Relative preference for distinct reinforcers maintaining destructive behavior

The literature offers few recommendations for sequencing exposure to treatment conditions with individuals with multiply maintained destructive behavior. Identifying relative preference for the functional reinforcers maintaining destructive behavior may be one means of guiding that decision. The present study presents a preliminary attempt at developing a robust relative preference and reinforcer assessment for individuals with multiply maintained destructive behavior. Guided and free-choice trials were implemented in which participants chose between two multiple-schedule arrangements, each of which programmed signaled periods of isolated reinforcer availability and unavailability. Consistent participant choice and responding during free-choice trials was then used to thin the corresponding schedule of reinforcement. The results demonstrated a strong preference for one of the two functional reinforcers for all four participants, yet preferences differed across participants and were not well predicted by responding in prior analyses.     

Evaluation of a treatment package to reduce rapid eating

We replicated and extended treatment procedures described by Lennox, Miltenberger, and Donnelly (1987) designed to reduce rapid eating. The participant was a 17-year-old girl with developmental disabilities who engaged in dangerously high rates of food ingestion. The procedure involved an adjusting differential-reinforcement-of-low-rate-responding (DRL) schedule, response blocking, and prompts. We evaluated a continuation of the treatment despite initial negative side effects that were similar to those reported by Lennox et al. Results showed that the treatment package was effective and negative side effects eventually decreased.     

The effects of magnitude and quality of reinforcement on choice responding during play activities

Three boys with autism participated in a study of the effects of magnitude and quality of reinforcement on choice responding. Two concurrent response alternatives were arranged: (a) to play in an area where a peer or sibling was located, or (b) to play in an area where there was no peer or sibling. During one condition, the magnitude (i.e., duration of access to toys) or quality (level of preference) of reinforcement provided for both responses was equal. During the other condition, the magnitude or quality of reinforcement was relatively greater for choosing the play area where the peer or sibling was located than the area where the peer or sibling was not located. Results showed that after repeated exposure to the unequal magnitude or quality condition, the participant increasingly allocated his responses to the play area where the peer or sibling was located. For 2 participants, this pattern of responding was maintained in the subsequent equal magnitude or quality condition. Overall, the analysis suggests that the dimensions of magnitude and quality of reinforcement can be arranged to influence choice responding in favor of playing near a peer or sibling rather than playing alone.     

GENERALIZED IMITATION AND RESPONSE-CLASS FORMATION IN CHILDREN WITH AUTISM

An experimental analysis of imitation was conducted to examine the influence of response topography on generalization of imitation across three response types. Four children with autism were presented with both reinforced training trials and nonreinforced probe trials of models from vocal, toy-play, and pantomime response types. The probe trials were used to examine generalization within each response type. A multiple baseline design was used to analyze percentage of matching and nonmatching responses to models across response types. This study, the first to analyze imitative response classes in children with autism, showed that imitation generalized from reinforced training models to nonreinforced probe models within a response type, but it did not generalize across response types. Thus, functional response classes determined by topographical boundaries were exhibited within generalized imitation.     

The effects of smoked marijuana on progressive-interval schedule performance in humans.

In three experiments, 8 human subjects participated in a study of the effects of smoked marijuana on progressive-interval schedule performance. A two-component chained progressive-interval fixed-interval schedule of point delivery was used. In the progressive-interval component, the interval length began at 20 s and increased either geometrically or arithmetically (by either 20 s, 40 s, 80 s, 100 s, or 160 s) on each subsequent interval. After this interval elapsed, a single button press produced the fixed-interval component, with a total of five reinforcers of varying magnitude ($0.05, $0.20, or $0.40) available on a fixed-interval 20-s schedule. After the five reinforcer deliveries, the schedule returned to the initial progressive-interval component. Several relationships were found among rates of responding, postreinforcement pauses and drug administration in the progressive-interval component: (a) Postreinforcement pauses increased as the temporal requirements of the progressive-interval schedule increased; (b) rates of responding during successive progressive-interval components rapidly decreased to low rates of responding after the first few progressions; (c) postreinforcement pauses decreased systematically as dose of smoked marijuana increased; and (d) rates of responding increased after smoking active marijuana but not after smoking placebo cigarettes. Results are discussed in the context of behavioral control and relevance to other studies that have investigated the effects of smoked marijuana on schedule performance.     

Within-session Analysis Of Visual Discrimination

Within-session changes in responding by pigeons during a maintained successive discrimination procedure were examined in four experiments. In the first two experiments, which involved discrimination of visual flicker rate, within-session changes in responding were minimal or absent. A third experiment, which examined discrimination of rectangular forms, demonstrated that the absence of within-session changes in responding was not limited to flicker-rate stimuli. A fourth experiment showed that the absence of within-session changes in responding was not due to high task difficulty in the previous experiments. For the group of subjects in each experiment, within-session changes in responding did not influence discrimination performance. Therefore, measures of overall response rate accurately represented responding both within and across sessions. The occasional appearance of within-session decreases in responding for a few birds may be attributable to satiation.     

EFFECTS OF SPACED RESPONDING DRL ON THE STEREOTYPED BEHAVIOR OF PROFOUNDLY RETARDED PERSONS

Stereotypic responding and social behaviors of three profoundly retarded children were measured before and during application of a DRL contingency for stereotypic responding. A variant of the standard DRL procedure, spaced responding DRL, was used, in which reinforcement is delivered following a response if that response has been separated from the previous response by at least a fixed minimum time interval. Three children were treated by using a reversal design. Results showed that: (a) during baseline sessions, the children engaged in high rates of stereotypic responding and very low rates of appropriate social behavior; and (b) during DRL sessions, appropriate behavior increased markedly as stereotypic responding was reduced. The data suggest that spaced responding DRL may be effective in increasing appropriate social behavior as well as in reducing stereotypic responding.     

Temporal control by progressive-interval schedules of reinforcement.

Progressive-interval performances are described using measures that have proven to be successful in the analysis of fixed-interval responding. Five rats were trained with schedules in which the durations of consecutive intervals increased arithmetically as each interval was completed (either 6-s or 12-s steps for different subjects). The response patterns that emerged with extended training (90 sessions) indicated that performances had come under temporal control. Postreinforcement pausing increased as a function of the interval duration, the pauses were proportional to the prevailing duration, and the likelihood of the first response within an interval increased as the interval elapsed. To assess the resistance of these patterns to disruption, subjects were trained with a schedule that generated high response rates and short pauses (variable ratio). When the progressive-interval schedule was reinstated, pausing was attenuated and rates were elevated, but performances reverted to earlier patterns with continued exposure. The results indicated that temporal control by progressive-interval schedules, although slow to develop, is similar in many respects to that for fixed-interval schedules.     

Within-session Changes In Responding During Autoshaping And Automaintenance Procedures

Four pigeons were exposed to autoshaping procedures in which an 8-second light on a response key was followed by food. Pecks on the key had no scheduled consequences. Subjects were also exposed to negative automaintenance procedures in which a peck on the illuminated key canceled the following food. The intertrial interval varied from an average of 7 seconds to an average of 232 seconds in different conditions. Rate of responding usually changed within sessions during autoshaping. Responding also changed within sessions for the 1 subject that responded during negative automaintenance. The within-session patterns of responding were flatter, peaked later, and were more symmetrical around the middle of the sessions at lower rates of food presentation, regardless of whether subjects responded on autoshaping, negative automaintenance, or previously reported variable-interval schedules. These results imply that similar variables produce within-session changes in responding during both classical (Pavlovian) and operant conditioning procedures.