Exchange delays and impulsive choice in adult humans.

Choice responding by adult humans in a discrete-trial task was examined as a function of conditions that manipulated either the delay to point delivery or the delay between points and their exchange for money. In point-delay conditions, subjects chose between an "impulsive" alternative that provided a small amount of points immediately and a "self-control" alternative that provided a larger amount of points delayed by 15, 30, or 60 s. Points were exchanged for money immediately following the session. Subjects preferred the self-control alternative. In exchange-delay conditions, subjects chose between a small amount of points exchangeable for money immediately following the session and a larger amount of points exchangeable for money after 1 day, 3 weeks, or 6 weeks. A self-control preference observed for all subjects in the 1-day exchange-delay condition reversed to exclusive impulsive preference for 4 of the 6 subjects when choice conditions involved exchange delays of 3 or 6 weeks. These results show that human choice is sensitive to the manipulation of exchange delays and that impulsive preference can be obtained with exchange delays on the order of weeks.     

The effect of token reinforcement on McCarthy Scale performance for white preschoolers of low and high social position

In Study 1, the effect of making tokens contingent on correct performance of low social position preschoolers on the McCarthy Scales of Children's Abilitieswas examined. Preschoolers in a token reinforcement group scored significantly higher (mean=8 IQ points) than subjects in a control group. In Study 2, the effect of tokens on McCarthyresults was examined as a function of social position in a 2×2 design. The high social position control group scored significantly above the low social position control. The low social position token reinforcement group, however, performed as well as both the high social position control and token reinforcement groups. Use of systematic reinforcement contingencies to reduce test error is discussed.     

USING REINFORCEMENT-BASED METHODS TO ENHANCE MEMBERSHIP RECRUITMENT IN A VOLUNTEER ORGANIZATION

The present study employed reinforcement-based methods to induce existing members to recruit new members to join a chamber of commerce. Three interventions took place during June and July of 3 successive years. The investigators trained chamber leaders to use reinforcement methods (e.g., contingent tokens) to reinforce recruitment and dues collections. All three interventions produced substantial increases in their targets.     

THE EFFECTS OF CONTINGENT AND NONCONTINGENT ATTENTION ON SELF-INJURY AND SELF-RESTRAINT

Self-restraint and self-injurious behavior (SIB) are two responses that can sometimes be members of the same functional response class (i.e., maintained by the same contingency). In such cases, a single treatment should be effective for both responses. In this investigation, we examined the effects of providing attention (the presumed reinforcer) both noncontingently and contingent upon either SIB or self-restraint. Results were consistent with our hypothesis that both responses were maintained by attention and suggested that noncontingent reinforcement was a potentially effective treatment.     

A PRELIMINARY PROCEDURE FOR PREDICTING THE POSITIVE AND NEGATIVE EFFECTS OF REINFORCEMENT-BASED PROCEDURES

In the current investigation, a modification was made to the preference assessment described by Pace, Ivancic, Edwards, Iwata, and Page (1985) to predict the effects of stimuli when used in a differential-reinforcement-of-other-behavior (DRO) schedule for 2 clients with severe self-injurious behavior (SIB) and profound mental retardation. Based on the results of the preference assessment, three types of stimuli were identified: (a) high-preference stimuli associated with high rates of SIB (HP/HS), (b) high-preference stimuli associated with relatively lower rates of SIB (HP/LS), and (c) low-preference stimuli associated with low rates of SIB (LP/LS). Consistent with the results of the preference assessment, the DRO schedule with HP/HS stimuli resulted in increased SIB, and the DRO schedule with LP/LS stimuli resulted in no changes in SIB. HP/LS stimuli were demonstrated reinforcers but did not result in a change in SIB when used in a DRO schedule. Thus, the stimulus preference assessment may be useful clinically in some situations for predicting both the beneficial and the negative side effects of stimuli in DRO procedures.     

Effects of cocaine on briefly signaled versus completely signaled delays to reinforcement.

Key pecking by 4 pigeons was maintained by a multiple schedule consisting of two variable-interval 60-s schedules wherein each food presentation followed a nonresetting 27-s delay that was either briefly signaled at its outset or completely signaled. Brief-signal duration was adjusted so that response rates maintained by the briefly and completely signaled delays of reinforcement were similar. In general, acute administration of small to intermediate doses (0.3 to 3.0 mg/kg) of cocaine produced either small increases in response rates in both components or no change, and larger doses (5.6 to 13.0 mg/kg) decreased response rates. Chronic (i.e., daily) cocaine administration (10.0 mg/kg) resulted in tolerance to the rate-decreasing effects in both components. Cocaine's effects were generally similar whether delays were completely or briefly signaled. Discontinuation of cocaine administration and subsequent removal of the delay signals also had similar effects in both components of the multiple schedule. Taken together, these results are consistent with the view that the two types of delay signals were equally effective in maintaining responding during the variable-interval schedules.     

Changeover behavior and preference in concurrent schedules

Pigeons were trained on a multiple schedule of reinforcement in which separate concurrent schedules occurred in each of two components. Key pecking was reinforced with milo. During one component, a variable-interval 40-s schedule was concurrent with a variable-interval 20-s schedule; during the other component, a variable-interval 40-s schedule was concurrent with a variable-interval 80-s schedule. During probe tests, the stimuli correlated with the two variable-interval 40-s schedules were presented simultaneously to assess preference, measured by the relative response rates to the two stimuli. In Experiment 1, the concurrently available variable-interval 20-s schedule operated normally; that is, reinforcer availability was not signaled. Following this baseline training, relative response rate during the probes favored the variable-interval 40-s alternative that had been paired with the lower valued schedule (i.e., with the variable-interval 80-s schedule). In Experiment 2, a signal for reinforcer availability was added to the high-value alternative (i.e., to the variable-interval 20-s schedule), thus reducing the rate of key pecking maintained by that schedule but leaving the reinforcement rate unchanged. Following that baseline training, relative response rates during probes favored the variable-interval 40-s alternative that had been paired with the higher valued schedule. The reversal in the pattern of preference implies that the pattern of changeover behavior established during training, and not reinforcement rate, determined the preference patterns obtained on the probe tests.     

ASSESSMENT AND TREATMENT OF DESTRUCTIVE BEHAVIOR MAINTAINED BY STEREOTYPIC OBJECT MANIPULATION

In the current investigation, 2 participants with mental retardation displayed property destruction and stereotypy, and both responses involved the same materials (e.g., breaking and tapping plastic objects). Three experiments were conducted (a) to indirectly assess the functions of these two responses, (b) to determine their relation to one another, and (c) to develop a treatment to reduce the more serious behavior, property destruction. In Experiment 1, previously destroyed materials were either present or absent, and their presence reduced property destruction but not stereotypy. In Experiment 2, matched toys (ones that produced sensory stimulation similar to stereotypy) were either present or absent, or were replaced by unmatched toys (for 1 participant). Matched toys produced large reductions and unmatched toys produced small reductions in property destruction and stereotypy. In Experiment 3, attempts to pick up undestroyed objects were either blocked or not blocked while matched toys were continuously available. Response blocking reduced property destruction (and attempts), prevented stereotypy, and increased manipulation of matched toys. These results suggest that the two aberrant responses formed a chain (e.g., breaking and then tapping the object), which was maintained by the sensory consequences (e.g., auditory stimulation) of the terminal response, and that previously destroyed material or matched toys made the initial response (property destruction) unnecessary.     

Effects of differential reinforcement on the behavior and self-esteem of children with emotional and behavioral disorders

Students in a residential special school for children with emotional and behavioral disorders participated in a study designed to reduce their levels of inappropriate behavior. The residential care staff rated the students' behavioral problems and their class teachers rated their overt self-esteem pre and post intervention. In addition, the students completed self-ratings of their self-esteem. The students were divided into two groups, experimental and control. A multiple baseline across behaviors design was used to assess behavioral changes in the experimental group. Both groups received tangible rewards to the same level but only the experimental group received them contingent upon behaving appropriately. Results showed that the experimental group students made substantial reductions in their levels of inappropriate behavior, which were maintained at a three-month followup. Also, ratings of their behavioral problems by residential child care staff suggested that this improvement in behavior had generalized beyond the classroom to the residential setting. However, no significant differences were found between the pre- and post-intervention ratings of their self-esteem or teacher ratings of their overt self-esteem.