Stimulus control of free-operant avoidance: The contribution of response rate and incentive relations between multiple-schedule components

The associations formed in the components of a multiple schedule can be classified as (1) stimulus-response (S-R) associations and (2) stimulus-reinforcer (S-S^R) associations. The present experiments sought to determine the individual contribution of these S-R and S-S^R associations to stimulus control by manipulating them independently. Responses postponed shocks by 25 sec in the presence of a tone alone and a light alone in all experiments. The contingencies programmed in the absence of both tone and light established a reference for the S-R and S-S^R associations in tone and in light. All four possible combinations of signalling response increase or decrease together with incentive increase or decrease were studied. Although the influence of the contingencies operating in the absence of tone and light was difficult to detect from response rates in tone or light, presenting tone and light together revealed clear effects. Response rates in tone and light together relative to those in either alone depended upon the contingency operating in the absence of tone and light. Stimulus-response and stimulus-reinforcer associations appeared to counteract each other when in opposition and combine together to enhance each other when in agreement. This suggested that the associations of a stimulus to response and to incentive combine algebraically in determining stimulus control. An algebraic analysis in terms of the S-R and S-S^R associations conditioned to the stimulus elements comprising the training and test stimuli accounted for the observed patterns of data.     

Teaching autistic children to use extra-stimulus prompts

Autistic children often do not transfer from extra-stimulus prompts, and thus do not utilize a frequent learning aid. It has been hypothesized that this is due to stimulus overselectivity; a failure to respond to simultaneous multiple cues. This study was designed to determine if autistic children who initially respond only to single cues can be taught a set to respond to two cues and subsequently utilize an extra-stimulus (pointing) prompt. Four autistic children were pretested to determine if they could learn a complex visual discrimination by either trial and error or an extra-stimulus prompt fading procedure. Since they did not, the children were then taught to respond to two cues through a multiple-cue training procedure and subsequently tested to determine if they could now utilize a pointing prompt. Results indicated that while all four children initially did not transfer from an extra-stimulus (pointing) prompt, they did so subsequent to multiple-cue training. The results are discussed in terms of implications for treatment (remediating overselectivity) and in relation to normal child development.     

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.     

Perceiving subjective contours during early childhood

The perception of subjective contours in visual displays that characteristically produce them among adults was studied for children between 3 and 6 years. Evidence for visually creating subjective contours was derived in two ways: (a) by means of direct perception, and (b) by means of recognition of the typically completed shape from among members of a matching series. With both procedures, there were significant age-related contours. A majority of 3-year-olds showed at least one instance of figural completion based on direct perception, and their average recognition performance was 60%. By 5 years, all children provided a clear indication that they had completed at least one figure by means of subjective contours, and their recognition accuracy was 100%. The overall findings provide age-related information that must be accounted for by theories of perceptual development; in particular, those dealing with pictorial perception.     

Relational responses in tests of transposition with Rhesus monkeys

Three adult Rhesus monkeys (Macaca mulatta), one with nonrelated discrimination learning experience and two experimentally naive, were trained to discriminate between two simultaneously presented stimuli differing only in height. After exceeding the learning criteria on a VR 4 reinforcement schedule and considerable overtraining, subjects were tested for transposition. Both upward and downward and near and far tests were administered to determine the effects of distance from the original training pair on the amount of transposition. In these tests, each of the 24 stimulus pairs contained one or more novel stimuli. Training trials were interpolated to avoid extinction effects and measures were taken to avoid motivational deficits or differential rewards during testing. All three subjects responded relationally at far as well as near distances from the original training pair. Stimulus generalization, on the basis of increments of association, was found to be an inferior explanation for these data. Slight decrements on far tests can be better explained in terms of the learning-performance distinction.     

Learned taste aversions in rats as a function of delay,speed, and duration of rotation

Rats fed a saccharin solution and then rotated on a turntable showed an aversion to the saccharin solution on later testing. In the first experiment, the rats learned to avoid saccharin with delays of as much as 9 hr between drinking the saccharin and the start of rotation. The second experiment showed that the critical determinant of aversiveness of rotation was number of rotations. The rats avoided saccharin as much after rotation at high speeds for short durations as after rotation at low speeds for long durations.     

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.     

Problem solving in semantically rich domains: An example from engineering thermodynamics

Recent research on human problem solving has largely focused on laboratory tasks that do not demand from the subject much prior, task-related information. This study seeks to extend the theory of human problem solving to semantically richer domains that are characteristic of professional problem solving. We discuss the behavior of a single subject solving problems in chemical engineering thermodynamics. We use as a protocol-encoding device a computer program called SAPA which also doubles as a theory of the subject's problem-solving behavior. The subject made extensive use of means-ends analysis, similar to that observed in semantically less rich domains, supplemented by recognition mechanisms for accessing information in semantic memory.     

Reinforced practice and reduction of different kinds of fears in adults and children

The purpose of this study was to determine whether or not fears with different origins, course and chronicity could be reduced by a common treatment program. A number of therapeutic procedures that had been experimentally demonstrated to be individually important in prior behavior modification studies with neurotic disorders were combined into a single therapeutic program called ‘reinforced practice.’ The combined elements were: graduated and repeated practice in approaching actual phobic stimuli: reinforcement for gains in performance; feedback of measurable progress; and instructions designed to arouse expectations of gradual success. In each of four experiments involving four different fears, namely fear of heights, snakes and electric shock in adults, and fear of darkness in young children, Ss who expeienced the ‘reinforced practice’ procedure improved their performance by a significant and substantial margin as compared to untreated control Ss. These results suggest that regardless of different etiologies, regardless of whether or not the fears are ‘rational’ or ‘irrational,’ and regardless of whether or not the fears are transitory or long lasting, the same treatment procedure can be equally effective in reducing escape-avoidance behavior.     

Control of selective echolalia via the instatement of a general alternative response

Treatment for echolalic responding has been limited to the training of a small number of correct responses and limited stimulus verbalizations by the experimenter, leaving the possibility that the introduction of novel stimuli could result in the reoccurrence of echolalia. In the present study an 11-year-old severely retarded male's echolalic responding to questions that he could not answer correctly was controlled by instating a general alternative response, “I don't know.” The subject continued to respond correctly to questions that he could answer. indicating that the general alternative response had been appropriately discriminated. A Baseline. Treatment. DRO. Treatment design indicated that the subject's echolalic responding, as well as the appropriate use of the general alternative response, was under experimental control. Generalization of the experimental results to the subject's regular day-care setting was accomplished by having the staff verbally punish all echolalic responses and then restate the question to the subject until a non-echolalic answer had been emitted. Implications of these findings and suggestions for combining previous treatment procedures for echolalia with the general alternative response procedure were offered.     

Critical procedural variables related to the physiological effects of progressive relaxation: a review.

Twenty-five investigations of the physiological effects of progressive relaxation training were classified according to whether relaxation was found to be superior or equivalent to control conditions. The two sets of studies differed significantly on number of training sessions and in the use of taped vs live administration of training, and they tended to differ in the use of normal vs patient samples. The likelihood of producing significant physiological reductions via progressive relaxation appears to be greater when multi-session, subject-controlled training is conducted with subjects for whom physiological activity contributes to a presenting. clinical problem.