Substitution effects in a generalized token economy with pigeons

Pigeons made repeated choices between earning and exchanging reinforcer‐specific tokens (green tokens exchangeable for food, red tokens exchangeable for water) and reinforcer‐general tokens (white tokens exchangeable for food or water) in a closed token economy. Food and green food tokens could be earned on one panel; water and red water tokens could be earned on a second panel; white generalized tokens could be earned on either panel. Responses on one key produced tokens according to a fixed‐ratio schedule, whereas responses on a second key produced exchange periods, during which all previously earned tokens could be exchanged for the appropriate commodity. Most conditions were conducted in a closed economy, and pigeons distributed their token allocation in ways that permitted food and water consumption. When the price of all tokens was equal and low, most pigeons preferred the generalized tokens. When token‐production prices were manipulated, pigeons reduced production of the tokens that increased in price while increasing production of the generalized tokens that remained at a fixed price. The latter is consistent with a substitution effect: Generalized tokens increased and were exchanged for the more expensive reinforcer. When food and water were made freely available outside the session, token production and exchange was sharply reduced but was not eliminated, even in conditions when it no longer produced tokens. The results join with other recent data in showing sustained generalized functions of token reinforcers, and demonstrate the utility of token‐economic methods for assessing demand for and substitution among multiple commodities in a laboratory context.     

Reinforcer Variation in a Token Economy

We evaluated whether generalized conditioned reinforcers mitigate the effects of satiation with an individual with intellectual disabilities. Previous research indicates that generalized conditioned reinforcers are not sensitive to satiation effects. However, this effect has not been investigated on varying classes of backup reinforcers. First, we established a highly preferred (HP) edible as a reinforcer. Then, we provided presession access to the HP edible, and, in a multi‐element comparison, the participant could either earn tokens for only the HP edible, for edibles that were similar to the HP edible, for edibles that were dissimilar to the HP edible, or earn no tokens. A decreasing trend in responding for the HP edible was observed following presession access. Furthermore, the participant completed the task at a high rate when backup reinforcers were dissimilar to the HP edible. Results suggest that varying the classes of stimuli that are used as backup reinforcers may increase the effectiveness of generalized conditioned reinforcers. Copyright © 2015 John Wiley & Sons, Ltd.     

Using progressive ratio schedules to evaluate tokens as generalized conditioned reinforcers

The properties of operant reinforcers are dynamic and dependent on a number of variables, such as schedule and effort. There has been sparse research on the generalized conditioned properties of token reinforcement. We evaluated leisure items, edible items, and tokens using a progressive ratio schedule with three children with diagnoses of ASD and developmental delays. The highest break points occurred during the token reinforcement condition for two out of three participants, but response rates tended to be higher with edibles. We then evaluated the effects of presession access to edibles on the break points of edible items and tokens with two participants. Break points decreased only in the edible reinforcement condition, and the participants chose to work for leisure items rather than edibles when presession access to edibles was in place. These findings suggest that the tokens functioned as generalized conditioned reinforcers.     

The effects of token reinforcement on attending in a young child with autism

The benefits of token economies have been widely established, however there are very few empirical studies on the effects of token reinforcement on the behavior of young children with autism. The establishment of conditioned reinforcers such as tokens may be important in interventions for children with autism. Token reinforcement was used to increase the attending behavior of a young child with autism during discrete trials instruction for academic and communication skills. A reversal design showed that token reinforcement sustained attending only when the back‐up reinforcer was available and was accessed immediately. The results extend and corroborate findings on token reinforcement reported in other applied settings and are also consistent with findings from basic research on conditioned reinforcement. Copyright © 2006 John Wiley & Sons, Ltd.     

Determinants of pigeons' choices in token-based self-control procedures

Four pigeons were exposed to a token-based self-control procedure with stimulus lights serving as token reinforcers. Smaller-reinforcer choices produced one token immediately; larger-reinforcer choices produced three tokens following a delay. Each token could be exchanged for 2-s access to food during a signaled exchange period each trial. The main variables of interest were the exchange delays (delays from the choice to the exchange stimulus) and the food delays (also timed from the choice), which were varied separately and together across blocks of sessions. When exchange delays and food delays were shorter following smaller-reinforcer choices, strong preference for the smaller reinforcer was observed. When exchange delays and food delays were equal for both options, strong preference for the larger reinforcer was observed. When food delays were equal for both options but exchange delays were shorter for smaller-reinforcer choices, preference for the larger reinforcer generally was less extreme than under conditions in which both exchange and food delays were equal. When exchange delays were equal for both options but food delays were shorter for smaller-reinforcer choices, preference for the smaller reinforcer generally was less extreme than under conditions in which both exchange and food delays favored smaller-reinforcer choices. On the whole, the results were consistent with prior research on token-based self-control procedures in showing that choices are governed by reinforcer immediacy when exchange and food delays are unequal and by reinforcer amount when exchange and food delays are equal. Further, by decoupling the exchange delays from food delays, the results tentatively support a role for the exchange stimulus as a conditioned reinforcer.     

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.     

ESTABLISHING OPERATIONS AND REINFORCEMENT EFFECTS

Positive reinforcement procedures have had a major impact on educational programs for the developmentally disabled; nevertheless, variation in reinforcer effectiveness both within and across individuals is a common phenomenon. This study examined one class of variables—establishing operations—that might influence the effectiveness of reinforcers. Five developmentally disabled adult males participated. Responding on one of two motor tasks—switch closure or block placement—was assessed during baseline, satiation, and deprivation conditions with respect to three classes of consequences: small food items, music, and social praise. Deprivation and satiation conditions were constructed so as not to alter significantly the normal course of events in a subject's day. For example, food deprivation entailed scheduling sessions just prior to a subject's regular lunch, and social deprivation involved limiting a subject's access to social interaction for 15 minutes, during which time the subject had access to an assortment of other activities. Results showed that each stimulus class functioned as reinforcement with different degrees of effectiveness during satiation versus deprivation conditions. These results are discussed in light of previous research on enhancement of reinforcer efficacy as well as the assessment and identification of functional reinforcers, and implications are presented for future research and client habilitation.     

An analysis of the value of token reinforcement using a multiple-schedule assessment

Token systems are widely used in clinical settings, necessitating the development of methods to evaluate the reinforcing value of these systems. In the current paper, we replicated the use of a multiple-schedule reinforcer assessment (MSA; Smaby, MacDonald, Ahearn, & Dube, 2007) to evaluate the components of a token economy system for 4 learners with autism. Token systems had reinforcing value similar to primary reinforcers for 2 of the 4 learners, but resulted in lower rates of responding than primary reinforcers for the other 2 learners. Differentiated responding across learners may warrant variation in clinical recommendations on the use of tokens. The results of this study support formal assessment of token system effectiveness, and the MSA procedure provides an efficient method by which to conduct such assessments.     

An experimental evaluation of tokens as conditioned reinforcers in retarded children

Since the publication of experimental reports by Wolfe (1936) and Cowles (1937), that tokens could be established as conditioned reinforcers, many accounts have appeared on the implementation of token systems in human subjects. Tokens have been successfully used as prosthetic motivational devices in a great variety of situations and subjects, such as retarded children (Birnbrauer, Wolf, Kidder and Tague, 1965), adult psychotics (Ayllon and Azrin, 1969), delinquent children and adolescents (Tyler, 1967; Phillips and Wolf, 1968), low achievers in schools (Clark, Lachowicz and Wolf, 1968), emotionally disturbed children (Hewett, Taylor and Artuso, 1969) and in normal classroom settings (O'Leary, Becker, Evans and Saudargas, 1969). In these reports, administration of tokens usually produced an increase in the frequency of desirable social and productive behavior. However, none of these studies showed that the effect of the tokens depended on their role as conditioned reinforcers based on the standard exchange systems being used. No assessment was provided about the separate contribution of the social reinforcement operations involved in dispensing tokens in a social setting.A suggestion about the possible confounding effects of social reinforcement in token administration comes from the failure to establish token systems in subjects who are partially unresponsive to social reinforcement (Hamblin et al., 1970; Ribes and Souza e Silva, in preparation). The present research was conducted with the aim of isolating the effects of conditioned reinforcement as such—apart from those produced by the social reinforcement provided in the delivery of tokens.     

RISKY CHOICE IN PIGEONS: PREFERENCE FOR AMOUNT VARIABILITY USING A TOKEN-REINFORCEMENT SYSTEM

Pigeons were given repeated choices between variable and fixed numbers of token reinforcers (stimulus lamps arrayed above the response keys), with each earned token exchangeable for food. The number of tokens provided by the fixed‐amount option remained constant within blocks of sessions, but varied parametrically across phases, assuming values of 2, 4, 6, or 8 tokens per choice. The number of tokens provided by the variable‐amount option varied between 0 and 12 tokens per choice, arranged according to an exponential or rectangular distribution. In general, the pigeons strongly preferred the variable option when the fixed option provided equal or greater numbers of tokens than the variable amount. Preference for the variable amount decreased only when the alternatives provided widely disparate amounts favoring the fixed amount. When tokens were removed from the experimental context, preference for the variable option was reduced or eliminated, suggesting that the token presentation played a key role in maintaining risk‐prone choice patterns. Choice latencies varied inversely with preferences, suggesting that local analyses may provide useful ancillary measures of reinforcer value. Overall, the results indicate that systematic risk sensitivity can be attained with respect to reinforcer amount, and that tokens may be critical in the development of such preferences.     

A Preliminary Examination of a Vocal Generalized Conditioned Reinforcer

Generalized conditioned reinforcers (GCRs) in the form of tokens are commonly used in behavioral treatment. However, it is possible for non‐tangible consequences to also function as GCRs. For example, a vocal stimulus (e.g., good job) associated with completion of a work task, access to preferred actives, and peer interaction could function as a GCR. The purpose of this study was to examine the effects of pairing a vocal stimulus with multiple edible reinforcers on the Frequency math problem completion. The results suggest that a vocal statement paired with an array of four back‐up reinforcer functioned as a GCR for completing math problems for two typically developing children identified as having minor deficits in math skills. Copyright © 2015 John Wiley & Sons, Ltd.     

Autoshaping the pigeon's gape response: acquisition and topography as a function of reinforcer type and magnitude.

The pigeon's key-pecking response is experimentally dissociable into transport (head movement) and gape (jaw movement) components. During conditioning of the key-pecking response, both components come under the control of the conditioned stimulus. To study the acquisition of gape conditioned responses and to clarify the contribution of unconditioned stimulus (reinforcer) variables to the form of the response, gape and key-contact responses were recorded during an autoshaping procedure and reinforcer properties were systematically varied. One group of 8 pigeons was food deprived and subgroups of 2 birds each were exposed to four different pellet sizes as reinforcers, each reinforcer signaled by a keylight conditioned stimulus. A second group was water deprived and received water reinforcers paired with the conditioned stimulus. Water- or food-deprived control groups received appropriate water or food reinforcers that were randomly delivered with respect to the keylight stimulus. Acquisition of the conditioned gape response frequently preceded key-contact responses, and gape conditioned responses were generally elicited at higher rates than were key contacts. The form of the conditioned gape was similar to, but not identical with, the form of the unconditioned gape. The gape component is a critical topographical feature of the conditioned key peck, a sensitive measure of conditioning during autoshaping, and an important source of the observed similarities in the form of conditioned and consummatory responses.     

Positive conditioned suppression: conditioned suppression using positive reinforcers as the unconditioned stimuli

Research has revealed the phenomenon of conditioned suppression in which the rate of responding is reduced during a stimulus that is paired with noncontingent shock. The present study replicated this procedure, but used noncontingent positive reinforcers instead of the aversive shock. The lever-pressing responses of rats were reinforced with food or water. While the rats were responding, a stimulus was occasionally presented and paired with the delivery of a noncontingent positive reinforcer, which was either food, water, or brain stimulation for different rats. The result was a reduction in the rate of responding during the conditioned stimulus. This finding shows that conditioned suppression occurs during a signal for reinforcing as well as aversive stimuli.     

Substitutability between conditioned and primary reinforcers in discrimination acquisition.

Rats and pigeons were trained on a series of reversals of a conditional simultaneous discrimination. The percentage of reinforcement for correct trials was varied across reversals. When nonreinforced correct trials produced the same feedback as incorrect trials, the number of errors to reach an acquisition criterion was greater for smaller percentages of reinforcement, but the number of reinforcers required was either approximately constant or smaller for the smaller percentages. When a stimulus paired with food (the conditioned reinforcer) was added on nonreinforced correct trials, both measures were substantially decreased. When the same stimulus was presented, but without a history of food pairing, learning rate was similar to when no stimulus was presented on nonreinforced trials. The results provide direct evidence that conditioned reinforcers may substitute, although imperfectly, for a primary reinforcer, and that pairing with the primary reinforcer is a necessary condition for such substitutability to occur.     

REINFORCER ACCUMULATION IN A TOKEN-REINFORCEMENT CONTEXT WITH PIGEONS

Four pigeons were exposed to a token-reinforcement procedure with stimulus lights serving as tokens. Responses on one key (the token-production key) produced tokens that could be exchanged for food during an exchange period. Exchange periods could be produced by satisfying a ratio requirement on a second key (the exchange-production key). The exchange-production key was available any time after one token had been produced, permitting up to 12 tokens to accumulate prior to exchange. Token accumulation, measured in terms of both frequency (percent cycles with accumulation) and magnitude (mean number of tokens accumulated), decreased as the token-production ratio increased from 1 to 10 across conditions (with exchange-production ratio held constant), and increased as the exchange-production ratio increased from 1 to 250 across conditions (with token-production ratio held constant). When tokens were removed, accumulation decreased markedly compared to conditions with tokens and the same schedules. These data show that token accumulation is an orderly function of token-production and exchange-production schedules, and they are broadly consistent with a unit-price model based on local and global responses per reinforcer.     

THE RELATIVE MOTIVATIONAL PROPERTIES OF SENSORY AND EDIBLE REINFORCERS IN TEACHING AUTISTIC CHILDREN

We compared the effects of sensory and edible reinforcers on resistance to satiation in three autistic children while learning visual discrimination tasks. Within-subject designs were used to compare a single sensory reinforcer with a single edible reinforcer and to compare multiple sensory reinforcers with multiple edibles. Results indicated that multiple sensory reinforcers maintained responding over more trials than did multiple edible reinforcers; however, the use of single sensory reinforcers and single edibles resulted in about equal numbers of trials to satiation. Both multiple and single sensory reinforcers produced higher percentages of correct responses than edible reinforcers. The findings are discussed in terms of the advantages of sensory reinforcers in teaching autistic children.     

Dynamic changes in reinforcer effectiveness: satiation and habituation have different implications for theory and practice

Reinforcers lose their effectiveness when they are presented repeatedly. Early researchers labeled this loss of effectiveness as satiation without conducting an experimental analysis. When such an analysis is conducted, habituation provides a more precise and empirically accurate label for the changes in reinforcer effectiveness. This paper reviews some of the data that suggest that habituation occurs to repeatedly presented reinforcers. It also argues that habituation has surprisingly different implications than satiation for theory and practice in behavior analysis. For example, postulating that habituation occurs to repeatedly presented reinforcers suggests ways for maintaining the strength of an existing reinforcer and for weakening the strength of a problematic reinforcer that differ from those implied by an account in terms of satiation. An habituation account may also lead to different ways of conceptualizing the regulation of behavior. For example, habituation may be a single-process contributor to the termination of behaviors that are usually attributed to satiation (e.g., ingestive behaviors such as eating and drinking), fatigue (e.g., energetic behaviors such as running), the waning of attention (e.g., cognitive behaviors such as studying), and pharmacodynamic factors (e.g., drug taking).     

Effectiveness of DRO tokens in decreasing disruptive behavior in the classroom with five multiply handicapped children

In this study the effectiveness of differential reinforcement of other behavior (DRO) with tokens was assessed in the treatment of various topographies of disruptive behavior in the classroom with five children who were multiply handicapped. Prior to implementation of the treatment, reinforcer assessment was conducted to identify items to be used as back-up reinforcers. Data were analyzed using time-series analysis. Results show that DRO tokens were highly effective in decreasing disruptive behavior of all participants. ©1997 by John Wiley & Sons, Ltd.     

TOKEN REINFORCEMENT DURING THE INSTATEMENT AND SHAPING OF FLUENCY IN THE TREATMENT OF STUTTERING

The value of token reinforcement in the instatement and shaping of fluency was examined in an intensive treatment program for adult stutterers. Experiment 1 examined the effect of removing the tangible back-up reinforcers for the token system and found that clients' performance in the program was equally good with or without these back-up reinforcers, suggesting that a strict token economy may not be crucial to rapid progress through treatment. Experiment 2 compared contingent and noncontingent token reinforcement, while controlling for some variables that may have confounded the results of earlier research, and found no difference in clients' performance. Experiment 3 examined the effect of the entire removal of token reinforcement. Performance was found to be no worse under a “no tokens” system than under a system of tokens with back-up reinforcers. It is argued that in a highly structured treatment program where many other reinforcers are operating, token reinforcement may be largely redundant. Clinical and theoretical implications of the findings are discussed.     

Establishing praise as a conditioned reinforcer: Pairing with one versus multiple reinforcers

Praise and other forms of attention may not function as reinforcers for the behavior of children with autism. Previous research demonstrated that contingently pairing praise with reinforcers (response stimulus) can establish praise as a conditioned reinforcer. We evaluated a procedure for establishing praise as a generalized conditioned reinforcer (pair praise with four reinforcers) and compared it with a procedure to establish praise as a conditioned reinforcer (pair praise with one reinforcer). We compared the two conditions in a reversal design with “praise” and “no programmed consequence” conditions rapidly alternated after pairing phases. With three out of five participants with autism, responding in the “pair‐with‐four” condition showed higher levels of responding or more increasing trends compared with that in “pair‐with‐one” condition. We also replicated previous contingent pairing research with two participants in a multiple baseline across participants design. A limitation was the absence of manipulating motivating operations in assessing the efficacy of praise as a generalized conditioned reinforcer. Nevertheless, these data contribute to the research on establishing praise as a reinforcer, and we recommend directions for future research.