Control of preference in children by conditioned positive reinforcement

A preference measure was employed with children to evaluate the conditioned positive reinforcing function of a stimulus that preceded reinforcement. A match-to-sample procedure was arranged in which subjects could respond to either the form or color dimension of a compound sample stimulus. Intermittent token reinforcement was provided equally for color and form matches. Two stimuli were employed (Stimulus A and Stimulus B), each consisting of a distinctive tone and colored light. One of these stimuli (the paired stimulus) preceded each token delivery, and the other did not (nonpaired stimulus). The paired stimulus was dependent upon each response to one match dimension, and the nonpaired stimulus followed each response to the other dimension. Three of the five subjects responded primarily to the dimension that was followed by the paired stimulus. This effect was obtained regardless of which stimulus (A or B) was paired and on which match dimension (color or form) the paired stimulus was dependent. These results were unaltered by discontinuing the nonpaired stimulus. The other two subjects demonstrated consistent preferences for the form dimension and Stimulus A, respectively.     

Conditional discrimination learning in the pigeon

Four pigeons received conditional discrimination training in which reinforcement contingencies were related to specific combinations of color and form, but were unrelated to either color or form considered separately. During discrete-trial training, each response in the presence of two of four color-form displays produced reinforcement and terminated the trial; responding to the other two displays was never reinforced, and each such response prolonged the particular trial on which it occurred. Subsequently, the subjects received multiple-schedule training in which responding to either of the displays previously associated with reinforcement was now reinforced on a variable-interval schedule, and extinction was the schedule again correlated with the other two displays. After differential responding to the stimuli was clearly evident, intensity of the combination displays was changed in subsequent training sessions. Complex stimulus control was generally maintained across variation in intensity, although there were temporary disruptions in performance associated with onset of some of the intensity changes. Finally, a component-stimulus test revealed considerably more responding to the forms than to the colors.     

Category discrimination by pigeons using five polymorphous features

Eight pigeons were trained to discriminate between sets of color photographs of natural scenes. The scenes differed along five two-valued dimensions (site, weather, camera distance, camera orientation, and camera height), and all combinations of the feature values were used. One value of each dimension was designated as positive, and slides containing three or more positive feature values were members of the positive stimulus set. Thus, each feature had an equal, low, correlation with reinforcement, and all features had zero correlations with each other. Seven of the 8 pigeons learned this discrimination, and their responding came under the control of all five features. Within the positive and negative stimulus sets, response rates were higher to stimuli that contained more positive feature values. Once discrimination had been achieved, reversal training was given using a subset of the slides. In this subset, only a single feature was correlated with reinforcement. All pigeons learned this reversal successfully and generalized it to additional photographs with the same feature content. After reversal, the original reinforcement contingencies were reinstated, and training was continued using all the slides except those that had been used in reversal. Reversal generalized to these slides to some extent. Analysis of the response rates to individual slides showed that, compared with prereversal training, only the feature that had been subjected to reversal contingencies showed a reversed correlation with response rate. The remaining features showed the same correlation with response rate as they had before reversal training. Thus, reversal on some members of a category following category discrimination training led to generalization to stimuli within the category that were not involved in the reversal, but not to features that were not reversed. It is therefore inappropriate to refer to the pigeons as learning a concept.     

The development of stimulus control with and without a lighted key

In two experiments, the effect of an illuminated response key on the acquisition of stimulus control by an airflow stimulus was assessed. In the first experiment, pigeons were given nondifferential training with airflow emerging from behind the response key in one of three conditions of illumination: trained to peck a lighted key, trained to peck an unlighted key with a houselight present, trained to peck a key in total darkness. After 10 days of training on a variable-interval schedule of reinforcement, all subjects were given a generalization test on airflow velocity. The gradients for subjects trained in the dark were sharp, while those for subjects trained in lighted conditions were shallow. In the second experiment, the effect of an irrelevant keylight on the acquisition of an airflow velocity discrimination was assessed. Two groups of pigeons were trained to discriminate two airflow velocities. One group was trained with a lighted response key and the other was trained to peck the response key in total darkness. The dark-trained subjects acquired the discrimination more rapidly. The results demonstrate that the acquisition of stimulus control by airflow with either a differential or nondifferential training procedure can be overshadowed by keylight.     

Change in the relative contributions of habit and working memory facilitates serial reversal learning expertise in rhesus monkeys

Functionally distinct memory systems likely evolved in response to incompatible demands placed on learning by distinct environmental conditions. Working memory appears adapted, in part, for conditions that change frequently, making rapid acquisition and brief retention of information appropriate. In contrast, habits form gradually over many experiences, adapting organisms to contingencies of reinforcement that are stable over relatively long intervals. Serial reversal learning provides an opportunity to simultaneously examine the processes involved in adapting to rapidly changing and relatively stable contingencies. In serial reversal learning, selecting one of the two simultaneously presented stimuli is positively reinforced, while selection of the other is not. After a preference for the positive stimulus develops, the contingencies of reinforcement reverse. Naïve subjects adapt to such reversals gradually, perseverating in selection of the previously rewarded stimulus. Experts reverse rapidly according to a win-stay, lose-shift response pattern. We assessed whether a change in the relative control of choice by habit and working memory accounts for the development of serial reversal learning expertise. Across three experiments, we applied manipulations intended to attenuate the contribution of working memory but leave the contribution of habit intact. We contrasted performance following long and short intervals in Experiments 1 and 2, and we interposed a competing cognitive load between trials in Experiment 3. These manipulations slowed the acquisition of reversals in expert subjects, but not naïve subjects, indicating that serial reversal learning expertise is facilitated by a shift in the control of choice from passively acquired habit to actively maintained working memory.     

The use of programmed materials in the analysis of academic contingencies

Programmed handwriting materials were used to examine the effects of different reinforcement contingencies on the academic performance of six public school kindergarten children. The children's responses to these materials provided an educationally relevant dependent variable for the analysis of factors that affected the accuracy of their responses and the attainment of criterion performances. Variations in the complexity of most academic materials, which confound the analysis of contingencies, were eliminated by the programmed sequence so that the differential effects of three reinforcement conditions were observed. The three conditions were: baseline without tokens, tokens contingent on correct writing responses, and noncontingent tokens. It was consistently observed that the children were more accurate when their correct responses produced tokens, and that noncontingent tokens reduced accuracy below baseline levels.     

Social control by adult preference in operant conditioning with children

During daily sessions four institutionalized retardates and four normal, first-grade children each played a two-choice marble dropping game while an adult experimenter sat beside and watched. When one of two colored lights was presented, two tokens were dispensed as soon as the subject dropped a marble, and when the other light was on, one token was dispensed. During choice trials that were interspersed among single-colored trials the subject was required to choose one of the two different colored holes. After the subject developed a preference for the color that earned two tokens, the experimenter stated a preference for the response that earned only one token (i.e., “I like it better when you put it into the —colored hole.”) Six of the eight subjects immediately switched to the response that earned low magnitude reinforcement when the experimenter stated his preference. Only two subjects switched back to the response that earned high magnitude reinforcement when the experimenter left the room. Subjects complied with the experimenter's preference statement regardless of whether or not it also included a negative component (i.e., what the experimenter did not like). There were no systematic differences between mentally retarded and normal subjects.     

The effects of token reinforcement,feedback and response cost on standardized test performance

The primary purpose of the present study was to compare the differential effects of token reinforcement, feedback, and response cost on the test performance of delinquent boys. Eighty students were randomly assigned to three experimental groups and one control group of 20 subjects each. Each experimental group received a standard and a modified administration of the verbal section of the WISC. For the token reinforcement group, the modified WISC administration permitted students to earn tokens contingent on correct responses; the response cost group forfeited tokens contingent on incorrect responses; and the feedback group simply received information regarding the accuracy of each response. The control group received two standard WISC administrations. The primary measure was the difference in verbal I.Q. scores between the standard and modified WISC administrations. Results indicated that the token reinforcement and response cost groups achieved significantly higher scores than the feedback and control groups. No significant differences were found between the token reinforcement and response cost groups nor between the feedback and control groups. The implications of these findings for clarifying the relationship between motivational condition and test performance are discussed.     

The choices and preferences of nursery school children

After a period of equal reinforcement for choices of any job revealed which of 10 jobs each of 24 preschool children preferred and did not prefer, token payment became dependent on particular choices. Some children received tokens only for choosing previously non-preferred jobs, others for choosing previously preferred jobs. When tokens depended on choosing the nonpreferred jobs, those came to be preferred. When tokens depended on choosing the preferred jobs, the preferences were strengthened. The effects were replicated both within and between subjects, except in the case of one boy who consistently avoided token pay.     

Functional lateralization, interhemispheric transfer and position bias in serial reversal learning in pigeons (Columba livia)

In the present study we investigated lateralization of color reversal learning in pigeons. After monocular acquisition of a simple color discrimination with either the left or right eye, birds were tested in a serial reversal procedure. While there was only a slight and non-significant difference in choice accuracy during original color discrimination, a stable superiority of birds using the right eye emerged in serial reversals. Both groups showed a characteristic ‘learning-to-learn’ effect, but right-eyed subjects improved faster and reached a lower asymptotic error rate. Subsequent testing for interocular transfer demonstrated a difference between pre- and post-shift choice accuracy in pigeons switching from right to left eye but not vice versa. This can be accounted for by differences in maximum performance using either the left or right eye along with an equally efficient but incomplete interocular transfer in both directions. Detailed analysis of the birds’ response patterns during serial reversals revealed a preference for the right of two response keys in both groups. This bias was most pronounced at the beginning of a session. It decreased within sessions, but became more pronounced in late reversals, thus indicating a successful strategy for mastering the serial reversal task. Interocular transfer of response patterns revealed an unexpected asymmetry. Birds switching from right to left eye continued to prefer the right side, whereas pigeons shifting from left to right eye were now biased towards the left side. The results suggest that lateralized performance during reversal learning in pigeons rests on a complex interplay of learning about individual stimuli, stimulus dimensions, and lateralized response strategies. Received: 4 June 1999 / Accepted after revision: 18 August 1999     

Attention to components or compounds as a factor in discrimination transfer performance.

Prior to being tested with standard reversal or extradimensional (ED) shift procedures, two groups of mentally retarded subjects (MA: 4 to years) were pretrained using two different methods. The Component group received two problems which could be solved easily only by attending to the form components. The Compound group was trained on two problems requiring attention to compound color-form cues. It was assumed that the two solution modes would carry over to the third problem, which was for both groups a standard form discrimination with color variable and irrelevant within settings. The fourth problem was either an ED shift or a reversal. The Component group learned reversal faster than ED shift whereas the opposite was true for the Compound group. Subproblem analyses of ED shift performance showed dependent settings for the Component group and independent settings for the Compound group. Results are consistent with the view that compound and component solutions of discriminative problems are achieved by attention to the abstract dimensions of compounds or components and that attention to either of these dimensions can be trained at higher or lower developmental levels even though the salience of the compound dimension may be initially greater for lower level subjects.     

A CROSS-CULTURAL STUDY OF RECOGNITION MEMORY FOR FACES1

The hypothesis that subjects would show superior memory for faces of members of their own ethnic group compared with those of a different ethnic group was tested in a cross-cultural experiment. Thirty two African and 32 European subjects were presented with coloured photographs of ten black Africans and ten white Europeans, with the instruction to try to remember them. Twenty four hours later, the subjects were presented with the same photographs shuffled with an equal number of new photographs of Africans and Europeans, and were asked to identify those they had seen before. The index d' was used as a measure of recognition. As predicted, European subjects were superior at recognising European faces compared with African faces, and African subjects were superior at recognising African faces compared with European faces. Response bias data indicated that European subjects had a differential response bias for the photographs of the two ethnic groups, but African subjects did not differ in their bias towards the two ethnic groups. African subjects did, however, show differential response bias for sex within the European faces. The results were discussed in terms of perceptual discrimination and stereotyping.     

Humans’ responses to novel stimulus compounds and the effects of training

Twenty-four college students participated in an experiment with stimulus compounds. Subjects learned to discriminate color stimuli that correlated with varying probabilities of reinforcement. Reinforcement consisted of points. For all subjects, two colors signaled a .80 reinforcement probability, and two others signaled a .20 probability. For compound-trained subjects, a fifth compound stimulus (composed of a high-probability color and a low-probability color) was correlated with a .10 reinforcement probability. During testing, interspersed probe trials required subjects to choose between two alternatives: a compound stimulus and either one of its constituent stimuli. Compound-untrained subjects preferred the compound over either individual stimulus, thus showing response summation. However, compound-trained subjects, having had experience with an exemplar compound, showed significantly lower choice proportions for a test compound, indicating that subjects’ responding to novel stimulus compounds is modifiable by experience with a single similar compound.     

An analysis of timeout and response cost in a programmed environment

A group of mildly retarded adolescents with high rates of antisocial behavior was exposed to two parameters of timeout and response cost within the context of a programmed environment. For five of the six subjects, the two higher values (30 tokens response cost or 30 min timeout) were significantly more suppressive than the lower values (five tokens or 5 min). For the one remaining subject, there was a strong relationship in the opposite direction. Also, the timeout and response cost of higher value became increasingly more suppressive over time, whereas those of lower value did not. There were few appreciable differences between the timeout and response cost of similar magnitude. A discussion of these results is presented in support of the notion that the functional aversiveness of timeouts (and response costs) appears to be critically dependent upon interactions with the environmental conditions in which they are implemented and the reinforcement histories of the subjects.     

An evaluation of simultaneous presentation and differential reinforcement with response cost to reduce packing

We evaluated the effects of multiple treatment procedures, including simultaneous presentation of preferred foods, on the packing behavior of a 9-year-old girl with autism. A reversal design was used to assess the effects of differential reinforcement with response cost alone and with simultaneous presentation. In addition, simultaneous presentation was assessed independent of differential reinforcement with response cost. Results indicated that simultaneous presentation reduced packing and that differential reinforcement with response cost was not necessary to maintain these reductions. Results are discussed in terms of the use of simultaneous presentation for packing as an alternative to consequence manipulations.     

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.     

THE EFFECTIVENESS OF REINFORCEMENT,RESPONSE COST,AND MIXED PROGRAMS ON CLASSROOM BEHAVIORS1

Six elementary school children served as subjects in an experiment comparing the relative effectiveness of (1) token reinforcement, in which children received tokens for attending and for correct arithmetic performance; (2) response cost, in which children received “free” tokens at the start of a period but lost them for inattention and for arithmetic performance below a specified level; and (3) a combination of both token reinforcement and response cost. During training, the six subjects received all three procedures in counterbalanced sequence. The effects of the three procedures were assessed by a within-subject comparison divided into three phases: (i) baseline, (ii) training, (iii) withdrawal of tokens. Introduction of the three token procedures markedly increased the two dependent measures. However, there were no differences across the procedures in the amount of change produced in either attending behavior or arithmetic performance. During baseline, the subjects averaged 29% attending behavior and 6.4 correct problems. These levels increased to 85% for attending behavior and 11.4 correct problems for arithmetic performance during training. Removal of all token procedures significantly decreased attending behavior (to an average of 65%), but produced a nonsignificant reduction in arithmetic performance (to an average of 7.6 correct problems). There was evidence that this lack of differential effects of the three token procedures was not due to an inability to discriminate among them. Furthermore, the subjects were evenly divided in their preference for the three procedures.     

Token reinforcement, choice, and self-control in pigeons.

Pigeons were exposed to self-control procedures that involved illumination of light-emitting diodes (LEDs) as a form of token reinforcement. In a discrete-trials arrangement, subjects chose between one and three LEDs; each LED was exchangeable for 2-s access to food during distinct posttrial exchange periods. In Experiment 1, subjects generally preferred the immediate presentation of a single LED over the delayed presentation of three LEDs, but differences in the delay to the exchange period between the two options prevented a clear assessment of the relative influence of LED delay and exchange-period delay as determinants of choice. In Experiment 2, in which delays to the exchange period from either alternative were equal in most conditions, all subjects preferred the delayed three LEDs more often than in Experiment-1. In Experiment 3, subjects preferred the option that resulted in a greater amount of food more often if the choices also produced LEDs than if they did not. In Experiment 4, preference for the delayed three LEDs was obtained when delays to the exchange period were equal, but reversed in favor of an immediate single LED when the latter choice also resulted in quicker access to exchange periods. The overall pattern of results suggests that (a) delay to the exchange period is a more critical determinant of choice than is delay to token presentation; (b) tokens may function as conditioned reinforcers, although their discriminative properties may be responsible for the self-control that occurs under token reinforcer arrangements; and (c) previously reported differences in the self-control choices of humans and pigeons may have resulted at least in part from the procedural conventions of using token reinforcers with human subjects and food reinforcers with pigeon subjects.     

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.     

AN INVESTIGATION OF THE EFFECTS OF TOKEN REINFORCEMENT ON DIVERGENT VERBAL RESPONDING1

The effect of token reinforcement on three classes of divergent verbal responding to verbal stimulus items from three measures of the Wallach-Kogan Creativity test was examined. The subjects consisted of two “gifted”, two “average”, and two “learning disabled” children from a public-school setting. The design utilized both an intra-subject and inter-subject multiple-baseline design with a reversal design added. Tokens were dispensed contingent upon the number of appropriate verbal responses to each stimulus item, i.e., a continuous schedule of reinforcement was used—one token per appropriate response. Interobserver agreement on “appropiateness” was 993%. The tokens could be used to “purchase” items listed in a “menu” format (e.g., ball and jacks—100 tokens). Consistently large effects of token reinforcement were observed, without generalization of effect across the three classes of behaviors, or conditions. These results support the works of Goetz and Baer (Journal of Applied Behavior Analysis, 1973, 6 , 209–217), Goetz and Salmonson (Behavior Analysis and Education, G. Semb, (Ed.), University of Kansas, 1972, 53–61), and Maloney and Hopkins (Journal of Applied Behavior Analysis, 1973, 6 , 425–434). Implications lie in continued experimental analysis of behavior approach to the concept called “creativity”. Additionally, implications are made in classroom application of assessing and intervening in the area of divergent responding for children with deficits in those areas.