Some effects of frustration in a free responding operant situation

In several experiments, rats and pigeons were reinforced on a chained schedule which varied in its second component but which always had a variable interval schedule as its first component. Occasionally, the reward which normally followed responding in the second component was omitted. On these frustrative non-reward occasions responding immediately subsequent to non-reward was sometimes elevated and sometimes depressed. The relevance of the elevation and depression effects to behavioural measures of frustration in the double runway was discussed.     

Elimination of position-biased responding in individuals with autism and intellectual disabilities

Five individuals with autism or other developmental disabilities participated in paired-stimulus preference assessments during repeated baseline probes. All subjects initially showed a pronounced bias by typically selecting the stimulus placed in either the left or right position. Biased responding for 3 subjects was eliminated when training trials were conducted in which a stimulus of known lesser quality was presented as one of the choices. Reinforcer-quality training was unsuccessful for 2 subjects, as was a condition in which reinforcer magnitude was modified to favor unbiased responding. These subjects' biased responding was eliminated only when a correction procedure (repetition of error trials) was implemented.     

Signal duration and suppression of operant responding by free reinforcement

Pigeons were trained on a VI (variable interval) schedule of food presentation with a superimposed schedule of response-independent food. Substantial suppression of the operant response rate occurred when the free food was presented without a signal. When the free food was preceded by a short (4 sec) signal, the degree of suppression was similar to that with unsignaled free food. But when the signal was lengthened to 12 sec, the degree of suppression was substantially reduced. Experiment 3 assessed the effect of signal duration using a baseline schedule of delayed reinforcement, in which contingent reinforcers were themselves preceded by a signal. The signal preceding the free reinforcers was then either the same as or different from this contingent signal. Signal duration effects occurred only when the two types of signals were different. These differences as a function of signal duration have implications for both “context-blocking” and “comparator” interpretations of the effects of noncontingent reinforcement in both Pavlovian and operant procedures.     

The effects of constant vs varied reinforcer presentation on responding by autistic children

The autistic child's characteristic lack of motivation can create considerable problems for educators. Since there is some evidence that stimulus variation may influence motivation, this study was designed to assess the differential effects of constant vs varied reinforcer presentation. Specifically, two questions were addressed: (1) Would there be any differences in the total number of responses emitted by autistic children when the reinforcer was held constant as opposed to varied; and (2) would there be any differences in the interresponse interval for constant vs varied reinforcer presentation? The results clearly demonstrated that the children in this investigation made significantly more and faster responses when the reinforcer presentation was varied as opposed to constant. The results are discussed in terms of the effects of stimulus variation on satiation and implications for teachers of autistic children.     

Effects of reinforcement rate and reinforcer magnitude on choice behavior of humans

Two experiments with human subjects investigated the effects of rate of reinforcement and reinforcer magnitude upon choice. In Experiment 1, each of five subjects responded on four concurrent variable-interval schedules. In contrast to previous studies using non-human organisms, relative response rate did not closely match relative rate of reinforcement. Discrepancies ranged from 0.03 to 0.43 (mean equal to 0.19). Similar discrepancies were found between relative amount of time spent responding on each schedule and the corresponding relative rates of reinforcement. In Experiment 2, in which reinforcer magnitude was varied for each of five subjects, similar discrepancies ranging from 0.05 to 0.50 (mean equal to 0.21), were found between relative response rate and relative proportion of reinforcers received. In both experiments, changeover rates were lower on the long-interval concurrent schedules than on the short-interval ones. The results suggest that simple application of previous generalizations regarding the effects of reinforcement rate and reinforcer magnitude on choice for variable-interval schedules does not accurately describe human behavior in a simple laboratory situation.     

Preratio pausing: effects of an alternative reinforcer on fixed- and variable-ratio responding

Seven rats responding under fixed-ratio or variable-ratio schedules of food reinforcement had continuous access to a drinking tube inserted into the operant chamber. Under different conditions they could drink either tap water or one of two saccharin solutions. In a baseline condition, the drinking bottle was empty. Preratio pausing was observed with both schedules, more so with the fixed-ratio than the variable-ratio schedule, and increasing the concentration of the saccharin solution increased the duration of pausing. Comparisons with baseline performances revealed that the additional pausing was largely, but not entirely, spent drinking. The results support the view that pausing under ratio schedules is a consequence of competition between the scheduled reinforcer and alternative reinforcers that also are available within the experimental environment.     

The effects of satiation and reinforcer develuation on signal-centered behavior in the rat

Two experiments are described which investigate the effects of satiation and reinforcer devaluation on signal-centered behavior in rats. In Experiment 1 lever contacts were established in hungry rats by pairing retractable lever presentations (CS) with response-independent food (UCS). Subsequently, food satiating these subjects significantly reduced the level of CS contact during an extinction test and, in particular, suppressed CS-directed licking and pawing. In Experiment 2 lever contacts which were established by lever-food pairings were suppressed when the food reinforcer was paired with lithium chloride (LiCl) induced illness. In particular, CS-directed licking, sniffing, and orienting were significantly suppressed by these food-LiCl pairings. These results suggest that signal-centered behavior (i) is not simply a manifestation of “conditioned hunger,” (ii) is determined to some extent by the animal's current need state, and (iii) is influenced by the status of specific reinforcer representations.     

Assessing the role of alternative response rates and reinforcer rates in resistance to extinction of target responding when combining stimuli

Studies of behavioral momentum reveal that reinforcing an alternative response in the presence of a target response reduces the rate of target responding but increases its persistence, relative to training the target response on its own. Because of the parallels between these studies and differential‐reinforcement techniques to reduce problem behavior in clinical settings, alternative techniques to reduce problem behavior without enhancing its persistence are being explored. One potential solution is to train an alternative response in a separate stimulus context from problem behavior before combining the alternative stimulus with the target stimulus. The present study assessed how differences in reinforcement contingencies and rate for alternative responding influenced resistance to extinction of target responding when combining alternative and target stimuli in pigeons. Across three experiments, alternative stimuli signaling a response–reinforcer dependency and greater reinforcer rates more effectively decreased the persistence of target responding when combining alternative and target stimuli within the same extinction tests, but not when compared across separate extinction tests. Overall, these findings reveal that differences in competition between alternative and target responding produced by contingencies of alternative reinforcement could influence the effectiveness of treating problem behavior through combining stimulus contexts.     

Effects of choice of stimuli as reinforcement for task responding in reinforcement for task responding in preschoolers with and without developmental disabilities

The effects of choice and no choice of stimuli as reinforcement for task responding were investigated across preschoolers with and without disabilities. Five less preferred stimuli were identified for each participant using a stimulus preference assessment. No differences were found for choice and no-choice conditions when the less preferred stimuli were used as reinforcers.     

The relationship between predictability and problem behavior for students with severe disabilities

Two single-case studies were conducted to examine the extent to which signaled (predictable) and unsignaled (unpredictable) events were associated with changes in the level of problem behavior during instruction. Two students with moderate-to-severe intellectual disabilities and autism participated in the study. Each student was nominated for the study based on a teacher's report that problem behaviors were much more likely when novel or unsignaled events occurred. Functional assessments were conducted with each student and the specific predictability features (signals) associated with low and high levels of problem behavior were identified. Multi-element and reversal designs were employed to examine the extent to which increased predictability was associated with reduced problem behavior. Results supported the use of functional assessment procedures to determine whether signals that provide information about the content, duration, timing, and/or consequences of future events could reduce problem behaviors.     

Minimized tolerance to the suppressive effects of CCK8 on operant responding

This study was designed to determine if tolerance to cholecystokinin octapeptide (CCK8) could be prevented or minimized by spacing injections, and if an appetitive operant conditioning paradigm provides a sensitive baseline to test the effects of CCK8. Male Sprague-Dawley rats were trained to press a lever for water according to a fixed-interval 60-sec schedule of reinforcement. After response rate stabilized, rats were given a series of CCK8 (0.04 mg/kg, ip) injections spaced several days apart. The first injection of CCK8 produced complete response suppression during the 30-min test session, while later injections produced partial or complete suppression. Thus, tolerance to CCK8, as measured by operant response rate, may be minimized if injections are appropriately spaced.     

The effects of a local negative feedback function between choice and relative reinforcer rate

Four pigeons were trained on two-key concurrent variable-interval schedules with no changeover delay. In Phase 1, relative reinforcers on the two alternatives were varied over five conditions from .1 to .9. In Phases 2 and 3, we instituted a molar feedback function between relative choice in an interreinforcer interval and the probability of reinforcers on the two keys ending the next interreinforcer interval. The feedback function was linear, and was negatively sloped so that more extreme choice in an interreinforcer interval made it more likely that a reinforcer would be available on the other key at the end of the next interval. The slope of the feedback function was -1 in Phase 2 and -3 in Phase 3. We varied relative reinforcers in each of these phases by changing the intercept of the feedback function. Little effect of the feedback functions was discernible at the local (interreinforcer interval) level, but choice measured at an extended level across sessions was strongly and significantly decreased by increasing the negative slope of the feedback function.     

Some effects of response-correlated increases in reinforcer magnitude on human behavior

After training under short or long fixed-interval schedules, humans responded under a modified fixed-interval schedule in which magnitude of reinforcement (X or 2X) was minimally correlated with response frequency. Response frequencies that equaled or exceeded a minimum response criterion were followed by the larger reinforcer at the end of the interval; otherwise, the smaller reinforcer was delivered. The modified schedule alternated with the baseline schedule across conditions. In a control condition, the reinforcer magnitudes produced by control subjects were yoked to those of experimental subjects. Experimental subjects, but not control subjects, showed increased responding. In addition to the baseline and modified fixed-interval schedules used in Experiment 1, subjects in Experiment 2 also responded under a second modified fixed-interval contingency in which increases in reinforcer magnitude were more highly correlated with response frequency. Experimental subjects, but not control subjects, showed increased responding under both procedures. Direct comparison of these two procedures showed that the high-correlation procedure produced greater increases in responding than did the low-correlation procedure.     

The effects of differential and lag reinforcement schedules on varied verbal responding by individuals with autism

Variability has been shown to be a reinforceable dimension of behavior. One procedure that has been demonstrated to increase variability in basic research is the lag reinforcement schedule. On this type of schedule, a response is reinforced if it differs from a specified number of previous responses. Lag schedules are rarely used, however, for increasing response variability in applied settings. The purpose of the present study was to investigate the effects of a lag schedule of differential reinforcement on varied and appropriate verbal responding to social questions by 3 males with autism. A reversal design with a multiple baseline across subjects was used to evaluate the effects of the lag schedule. During baseline, differential reinforcement of appropriate responding (DRA) resulted in little or no varied responding. During the intervention, a Lag 1 requirement was added to the DRA (Lag 1/DRA) resulting in an increase in the percentage of trials with varied and appropriate verbal responding for 2 of the 3 participants. In addition, an increase in the cumulative number of novel verbal responses was also observed for the same 2 participants. These results are discussed in terms of reinforcement schedules that support variability, generalization, and potential stimulus control over varied responding.     

Effective instructional procedures for teaching individuals with severe disabilities in motor skills

The purpose was to describe effective instructional procedures used to teach motor skills to individuals with severe disabilities. Five effective instructional procedures supported with experimental data in adapted physical education are identified through the review of literature: (a) response shaping, (b) increasing prompt hierarchy, (c) decreasing prompt hierarchy, (d) constant time delay, and (e) progressive time delay. The characteristics, documentations, guidelines, and recommendations for application of these procedures are described.     

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.     

On the effects of food deprivation and component reinforcer rates on multiple-schedule performance

Six pigeons were used to investigate the effects of varying body weight and component reinforcer rates in two-component multiple variable-interval variable-interval schedules. In Parts 1 and 3 of the experiment, unequal component reinforcer rates were arranged, and body weights were respectively increased and decreased. At 80% ad lib weight, response-rate ratios were closer to unity than reinforcer-rate ratios, but at 100% or more of ad lib weight, response-rate ratios generally equaled reinforcer-rate ratios. In Part 2, component reinforcer-rate ratios were varied over five conditions with the subjects maintained at 100% or more of their ad lib weights, and response-rate ratios matched reinforcer-rate ratios. The data thus support the empirical finding that response allocation in multiple schedules is a function of deprivation. Although this qualitative result is predicted by three models of multiple-schedule performance, only a model that assumes no direct component interaction adequately describes the data.