Mathematical models and the experimental analysis of behavior

The use of mathematical models in the experimental analysis of behavior has increased over the years, and they offer several advantages. Mathematical models require theorists to be precise and unambiguous, often allowing comparisons of competing theories that sound similar when stated in words. Sometimes different mathematical models may make equally accurate predictions for a large body of data. In such cases, it is important to find and investigate situations for which the competing models make different predictions because, unless two models are actually mathematically equivalent, they are based on different assumptions about the psychological processes that underlie an observed behavior. Mathematical models developed in basic behavioral research have been used to predict and control behavior in applied settings, and they have guided research in other areas of psychology. A good mathematical model can provide a common framework for understanding what might otherwise appear to be diverse and unrelated behavioral phenomena. Because psychologists vary in their quantitative skills and in their tolerance for mathematical equations, it is important for those who develop mathematical models of behavior to find ways (such as verbal analogies, pictorial representations, or concrete examples) to communicate the key premises of their models to nonspecialists.     

Rapid acquisition in concurrent chains: evidence for a decision model

Pigeons' choice in concurrent chains can adapt to rapidly changing contingencies. Grace, Bragason, and McLean (2003) found that relative initial-link response rate was sensitive to the immediacy ratio in the current session when one of the terminal-link fixed-interval schedules was changed daily according to a pseudorandom binary sequence (e.g., Schofield & Davison, 1997). The present experiment tested whether the degree of variation in delays across sessions had any effect on acquisition rate in Grace et al.'s (2003) rapid-acquisition procedure. In one condition ("minimal variation"), the left terminal link was always fixed-interval 8 s and the right terminal link was either fixed-interval 4 s or fixed-interval 16 s. In the other condition ("maximal variation"), a unique pair of fixed-interval values was used in each session. Responding was sensitive to the current-session immediacy ratio in both conditions, but across subjects there was no systematic difference in sensitivity. These results challenge the view that initial-link responding in the rapid-acquisition procedure is determined by changes in the learned value of the terminal-link stimuli, and suggests instead that a process resembling categorical discrimination may control performance. A decision model based on the assumption that delays are categorized as short or long relative to the history of delays provided a good account of the data and shows promise in being able to explain other choice phenomena.     

A preliminary analysis of adaptive responding under open and closed economies

In the current investigation, we evaluated the effects of open and closed economies on the adaptive behavior of 2 individuals with developmental disabilities. Across both types of economy, progressive-ratio (PR) schedules were used in which the number of responses required to obtain reinforcement increased as the session progressed. In closed-economy sessions, participants were able to obtain reinforcement only through interaction with the PR schedule requirements (i.e., more work resulted in more reinforcer access). In open-economy sessions, participants obtained reinforcers by responding on the PR schedule and were given supplemental (free) access to the reinforcers after completion of the session. In general, more responding was associated with the closed economy.     

A review of reinforcement control procedures

A demonstration of the effects of reinforcement requires comparison of response rates in the presence of a contingency with those in another condition that controls for the influence of extraneous variables. We describe several control conditions that have been used in evaluating the effects of positive and negative reinforcement. The methodological rigor and practical utility of each type of control condition are discussed, and recommendations for the use of these conditions are presented.     

What does the child analyst bring to Jungian thought?

The author wants to show the influence that the historical acknowledgement of child therapy at the Jerusalem IAAP Congress in 1983 has had today on the Jungian world, especially on the clinical approach to their patients by analysts working only with adult patients. If her conclusions do not allow her to dissociate the strong influence on psychoanalysis of contemporary research on attachment theory and mother-child relationship from a specific Jungian child therapists' perspective, she points out, through three examples from Jungian literature, how the need for a metapsychology of development and the study of primary and personal aspects of the patient's life are explicit in the work and research of analysts working with adults.     

The effects of a seatbelt-gearshift delay prompt on the seatbelt use of motorists who do not regularly wear seatbelts

A seatbelt-gearshift delay was evaluated in two U.S. and three Canadian vehicles using a reversal design. The seatbelt-gearshift delay required unbelted drivers either to buckle their seatbelts or to wait a specified time before they could put the vehicle in gear. After collecting behavioral prebaseline data, a data logger was installed in all five vehicles to collect automated data on seatbelt use. Next the seatbelt-gearshift delay was introduced. The results showed that the delay increased all 5 drivers' seatbelt use, and that the duration of the delay that produced relatively consistent seatbelt use varied across drivers from 5 to 20 s. When the device was deactivated in four of the five vehicles, behavior returned to baseline levels.     

Schedule thinning following communication training: using competing stimuli to enhance tolerance to decrements in reinforcer density

Functional communication training (FCT) is a widely used treatment for individuals with developmental disabilities who exhibit severe behavior problems. One inherent challenge of employing FCT as a treatment in the community is that reinforcement for appropriate communication cannot always be immediate or even possible in some circumstances. Of the few studies that have incorporated some form of schedule thinning for communication, most have reported disruption of communication or increases in problem behavior when the schedule of reinforcement is thinned. In the current study, we compared FCT with extinction to FCT with extinction and access to competing stimuli. After conducting a functional analysis, a competing stimulus assessment was performed to identify stimuli that produce reinforcement that ostensibly competes with reinforcement that maintains problem behavior. It was hypothesized that FCT with competing stimuli would result in more stable reductions in problem behavior during schedule thinning, which would ultimately result in quicker achievement of the treatment goal (low levels of problem behavior under the terminal reinforcement schedule for communication) than FCT without competing stimuli. Results confirmed this hypothesis.     

Acquisition of cocaine self-administration with unsignaled delayed reinforcement in rhesus monkeys

Six experimentally naive rhesus monkeys produced 0.01 mg/kg/infusion cocaine by lever pressing under a tandem fixed-ratio 1 differential-reinforcement-of-other-behavior schedule. One lever press initiated an unsignaled 15- or 30-s delay culminating in cocaine delivery. Each press made during the delay reset the delay interval. With two exceptions, responding was acquired and maintained at higher rates than responding on a second (inoperative) lever. For the exceptions, a cancellation contingency was arranged in which each formerly inoperative-lever response reset the tandem schedule. This manipulation reduced presses on the inoperative lever. Subsequently, the consequences of responding on the two levers were reversed, and the monkeys again responded at higher rates on the operative lever. As a comparison, 3 additional experimentally naive monkeys received response-independent cocaine deliveries. Although lever pressing was observed, it extinguished and was subsequently reestablished under the tandem schedule. The results suggest that although response-reinforcer contiguity is not required for cocaine to acquire reinforcing functions, a response-reinforcer relation appears necessary.     

The effects of noncontingent reinforcement on task disengagement following failure of differential reinforcement treatment

Following the failure of applications of differential reinforcement (DR), the effects of reinforcement delivered noncontingently (NCR) on task disengagement and task completion were evaluated within reversal designs for three children with autism spectrum disorder. In Experiment 1, we compared DR and NCR schedules that combined positive and negative reinforcement. In Experiment 2, we replicated the results of Experiment 1 and then evaluated NCR schedules composed solely of negative reinforcement and NCR schedules that combined negative reinforcement with high-or low-preferred stimuli. In Experiment 3, we further analyzed NCR schedules that included different types and qualities of positive reinforcement, but without the inclusion of negative reinforcement. The results showed that NCR schedules using positive reinforcers can be effective as a treatment for task disengagement, but the type and preference of the reinforcer can alter effectiveness. These results are interpreted in terms of the motivating operations associated with task disengagement.     

Implementing a differential reinforcement of low rates schedule to alter vocal stereotypy and task engagement in two adolescents with autism spectrum disorder

Vocal stereotypy (VS) is often observed in individuals with autism spectrum disorder (ASD) which at high rates can interfere with socialization or functioning in structured settings. There are multiple effective interventions available; yet, many procedures target the complete omission of the behavior or are only assessed at short intervals, making it unclear how they will generalize in applied settings. One intervention yet to be assessed as an individual intervention for automatically reinforced VS is differential reinforcement of low rates of behavior (DRL). In the present study, a functional analysis determined that the VS of two female adolescents with ASD was maintained by automatic reinforcement. A DRL procedure was implemented which incorporated: (a) a specified interval for reinforcement; (b) the behavioral expectations; (c) the permissible instances of VS within the interval; (d) learner feedback; and (e) the reset/non-reset aspect of the schedule. As the targeted behavior decreased across sessions, the DRL interval was systematically increased in order to thin out the schedule of reinforcement. The intervention reduced VS and increased untargeted task engagement for both participants. Applied and theoretical implications of the study as well as social validity, limitations, and future research are discussed.