Goal-oriented, flexible use of numerical operations by monkeys

Previous studies have shown that elementary aspects of numerical abilities have developed in non-human primates. In the present study, we explored the potential for the development of a novel ability in the use of numerical operations by macaque monkeys (Macaca fuscata): adequate selection of a series of numerical actions toward achieving a behavioral goal. We trained monkeys to use a pair of devices to selectively add or subtract items to/from a digital array in order to match a previously viewed sample array. The monkeys determined whether to add or subtract on the basis of the feedback about numerosity given to the monkeys, which was displayed as an outcome of each step of the numerical operation. We also found that monkeys adapted flexibly to changes in the numerical rule that determined the relationship between device use and numerical operation. Our model analysis found that the numerosity-based model was a better fit for the monkeys’ performance than was the reward-expectation-based model. Such a capacity for goal-oriented selection of numerical operations suggests a mechanism by which monkeys use numerical representations for purposeful behaviors.     

Resolving individual Shockley partials of a dissociated dislocation by STEM

A practical method was developed to image detailed features of defects in a crystal using STEM. This method is essentially a STEM version of the conventional CTEM g/3g weak beam dark field (WBDF) method. The method was successfully applied to resolving individual Shockley partials of a dissociated dislocation in a Cu-6.44at.%Al alloy.     

Evaluation of fixed momentary dro schedules under signaled and unsignaled arrangements

Fixed momentary schedules of differential reinforcement of other behavior (FM DRO) generally have been ineffective as treatment for problem behavior. Because most early research on FM DRO included presentation of a signal at the end of the DRO interval, it is unclear whether the limited effects of FM DRO were due to (a) the momentary response requirement of the schedule per se or (b) discrimination of the contingency made more salient by the signal. To separate these two potential influences, we compared the effects of signaled versus unsignaled FM DRO with 4 individuals with developmental disabilities whose problem behavior was maintained by social-positive reinforcement. During signaled FM DRO, the experimenter presented a visual stimulus 3 s prior to the end of the DRO interval and delivered reinforcement contingent on the absence of problem behavior at the second the interval elapsed. Unsignaled DRO was identical except that interval termination was not signaled. Results indicated that signaled FM DRO was effective in decreasing 2 subjects' problem behavior, whereas an unsignaled schedule was required for the remaining 2 subjects. These results suggest that the response requirement per se of FM DRO may not be problematic if it is not easily discriminated.     

Assessment and treatment of foot-shoe fetish displayed by a man with autism

Results of a functional analysis indicated that a man diagnosed with autism engaged in bizarre sexual behavior in the presence of women wearing sandals. Several treatments proved to be ineffective or impractical. By contrast, a response-interruption/time-out procedure quickly eliminated the problem behavior in multiple settings.     

ASSESSMENT OF STEREOTYPIC AND SELF-INJURIOUS BEHAVIOR AS ADJUNCTIVE RESPONSES

Certain responses of both humans and nonhumans appear to be maintained indirectly by intermittent reinforcement schedules and have been referred to collectively as adjunctive behavior. Although basic research has examined adjunctive behavior extensively, relatively few studies have been conducted with humans, particularly those with developmental disabilities who often engage in frequent and varied stereotypic behavior. This study assessed possible adjunctive characteristics of self-injurious and stereotypic behaviors using a multielement design containing two types of control conditions. Four subjects who engaged in both self-injurious behavior and stereotypy participated after variables maintaining their self-injury were identified via functional analyses. Each day, subjects were exposed to three 15-min sessions in random order: (a) noncontingent presentation of food on a fixed-time schedule (e.g., FT 30 s), (b) a massed-reinforcement (food) control, and (c) a no-reinforcement control. A variety of fixed-time schedules were examined during different experimental phases. Results of this preliminary study suggested that self-injury was not induced by intermittent reinforcement schedules, whereas the stereotypic behavior of some individuals showed characteristics of adjunctive behavior. The importance of research on adjunctive behavior and suggestions for future studies are discussed.     

TRANSFER OF BEHAVIORAL FUNCTION AS A CONTRIBUTING FACTOR IN TREATMENT RELAPSE

When relapse occurs following successful treatment to reduce problem behavior, it is often attributed to inconsistent implementation of maintenance programs. Although less likely, another potential cause for relapse is a change in the behavior's maintaining contingency over time. To examine this possibility, additional assessment was conducted with 4 individuals who were rereferred to a day-treatment program due to recurrence of their self-injurious behavior (SIB) 2 months to 2 years following successful treatment. In each case, the original treatment had been developed and implemented based on the outcome of functional analysis assessments. For 1 subject, results of a second functional analysis were consistent with those from the original assessment, indicating that the function of her SIB had remained unchanged. For the other 3 subjects, results of the second assessment suggested that their SIB had acquired new or additional functions. These findings indicate that factors other than program inconsistency can lead to relapse, and that clinical revaluation for such cases should include a current functional analysis to determine if new treatment components are needed.     

EFFECTS OF REINFORCEMENT CHOICE ON TASK RESPONDING IN INDIVIDUALS WITH DEVELOPMENTAL DISABILITIES

The effects of reinforcement choice on task performance were examined with 6 individuals who had been diagnosed with severe to profound mental retardation. Five highly preferred items were identified for each participant via stimulus preference assessments. Participants then were exposed to choice and no-choice conditions that were alternated within reversal and multielement designs. During choice sessions, participants were permitted to select between two preferred stimuli contingent on responding. During no-choice sessions, the therapist delivered a single item contingent on responding. Preference for the stimuli was held constant across conditions by yoking the items delivered during no-choice sessions to those selected during the immediately preceding choice sessions. All participants exhibited similar rates of responding across choice and no-choice conditions. These findings indicate that for individuals with severe disabilities, access to choice may not improve task performance when highly preferred items are already incorporated into instructional programs.     

PROTECTIVE EQUIPMENT: CONTINUOUS AND CONTINGENT APPLICATION IN THE TREATMENT OF SELF-INJURIOUS BEHAVIOR

This study evaluated the use of protective equipment in treating self-injurious behavior (SIB) exhibited by three retarded persons. In Experiment 1, the equipment was first applied continuously during 20-min sessions in individual multiple baseline designs across settings. Results showed substantial reductions in head hitting, eye gouging, and hand biting. Brief periods of time-out with the protective equipment were later made contingent on SIB and combined with a differential reinforcement procedure. Reduced levels of SIB was maintained with all subjects. Additionally, the amount of time during which the equipment was applied decreased as the SIB diminished. Experiment 2 evaluated the use of contingent protective equipment (the final condition in Experiment 1) when applied directly in the subjects' living uints during the day. During Experiment 2, SIB remained at or below the levels found at the termination of Experiment 1. Finally, in an effort to assess the long-term effectiveness of the procedure, responsibility for implementation was given to the staff who were typically assigned to provide therapy to the subjects. Follow-up probe observations conducted up to 104 days after termination of the final experimental condition showed continued low levels of both SIB and equipment usage. Results of these experiments suggest that contingent protective equipment and differential reinforcement may be effective in reducing chronic self-injury.     

False-positive maintenance of self-injurious behavior by access to tangible reinforcers.

Results of a functional analysis indicated that the hand mouthing of a woman with developmental disabilities was maintained by multiple sources of control (sensory stimulation and access to a leisure item). Further assessment revealed that access to several other items also produced high rates of hand mouthing. However, direct observation conducted in the woman's home indicated that none of these items was delivered contingent upon hand mouthing. When the consequence observed most frequently in the home was incorporated into the functional analysis, rates of hand mouthing were no higher than they were during an alone condition. We concluded that hand mouthing, although maintained by automatic reinforcement, was also susceptible to social contingencies when exposed to them during assessment, thereby producing a partially false-positive outcome.