Thesis (B.A.)--Harvard University, 2005. / Includes bibliographical references (leaves 55-56). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

The present study was concerned with the development and maintenance of (precurrent) behavior that increases the probability of reinforcement for another (current) behavior. A single-subject methodology was employed. Nine human subjects responded on a computer mouse that contained two buttons. One (current) button was reinforced according to a probability schedule (p = .02 or a minor deviation thereof), Depending on the condition, the other button either had no scheduled consequence (i.e., the precurrent contingency was absent) or increased the probability of reinforcement (p = .08) for current responding for 15 s (i.e., the standard precurrent contingency was present). Generally, with the precurrent contingency absent, precurrent responding quickly dropped to near zero levels ; with the precurrent contingency present, precurrent responding maintained at enhanced levels. Between- and within-subject replications suggest that the precurrent contingency was responsible for the maintenance of precurrent responding. Initial exposure to the precurrent contingency resulted in the acquisition of precurrent responding for four of eight subjects. For the four other subjects, a special conditioning procedure was enployed. which included either: (1) increasing the degree to which a precurrent response raised the probability of reinforcement for current responding; or (2) decreasing the probability of reinforcement for current responding to zero unless a precurrent response had occurred within the previous 15 s. Both of these procedures produced enhanced levels of precurrent responding which eventually maintained when the standard precurrent contingency was reintroduced. For four subjects, a OOD was later imposed onto the precurrent contingency. Specifically, a precurrent response produced a brief timeout followed by the period of enhanced reinforcement probability for current responding. In two cases, the CDD reduced precurrent responding to near zero levels, suggesting that reinforcement for current responses immediately following a precurrent response can play an important role in maintenance. In another experiment, the acquisition of precurrent responding was observed when the OOD was part of the precurrent contingency from the beginning, suggesting reinforcement for current responses immediately following a precurrent response is not necessary for acquisition. Current responding generally occurred at a high stable rate within sessions, between sessions, and between conditions. Efficiency (defined as the proportion of current responses in a session emitted under the enhanced probability state) rarely approached maximal levels and generally did not Improve with extended exposure to the precurrent contingency. Post-session verbal reports were recorded for six subjects. The conditioning and extinction of precurrent responding was demonstrated in the absence of "awareness" of the precurrent contingency. The accuracy of the reports varied both between- and within-subjects, and like efficiency, did not Improve with extended exposure to the precurrent contingency. Some issues considered in the discussion include (1) the role of frequency of contact with the precurrent contingency in acquisition and (2) discriminative control by the reinforcement schedules. Directions for future research are also discussed. / Graduate

This study investigated the role of reinforcement schedule and instructional set in frontalis EMG training. The experiment consisted of four groups participating in 30 minute sessions on three consecutive days. Group conditions were intermittent feedback (alternating 100 second trials), continuous feedback, motivated control and no-treatment control. Excepting the no-treatment controls, each subject was instructed that extra credit points were available contingent on the number of seconds in criterion. An individual criterion based on each subject's initial baseline microvolt level was utilized.

The effects of deadlines in contingency-specifying stimuli among nine 4 to 5 year old children were investigated. Each child was given verbal statements differing in the specified deadline, the delivery of the reinforcer, and the opportunity to respond. The results indicated: (a) statements not specifying deadlines or reinforcers failed to control the children's behavior reliably, (b) specifying deadlines, either immediate or delayed, and immediate reinforcers exerted reliable control over the children's behavior when the opportunity to respond was immediately available, and (c) specifying delayed deadlines or no deadlines and immediate or delayed reinforcers did not reliably control the children's behavior when the opportunity to respond was delayed.

This study analyzed the effects of a training package containing response constraint, self-evaluation, reinforcement, and a fading procedure on written letter components and whole letter writing in four elementary school participants. The effect on accuracy of written components was evaluated using a multiple-baseline-across components and a continuous probe design of components, as well as pre-test, baseline, and post-test measures. The results of this study show that response constraint and self-evaluation quickly improved students' performance in writing components. Fading of the intervention was achieved quickly and performance maintained. Results also show that improvement in component writing improved whole letter and full name writing and letter reversals in the presence of a model were corrected.

The current study consisted of two experiments, both of which were comparisons of choice conditions replicated across four participants. Four typically-developing pre-school children participated in this study. Experiment 1 evaluated participants' preference for choosing consequent stimuli prior to engaging in academic tasks (pre-session choice) versus choosing consequent stimuli each time criterion for reinforcement had been met within the session (within-session choice). In Experiment 2, preference for choice-making was evaluated when outcomes for both choice and no-choice conditions were identical. For two participants, results indicated strong preference for choice-making.

Pigeons worked in a titrating delay match-to-sample (TDMTS) procedure in which selecting the correct comparison stimulus increased the delay between sample offset and comparison-array onset and incorrect comparison selections decreased that delay. Prior research in our lab has shown that the stable adjusted value of the retention interval is a curvilinear function of the observing response requirement. The current study examined the effect of the distribution and predictability of observing response requirements on adjusted retention interval values. The data show that unpredictable observing response requirements were more effective in attenuating the deleterious effects of delay on matching accuracy. The data have implications for our understanding of attending and encoding in performances involving remembering over short temporal durations.

The current study investigated the impact of delivering a jackpot on response rate and response allocation in two domestic dogs. For the purpose of this research, a jackpot was defined as a one-time, within-session increase in the magnitude of reinforcement. Two experiments were conducted to investigate the effects of delivering a jackpot in both single-operant and concurrent schedule procedures. Experiment 1 investigated the impact of a one-time, within-session increase in the magnitude of reinforcement on response rate in a single-operant procedure. Results of Experiment 1 showed no clear change in response rate after the delivery of the jackpot. Experiment 2 investigated the impact of a one-time, within-session increase in the magnitude of reinforcement on response allocation in a concurrent schedule procedure. Results of Experiment 2 showed an increase in response allocation to the jackpotted contingency in both subjects. These results suggest that a jackpot, as defined here, has no effect in single-operant procedures while having an effect in concurrent schedule procedures. These effects are similar to those reported in the magnitude of reinforcement literature.

The present study was designed to examine the relationship between the success of self-reinforcement (as defined by its effectiveness in increasing a given response) and a specific aspect of positive self-esteem that would seem most clearly related to the effectiveness of self-reinforcement, valuing one’s own opinions and judgements highly. Self-esteem implies a positive feeling or attitude about oneself. One factor involved in the acquisition of this positive attitude is the level of the individual’s confidence in the legitimacy of his own opinions. The more confident a person is that his opinions are of value, the more likely it is he will have a high self-esteem.

The purpose of the current study was to examine the effects of using fixed time schedules with different magnitudes of stimulus delivery as treatment for pica. A functional assessment was conducted, which indicated that pica occurred across experimental conditions and was most frequent in the absence of social stimulation or contingencies. A competing stimulus assessment was then conducted to identify stimuli that could potentially compete with pica during NCR. Subsequently, an evaluation of the effects of reinforcer magnitude on NCR as a treatment of pica was conducted. Treatment results indicated that quantity of reinforcer increased the effectiveness of leaner schedules of reinforcer delivery; however, it was not possible to fade the temporal schedule to one that would have been useful in practice. In addition, limitations and future research are outlined.