Response discriminative and reinforcement factors in stimulus control of performance on multiple and chained schedules of reinforcement

Discriminative control of the response rates of two groups of rats was equated by training them to cease bar pressing in light-out no-tone ( + ) and to respond during tone and light. Multiple-schedule subjects received food at the same rate for responding during tone or light as for nonresponding in + . For the chained-schedule subjects responding in tone or light only produced + where food was received for nonresponding. In extinction tests multiple-schedule subjects emitted approximately twice the responses to tone-plus-light as to tone or light presented individually (additive summation). The rats trained on the chained schedule, in which the tone and light each controlled substantial response rates but were never paired with food, showed no summation when the tone and light were presented together. The results indicate that discriminative control of response rates and reinforcement differences between schedule components determine stimulus control.     

Stimulus control and delayed reinforcement

Pigeons were tested for generalization along the line-orientation dimension, after being trained on various two-component multiple schedules. The first component contained either a variable-interval 1-min schedule of immediate reinforcement or an extinction schedule and was associated with a plain white key (S1). The second component contained a variable-interval 1-min schedule of delayed reinforcement and was associated with a black line on a white background (S2). The major results showed that (a) decremental gradients were obtained around the stimulus associated with the delayed reinforcement component when S1 was associated with extinction, but that incremental gradients were obtained when S1 was associated with immediate reinforcement, (b) the subjects' pretraining did not affect the generalization gradients if sufficient training on the terminal multiple schedule was provided, and (c) changing the S1 schedule from immediate reinforcement to extinction produced behavioral contrast if reinforcement was delayed for 10 sec during S2, but not if it was delayed for 20 sec.     

Reversal and nonreversal shifts in autistic children

Reversal and nonreversal shifts in nineteen 2- to 14-year-old autistic children were studied. Each child was taught both a reversal and nonreversal shift discrimination task. The reversal shift condition entailed teaching the child to respond to one (the S+) of a pair of stimuli during training and subsequently reversing the S+ during testing. The nonreversal shift condition consisted of teaching the child two unrelated discriminations during training and testing. The results indicated that the older autistic children did better on reversal shifts than younger children who did better on nonreversal shifts. These findings are consistent with those for normal children.     

Stimulus control of responding by response-reinforcer temporal contiguity

The stimulus properties of brief disruptions in response-reinforcer temporal contiguity were investigated using a discrete trial conditional discrimination procedure. Key pecking (nondelay) or key pecking followed by a brief interval of nonpecking (delay) in the sample component produced a stimulus change (choice component). Pecks in the choice component to one of two alternatives resulted in food or blackout, conditional upon which response requirement was met in producing the choice component. A baseline condition, in which key pecking always produced the choice component and correct choices were arranged randomly, alternated with experimental conditions that included nondelay and delay values of either 0.2, 0.5, or 1.0 sec between the last key peck and the initiation of the choice component. All subjects accurately discriminated brief temporal delays between a response and stimulus change, with choice accuracy increasing for three of four subjects as the temporal disruption in contiguity increase. Implications of the research for the study of delayed reinforcement, response-independent reinforcement, and the discrimination of causality are discussed.     

The program for academic survival skills (pass): Effects on student behavior and achievement

The effects of the Program for Academic Survival Skills (PASS), a group behavior management program, on behavioral observation data and standardized achievement test measures were investigated. Fifty-four of the 96 selected low-achieving, low-survival-skill students of normal IQ were assigned to an experimental condition in which their teachers used PASS. The remaining 42 were assigned to a control condition. Results indicated PASS produced significant gains in survival skills during its operation and one week following program termination in both reading and mathematics periods across grades 1–3. Findings for achievement indicated a significant gain for first-grade experimentals only in reading, with a similar but nonsignificant gain for first-grade mathematics.     

Effects of US-Presentation and CS-termination contingencies on avoidance extinction following partial and continuous reinforcement

The present study assessed the role of both the US-presentation (punishment) and CS-termination contingencies on the maintenance of the shuttlebox avoidance responding in gerbils following acquisition under either partial reinforcement (PR) or continuous reinforcement (AV). Following PR, a stronger relationship obtained between delay of CS termination CR frequency than was found between delay of punishment and extinction performance. Following AV training, however, delay of CS termination and delay of punishment were equally effective determinants of avoidance extinction. These results were interpreted in terms of both the enhanced efficacy of the CS-termination contingency, possibly due to its increased informational value, and the attenuation of punishment suppression in PR-trained Ss.     

Preference as a function of the correlation between stimuli and reinforcement outcomes

Pigeons' preferences for stimuli that were to varying degrees correlated with outcomes were studied in two experiments using a concurrent-chain procedure. The pigeons chose between two terminal links, each ending with food reinforcement and with blackout on half of the trials. In the first experiment, one terminal link (nonpredictive or unreliable link) provided stimuli completely uncorrelated with the outcomes while the other terminal link (predictive or reliable link) provided stimuli that were, to varying degrees, correlated with these outcomes. All pigeons showed increasing preferences for the predictive link as the reliability of the stimuli in that link increased. In the second experiment, stimuli in both terminal links were differentially correlated with the outcomes. The pigeons again preferred the more reliably correlated terminal link. The relation between these results and the delay-reduction hypothesis and conditioned reinforcement account is noted. The behavioral value of predictive stimuli may lie in their permitting the organism to more effectively apportion its time between interim activities and terminal responses.     

Reinforcement rate and force proportional reinforcement

The research examines the consequences of making two reinforcement contingencies simultaneously available for the same bar-pressing response. Specifically, two experiments are described which concern the effects of reinforcement rate upon force proportional reinforcement (FPR). In Experiment 1, reinforcement rate was constrained by combining differential reinforcement of low rate with a force-proportional reinforcement contingency. The group of rats exposed to this regimen eventually showed a significant increase in response force compared to control groups. Experimental vs control response rates were not significantly different. In Experiment 2, reinforcement rate was affected through the expedient of relating the probability of obtaining a single pellet to the response force. The group for which the probability-force relationship was discontinuous came to exert higher forces than either a group for which the relationship was fairly continuous or an ordinary variable ratio control group. Response rate was significantly higher for the control group.     

The ambiguous-cue problem: The effects of reduced similarity between trials and the schedule of reinforcement

In a series of seven experiments pigeons were trained on the two-choice ambiguous-cue problem that contains PA and NA trials. On PA trials choice of P (the positive stimulus) was reinforced and choice of A (the so-called ambiguous stimulus) was not reinforced; on NA trials choice of A was reinforced and choice of N (the negative stimulus) was not reinforced. When the two types of trials were distinguished by only the presence of P or N and each trial was terminated by one response, subjects quickly attained high levels of performance on NA trials but showed only chance levels of performance on PA trials. PA performance was markedly improved when a variety of additional stimuli distinguished the two types of trials and when a variety of schedules of intermittent reinforcement were employed; these manipulations had little effect on NA performance.     

Stochastic transitivity and the unidimensional control of choice

A concurrent-chains paradigm was used to test three models of preference for schedules of reinforcement. Each model assumes choice to be a monotonic function of values on a single dimension (“simple scalability”). For choices involving variable-interval and fixed-interval schedules, this dimension is assumed to be an harmonic average of the interreinforcement intervals; for choices involving fixedinterval and fixed-ratio schedules, the dimension is the time to reinforcement irrespective of response rate; for choices involving different combinations of rate and duration of reinforcement, the dimension is the rate of “reinforcement-time”, or the product of the two parameters. Each model implies a strong form of transitivity (“functional equivalence”), which held for half the subjects (that half exclusively sensitive to the reinforcement variable specified by the model). An alternative unidimensional model which implies a weaker form of transitivity (“weak binary utility model”) was consistent with the preferences of all subjects. This model states that a single factor controls the direction of preferences but not necessarily the exact choice probability, as simple scalability assumes.     

Noticing and responding in a discrimination based on a distinguishing element

In learning a successive go/no-go discrimination between a positive display consisting of the elements A and B, and negative display consisting of A-alone, pigeons first trained to peck A shift to pecking the distinguishing B element. In order to learn whether or not the shift to B is facilitated by B's function as a signal of the reinforcer, apart from the direct reinforcement of B responses, six arrangements of the elements with respect to the food reinforcer were used. Discrete trials were terminated by a single peck or after 4 sec. The A and B elements were dots of different color. The most critical comparison was between two groups, both of which received no reinforcement for a response directed to B. In one case, B signaled the reinforcer: An A response was reinforced when B was present but not when A appeared alone. In the other, B signaled the absence of a reinforcer: An A response was nonreinforced when B was present, while the response to A-alone was reinforced. During training and in extinction many more reponses were made to B when it signaled the reinforcer than when it signaled its absence. It is concluded that in a discrimination between AB positive and A negative the shift from pecking A to pecking B is facilitated by B's role as a signal for the reinforcer even on trials in which the peck is not made to B. Results from certain other groups showed that, unless pecks shifted to B within the positive display, pecks to A continued on the negative, A-alone trials as well as on the positive AB trials.     

Children's avoidance responses to three probabilities of threatened consequences

Children's avoidance responses were conditioned and then extinguished in a laboratory analog of a social threat situation. Aversive events (story interruptions) were programmed to follow either 100% (group E100) of the signals (threats), 60% (group E60) of the signals, or 20% (group E20) of the signals during acquisition. The subjects could avoid the signal and/or the aversive event by responding with lever presses above criterion level. Results indicated that groups E100 and E60 were generally not different from each other but avoided significantly more interruption and signals and responded at a higher rate than group E20. Groups E100 and E60 both shifted their responding from approximately equivalent probabilities of signal and interruption avoidance to relatively greater avoidance of interruptions during acquisition, and then shifted back to equivalent probabilities of signal and interruption avoidance during extinction. Results were discussed in terms of the function of threats as discriminative stimuli.     

Acquisition and extinction of signaled avoidance as a function of intermittent reinforcement

Signaled, shuttle-box avoidance responding in female rats of the Fischer₃₄₄ strain was examined as a function of four separate contingencies of intermittent reinforcement. In Experiment 1, when avoidance responses during acquisition were reinforced 25% of the time with prompt CS termination, animals responded equally often during acquisition and significantly more often during extinction than animals who received such reinforcement on a 100% schedule. Similar results were found under a trace procedure in Experiment 2 when avoidance responses were reinforced 25% of the time with informational feedback stimuli. In contrast, during Experiment 3, when animals were shocked on only 25% of the trials on which they failed to respond, the level of avoidance responding during both acquisition and extinction was significantly less than it was when animals were shocked on a 100% schedule. Comparable results were found in Experiment 4 when avoidance responses during acquisition averted shock on only 25% of the trials. Thus, intermittent reinforcement contingencies involving response-contingent feedback stimuli and shock have differential effects on avoidance responding during both acquisition and extinction trials under the signaled avoidance procedure.     

A test of causal sequences in two models for development of career-orientation in women

To evaluate the tenability of two causal orderings of variables in the development of career-orientation, responses of 92 college senior women to Need Achievement, Dating Frequency, and Career-Orientation items were analyzed. The postulated orderings were derived from two models: a compensatory model implying that failure in a woman's heterosexual affiliation leads to high nAch which, in turn, produces high C-O; an enrichment model suggesting that a woman's high nAch may lead to high C-O which, in turn, decreases heterosexual affiliation. Criteria for temporal sequences as per the Simon-Blalock correlational procedures rendered the enrichment model more tenable.