EFFECTS OF A PROCEDURE DERIVED FROM THE OVERCORRECTION PRINCIPLE ON MANIPULATED AND NONMANIPULATED BEHAVIORS

Positive practice overcorrection has been shown to be effective in reducing stereotypic self-stimulatory behaviors displayed by retarded and autistic individuals. In addition, the procedure also may increase the occurrence of appropriate behavior through intensive practice. In the present study, several stereotypic and one appropriate behavior (appropriate toy play) displayed by two autistic children were measured before and during treatment by a positive practice in appropriate toy play overcorrection procedure. Overcorrection was introduced for each of the targeted inappropriate behaviors in succession for both children. Results showed that overcorrection reduced all stereotypic behaviors displayed by both children. In addition, one subject displayed marked increases in the behavior practised during overcorrection, appropriate toy play, relative to its baseline rate of occurrence. The results indicate that for some individuals, overcorrection may be effective in teaching and motivating appropriate forms of behavior as well as in reducing stereotypy.     

Effects of d-amphetamine and caffeine on schedule-controlled and schedule-induced responding.

The effects of d-amphetamine and caffeine were studied on rates and patterns of lever pressing and schedule-induced licking under fixed-interval schedules of food pellet presentation. In addition, the effects of caffeine were studied on lever pressing and licking under a multiple fixed-ratio fixed-interval schedule. Caffeine reduced mean overall rates of licking at lower doses than it reduced mean overall rates of pressing under the fixed-interval schedules, but the effects of caffeine on both licking and lever pressing depended largely on the control rate of responding. d-Amphetamine reduced mean overall rates of lever pressing and licking at about the same dose, but the effects of d-amphetamine also were a function of the control rate of responding.     

Test-retest reliability of retrospective self-reports in three populations of alcohol abusers

The reliability of alcohol abusers' retrospective self-reports was evaluated using a time-line follow-back interview technique. Independent groups of male subjects were interviewed in three different treatment settings (outpatient,n=12; inpatient,n=12; residential,n=12) on two separate occasions to assess the test-retest reliability of their self-reports of daily drinking and related events occurring 1 year prior to treatment. Correlational and scatterplot analyses generally showed a high correlation and low discrepancy between the two sets of interview responses for all groups. However, since some population differences were found in the reliability of reports for some variables, further research is needed to delineate the conditions under which reliable and valid retrospective self-reports can be obtained from different populations of alcohol abusers.This research was supported, in part, by Grant No. AA07072 from the National Institute on Alcohol Abuse and Alcoholism to Vanderbilt University.     

Precurrent contingencies: Behavior reinforced by altering reinforcement probability for other behavior

The present study explored the effects of a precurrent contingency in which one (precurrent) activity increased the reinforcement probability for another (current) activity. Four human subjects responded on a two-key computer mouse. Each right-key press was reinforced (points exchangeable for money) with .02 probability. In one condition (no precurrent contingency), pressing the left key had no scheduled consequence; in another condition (precurrent contingency), pressing the left key increased the reinforcement probability for right-key responding to .08 for 15 s. Initial exposure to the precurrent contingency resulted in acquisition of precurrent left-key responding for 3 subjects, but for the 4th subject a special contingency was required. Right-key responding occurred at a high stable rate across the conditions. Changeovers to left-key responding dropped to near zero when the precurrent contingency was absent and were maintained at enhanced levels when the precurrent contingency was present. Contacts with the left key consisted of short response runs. Right-key responses were more frequently emitted within 15 s of a left-key response when the precurrent contingency was present, an efficient adaptation to the contingency. Continued research on precurrent behavior may produce insights into complex phenomena such as autoclitics and self-control.     

Response-rate differences in variable-interval and variable-ratio schedules: An old problem revisited

In Experiment 1, a variable-ratio 10 schedule became, successively, a variable-interval schedule with only the minimum interreinforcement intervals yoked to the variable ratio, or a variable-interval schedule with both interreinforcement intervals and reinforced interresponse times yoked to the variable ratio. Response rates in the variable-interval schedule with both interreinforcement interval and reinforced interresponse time yoking fell between the higher rates maintained by the variable-ratio schedule and the lower rates maintained by the variable-interval schedule with only interreinforcement interval yoking. In Experiment 2, a tandem variable-interval 15-s variable-ratio 5 schedule became a yoked tandem variable-ratio 5 variable-interval x-s schedule, and a tandem variable-interval 30-s variable-ratio 10 schedule became a yoked tandem variable-ratio 10 variable-interval x-s schedule. In the yoked tandem schedules, the minimum interreinforcement intervals in the variable-interval components were those that equated overall interreinforcement times in the two phases. Response rates did not decline in the yoked schedules even when the reinforced interresponse times became longer. Experiment 1 suggests that both reinforced interresponse times and response rate–reinforcement rate correlations determine response-rate differences in variable-ratio 10 and yoked variable-interval schedules in rats. Experiment 2 suggests a minimal role for the reinforced interresponse time in determining response rates on tandem variable-interval 30-s variable-ratio 10 and yoked tandem variable-ratio 10 variable-interval x-s schedules in rats.     

Effects of fixed and variable ratios on human behavioral variability.

The effect that ratio schedules of reinforcement had upon variability of responding was investigated in college students. Subjects were paid $0.02 contingent upon completion of eight presses, distributed in any combination across two push buttons; 256 different sequences were possible. Sequence emission was reinforced according to fixed- and variable-ratio schedules. Ratio requirements of 1, 2, 4 and 8 were presented in alternate components of a multiple schedule. The variability engendered by variable-ratio schedules was also compared to that engendered by fixed ratios. Variability increased with ratio size, irrespective of whether the schedule requirement was fixed or variable. The data demonstrate the similarity between the determinants of human and nonhuman variability, and they illustrate the role of ratio size in determining variability in operant behavior.     

REDUCTION OF SELF-INJURIOUS HAND MOUTHING USING RESPONSE BLOCKING

We evaluated a response-blocking procedure for reducing the self-injurious hand mouthing of 2 adults with profound disabilities. The procedure reduced mouthing in both cases. The results suggest research is warranted to delineate the behavioral process responsible for the effect of response blocking and to determine the procedure's long-term utility.     

SELF-ADMINISTERED WRITTEN PROMPTS TO TEACH HOME ACCIDENT PREVENTION SKILLS TO ADULTS WITH BRAIN INJURIES

This study evaluated the use of written checklists and task analyses as self-administered prompts to teach home accident prevention skills to 4 adults with brain injuries. Subsequent to baseline, participants used written checklists that identified potential in-home hazards but did not prompt behaviors necessary for hazard remediation. Written individualized task analyses, incorporating specific behavioral steps for correcting hazards that participants had failed to remediate during the checklist phase, were used to prompt appropriate responding when necessary. These were subsequently faded to transfer stimulus control to the natural conditions. A multiple probe technique across participants and settings was used. Results indicated that the checklist alone was sufficient to increase appropriate responses to many of the potential hazards. Individualized task analyses, when needed, resulted in appropriate remediation of all potential hazards. Generalization to untrained potential hazards occurred to some degree for all participants. Follow-up results showed that most skills trained were maintained over a 1-month period.     

Rehearsing for confrontation

Social confrontation is a particular kind of communication episode which may be initiated when one actor signals another actor that his or her behavior has violated (or is violating) a rule or expectation for appropriate conduct within the relationship or situation (Newell & Stutman, 1988). This paper explores the decision, structure and process of rehearsing for confrontation. Intensive interviews with 75 actors followed by a questionnaire administered to 99 others revealed that confronters maintain two strands of confrontative goals: strategic and performance goals. Strategic goals for confronters include (a) influence, (b) catharsis, (c) relational maintenance, (d) retribution, and (e) enhanced understanding of the other. While these goals lead to different tactical outcomes, actors also hold intentions related to performance goals. Two performance goals are of central concern to some actors: (a) the desire to be argumentatively complete, and (b) the desire to maintain the position of the confronter rather than the confrontee. An analysis of the data revealed that differences in goal configurations guided both the decision to rehearse and the process of this rehearsal.     

Changes in Multidigit Synergies and Their Feed-Forward Adjustments in Multiple Sclerosis

The authors explored the changes in multidigit synergies in patients with multiple sclerosis (MS) within the framework of the uncontrolled manifold hypothesis. The specific hypotheses were that both synergy indices and anticipatory synergy adjustments prior to the initiation of a self-paced quick action would be diminished in the patients compared to age-matched controls. The MS patients and age-matched controls (n = 13 in both groups) performed one-finger and multifinger force production tasks involving both accurate steady-state force production and quick force pulses. The patients showed significantly lower maximal finger forces and a tendency toward slower force pulses. Enslaving was increased in MS, but only in the lateral fingers (index and little). Indices of multifinger synergies during steady-state force production were lower in MS, mainly due to the lower amount of intertrial variance that did not affect total force. Anticipatory synergy adjustments were significantly delayed in MS. The results show that MS leads to significant changes in multidigit synergies and feed-forward adjustments of the synergies prior to a quick action. The authors discuss possible contributions of subcortical structures to the impaired synergic control.