with autism spectrum disorder to comply with wearing an anti-strip suit to prevent inappropriate fecal behavior in a school setting. The duration for which the participant wore the suit systematically increased from 2 s at the start of treatment to the entire duration of the school day at the termination of the study. Moreover, these effects were generalized to a new school with novel staff and persisted for more than a year. These findings replicate prior research on DNRO and further support the use of the intervention to increase compliance with wearing protective items, or medical devices, in practical settings.     

Further analysis of modifications to the three-step guided compliance procedure to enhance compliance among children with autism

Three-step guided compliance (vocal prompt, vocal plus model prompt, vocal prompt plus physical guidance) is a commonly used procedure to increase compliance among children with intellectual disabilities. Previous research has suggested that under some conditions, slight modifications to the three-step procedure may enhance its effectiveness. These modifications include omitting the model prompt and decreasing the interprompt interval. In the current study, we evaluated another modification to the procedure: the delivery of a high-preference item contingent upon compliance with the first vocal prompt (i.e., differential reinforcement). For 2 participants with autism, compliance remained low when we implemented differential reinforcement and the guided compliance procedure in isolation. However, compliance improved when we combined differential reinforcement and the three-step guided procedure, suggesting that for at least some children, the combination of contingent access to a high-preference item and the guided compliance procedure is more effective than either intervention alone.     

Comparing the reinforcing efficacy of tokens and primary reinforcers

Token economies are one of the most commonly used behavior-analytic interventions. Despite literature supporting the use of tokens as tools for behavior change, little is known about the efficacy of tokens compared to that of the items for which they are exchanged. Results of previous research comparing the reinforcing efficacy of tokens and primary reinforcers have shown that both produce similar effects on responding. However, published findings have been confounded given the inclusion of primary reinforcers in the token-reinforcer test conditions. In this study, we established novel tokens as reinforcers. We then conducted a conditioned-reinforcer assessment using a tandem control to ensure that the tokens functioned as reinforcers. We used progressive-ratio schedules to compare the reinforcing efficacy of the tokens to high- and low-preference edibles that were also used as backup reinforcers. For both participants, we found that high-preference primary reinforcers maintained higher response frequencies than did tokens.     

An evaluation of synchronous reinforcement for increasing on-task behavior in preschool children

A synchronous-reinforcement schedule is a type of schedule of covariation in which the onset and offset of the reinforcer covaries with the onset and offset of behavior. This study was a proof-of-concept demonstration of the efficacy of synchronous reinforcement for on-task behavior (completing a preacademic skill) and an evaluation of preschoolers' preference for this schedule in comparison to a more traditional schedule of reinforcement. Specifically, we compared the effects of a synchronous-reinforcement schedule to one in which continuous access to stimuli was delivered at the end of the session and yoked to the duration of on-task behavior that occurred during the session (accumulated reinforcement). Results showed the synchronous-reinforcement schedule was more effective for increasing on-task behavior and preferred by most participants.     

Effects of time-based administration of abstinence reinforcement targeting opiate and cocaine use

Polydrug use is a common problem among patients in opioid-substitution treatment. Polydrug use has been reduced by administering abstinence-reinforcement contingencies in a sequence, such that a single drug is targeted until abstinence is achieved, and then an additional drug is targeted. The present study examined effects of administering abstinence-reinforcement contingencies sequentially based on time rather than on achieved abstinence. Participants accessed paid work (about $10/hr maximum) in the Therapeutic Workplace by providing urine samples 3 times per week. The urine samples were tested for opiates and cocaine. During an induction period, participants earned maximum pay independent of drug abstinence. Then, maximum pay depended upon urine samples that were negative for opiates. Two weeks later, maximum pay depended upon urine samples that were negative for both opiates and cocaine. Opiate and cocaine abstinence increased following administration of the respective contingencies. The time-based administration of abstinence reinforcement increased opiate and cocaine abstinence.     

Testing the Δ-∑ hypothesis in the suboptimal choice task: Same delta with different probabilities of reinforcement

In a concurrent-chain procedure, pigeons choose between 2 initial-link stimuli; one is followed by terminal link stimuli that signal reliably whether food will be delivered after a delay; the other is followed by terminal link stimuli that do not signal whether food will be delivered after the delay. Pigeons prefer the former alternative even when it yields a lower overall probability of food. Recently, we proposed the Delta-Sigma (∆-∑) hypothesis to explain the effect: Preference depends on the difference (∆) between the reinforcement probabilities associated with the terminal link stimuli, and the overall probability of reinforcement (∑) associated with the alternative. The hypothesis predicts that, for constant ∑, animals should prefer alternatives with greater ∆ values regardless of the specific probabilities of reinforcement that determine ∆. In 2 experiments, we tested this prediction by comparing a ∆ = .5 against a ∆ = 0 alternative, with the former obtained with different pairs of reinforcement probabilities across conditions. The results supported the hypothesis when the 2 probabilities defining ∆ were significantly greater than 0, but not when one of them was close to 0. The results challenge our theoretical accounts of suboptimal choice and the variables considered to determine pigeons’ preference.