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Token economies are among the oldest and most successful teaching programs in applied behavior analysis. Despite a rich history of basic and applied research on token systems, there remains a research‐to‐practice gap. Our aim in this paper is to bridge this gap between research and application, by providing evidence‐based recommendations and practical guidelines for application of token reinforcement methods. The recommendations in Part 1 are for building a token economy from the ground up, in learners without a history of token reinforcement, whereas those in Part 2 are concerned with existing token economies without regard to how they were established. Although token economies have proven generally effective across a range of settings and populations, they could be even more effective when based on the latest research and theory. Thus, apart from specific recommendations, we hope to show the benefits of an integrated evidence‐based approach to the application of token reinforcement principles in educational and clinical settings. [ABSTRACT FROM AUTHOR]

Pigeon and human subjects were given repeated choices between variable and adjusting delays to token reinforcement that titrated in relation to a subject's recent choice patterns. Indifference curves were generated under two different procedures: "immediate exchange," in which a token earned during each trial was exchanged immediately for access to the terminal reinforcer (food for pigeons, video clips for humans), and "delayed exchange," in which tokens accumulated and were exchanged after 11 trials. The former was designed as an analogue of procedures typically used with nonhuman subjects, the latter as an analogue to procedures typically used with human participants. Under both procedure types, different variable-delay schedules were manipulated systematically across conditions in ways that altered the reinforcer immediacy of the risky option. Under immediate-exchange conditions, both humans and pigeons consistently preferred the variable delay, and indifference points were generally ordered in relation to relative reinforcer immediacies. Such risk sensitivity was greatly reduced under delayed-exchange conditions. Choice and trial-initiation response latencies varied directly with indifference points, suggesting that local analyses may provide useful ancillary measures of reinforcer value. On the whole, the results indicate that modifying procedural features brings choices of pigeons and humans into better accord, and that human-nonhuman differences on risky choice procedures reported in the literature may be at least partly a product of procedural differences. (Contains 13 figures and 2 tables.)

Token reinforcement procedures and concepts are reviewed and discussed in relation to general principles of behavior. The paper is divided into four main parts. Part I reviews and discusses previous research on token systems in relation to common behavioral functions--reinforcement, temporal organization, antecedent stimulus functions, and aversive control--emphasizing both the continuities with other contingencies and the distinctive features of token systems. Part II describes the role of token procedures in the symmetrical law of effect, the view that reinforcers (gains) and punishers (losses) can be measured in conceptually analogous terms. Part III considers the utility of token reinforcement procedures in cross-species analysis of behavior more generally, showing how token procedures can be used to bridge the methodological gulf separating research with humans from that with other animals. Part IV discusses the relevance of token systems to the field of behavioral economics. Token systems have the potential to significantly advance research and theory in behavioral economics, permitting both a more refined analysis of the costs and benefits underlying standard economic models, and a common currency more akin to human monetary systems. Some implications for applied research and for broader theoretical integration across disciplines will also be considered. (Contains 10 figures.)

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. (Contains 8 figures and 1 table.)

Two experiments were conducted to compare choices between sequences of reinforcers in pigeon (Experiment 1) and human (Experiment 2) subjects, using functionally analogous procedures. The subjects made pairwise choices among 3 sequence types, all of which provided the same overall reinforcement rate, but differed in their temporal patterning. Token reinforcement schedules were used in both experiments and the type of exchange schedule varied across blocks of sessions. Some conditions permitted immediate exchange of tokens for consumable reinforcers (food for pigeons, video access for humans); in other conditions, tokens accumulated and were exchanged for consumable reinforcers only at the end of the sequence. Choice patterns in the immediate-exchange conditions were generally similar across species, with both pigeons and humans preferring sequences with the shortest delay to the initial reinforcer in the series. The results are broadly consistent with models of temporal discounting expanded to include the impact of sequences of delayed reinforcers acting in parallel from the time of the choice. Preferences were less consistent with discounting models in the delayed exchange conditions. Questionnaire data gathered at the end of the experiment were consistent with prior results of questionnaire studies, but showed no straightforward relation to the observed choice patterns, urging caution in the extrapolation of results from one decision-making domain to the other. (Contains 2 tables and 8 figures.)

The sunk cost effect occurs when an individual persists following an initial investment, even when persisting is costly in the long run. The current study used a laboratory model of the sunk cost effect. Two response alternatives were available: Pigeons could persist by responding on a schedule key with mixed ratio requirements, or escape by responding on a second key. In Experiment 1, mean response requirements for persistence and escape were varied across conditions. Pigeons persisted (committing the sunk cost error) when persisting increased the mean response requirement only slightly but not when persisting was sufficiently nonoptimal. Experiment 2 explored more systematically combinations of ratios and probabilities assigned to the schedule key. Persistence varied with the ratio of the mean global response requirements for persistence and escape. In Experiment 3, transitions between ratios were signaled. This reduced nonoptimal persistence, and produced some instances of a reverse sunk cost error--escaping when persistence was optimal. In Experiment 4, it was optimal to escape after the second-smallest ratio ever presented. Pigeons escaped at approximately the optimal juncture, especially in conditions with added signals. Overall, this series of experiments suggests that the sunk cost error may arise in part because persistence is the default behavioral strategy in situations where the contingencies for escape and persistence are insufficiently disparate and/or it is relatively difficult to discriminate when to escape. The study also demonstrates the utility of animal models of complex decision making situations. (Contains 6 tables and 6 figures.)

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. (Contains 1 table and 5 figures.)

Pigeons pecked a response key on a variable-interval (VI) schedule, in which responses produced food every 40 s, on average. These VI periods, or components, alternated in irregular fashion with extinction components in which food was unavailable. Pecks on a second (observing) key briefly produced exteroceptive stimuli (houselight flashes) correlated with the component schedule currently in effect. Across conditions within a phase, the dependency between observing and presentation of the stimuli was decreased systematically while the density of stimulus presentation was held constant. Across phases, the proportion of session time spent in the VI component was adjusted from 0.5 to 0.25, and then to 0.75. Results indicate that rate of observing decreased as the dependency between responses and stimulus presentations was decreased. Further, discriminative control by the schedule-correlated stimuli was systematically weakened as dependency was decreased. Increasing the proportion of session time spent in VI decreased the rate of observing. This effect was additive with the manipulation of the dependency between observing and presentation of the stimuli. Overall, these results show that conditioned reinforcers function similarly to unconditioned reinforcers with respect to response-consequence dependencies, and that stimulus control is enhanced under conditions in which the relevant stimuli are produced by an organism's behavior. (Contains 3 figures and 2 tables.)

Two experiments with pigeons investigated the effects of contingencies between interresponse times (IRTs) and the transitions between the components of 2- and 4-component chained schedules (Experiments 1 and 2, respectively). The probability of component transitions varied directly with the most recent (Lag 0) IRT in some experimental conditions and with the 4th (Lag 4) IRT preceding the most recent one in others. Mean component durations were constant across conditions, so the reinforcing effect of stimulus change was dissociated from that of delay to food. IRTs were longer in the Lag-0 than in the Lag-4 conditions of both experiments, thus demonstrating that stimulus change functioned as a reinforcer. In the Lag-0 conditions of Experiment 2, the Component-1 IRTs increased more than the Component-2 IRTs, which in turn increased more than the Component-3 IRTs. This finding runs counter to the conditioned-positive-reinforcement account of chained-schedule responding, which holds that the reinforcing effect of stimulus change should vary in strength as an inverse function of the delay to the unconditioned reinforcer at the end of the chain because conditioned reinforcement is due to first- or higher- order classical conditioning. Therefore, we present other possible explanations for this effect. (Contains 6 figures and 2 tables.)

Two experiments examined pigeons' postponement of a signaled extinction period, or timeout (TO), from an ongoing schedule of response-dependent food delivery. A concurrent-operant procedure was used in which responses on one (food) key produced food according to a variable-interval schedule and responses on a second (postponement) key delayed the next scheduled TO according to a response-TO (R-TO) interval. A series of response-independent stimulus changes on the food key temporally partitioned the R-TO into three equal segments (S1, S2, and S3). Postponement responses, in addition to postponing TO, also reinstated S1, the stimulus correlated with the greatest temporal distance from TO. In Experiment 1, the R-TO interval was manipulated systematically across blocks of sessions (conditions) at a given ratio of R-TO:TO duration. This R-TO:TO ratio was manipulated across blocks of conditions (phases). Postponement response rates varied inversely with R-TO interval in each phase. Changes in the R-TO:TO ratio did not produce consistent differences except at the 1:10 ratio for some pigeons, where it disrupted postponement responding in some conditions. Most of the postponement responses occurred in the presence of S2 and S3, the stimuli most proximal to TO, whereas most of the food-key responses occurred in S1. In Experiment 2, the R-TO contingencies were systematically manipulated in the presence of the time-correlated stimuli. In one set of conditions, the R-TO contingencies were made either ineffective or less effective in the presence of one or more stimuli. Postponement responses typically shifted to stimuli in the presence of which responses were relatively more effective. Postponement responses decreased markedly when the added stimuli were removed, and then recovered when the stimuli were reinstated. Results from both experiments indicate that the added stimuli in a discriminated TO-avoidance procedure serve predominately discriminative functions, delineating periods during which behavior is maximally effective. The results parallel those obtained in shock-avoidance procedures, providing further evidence that TO functions as an aversive stimulus. (Contains 2 tables and 6 figures.)

Four pigeons were exposed to second-order schedules of token reinforcement, with stimulus lights serving as token reinforcers. Tokens were earned according to a fixed-ratio (token-production) schedule, with the opportunity to exchange tokens for food (exchange period) occurring after a fixed number had been produced (exchange-production ratio). The token-production and exchange-production ratios were manipulated systematically across conditions. Response rates varied inversely with the token production ratio at each exchange-production ratio. Response rates also varied inversely with the exchange-production ratio at each token-production ratio, particularly at the higher token-production ratios. At higher token-production and exchange-production ratios, response rates increased in token-production segments closer to exchange periods and food. Some conditions were conducted in a closed economy, in which the pigeons earned all their daily ration of food within the session. Relative to comparable open-economy conditions, response rates in the closed economy were less affected by changes in token-production ratio, resulting in higher levels of food intake and body weight. Some of the results are consistent with the economic concept of unit price, a cost-benefit ratio comprised of responses per unit of food delivery, but most are well accounted for by a consideration of the number of responses required to produce exchange periods, without regard to the amount of reinforcement available during those exchange periods. (Contains 1 table and 5 figures.)

Pigeons were exposed to multiple and concurrent second-order schedules of token reinforcement, with stimulus lights serving as token reinforcers. Tokens were produced and exchanged for food according to various fixed-ratio schedules, yielding equal and unequal unit prices (responses per unit food delivery). On one schedule (termed the "standard schedule"), the unit price was held constant across conditions. On a second schedule (the "alternative schedule"), the unit price was either the same or different from the standard. Under conditions with unequal unit prices, near-exclusive preference for the lower unit price was obtained. Under conditions with equal unit prices, the direction and degree of preference depended on ratio size (number of responses per exchange period). When this ratio differed, strong preferences for the smaller ratio were observed. When this ratio was equal, preferences were nearer indifference. Response rates on the multiple schedule were generally consistent with the preference data in showing sensitivity to ratio size. Results are discussed in terms of a unit-price model that includes handling and reinforcer immediacy as additional costs. On the whole, results show that preferences were determined primarily by delay to the exchange period. (Contains 2 tables and 9 figures.)

The present study was designed to help bridge the methodological gap between human and nonhuman animal research in delay-based risky choice. In Part 1, 4 adult human subjects made repeated choices between variable-time and fixed-time schedules of 30-s video clips. Both alternatives had equal mean delays of 15 s, 30 s, or 60 s. Three of 4 subjects strongly preferred the variable-delay alternative across all conditions. In Part 2, these 3 subjects were then provided pairwise choices between 2 variable-time schedules with different delay distributions. Subjects generally preferred the variable-delay distributions with a higher probability of short-reinforcer delays, consistent with accounts based on nonlinear discounting of delayed reinforcement. There was only weak correspondence between experimental results and verbal reports. The overall pattern of results is inconsistent with prior risky choice research with human subjects but is consistent with prior results with nonhuman subjects, suggesting that procedural differences may be a critical factor determining risk-sensitivity across species. Keywords: risky choice, distributional characteristics, delay sensitivity, video reinforcement, adult humans

Three adult humans were presented with choices between fixed and variable (probabilistic) numbers of points exchangeable for money. The mean number of points per trial was held constant across fixed and variable outcomes while the form of the distribution of outcomes on the variable option was manipulated. Across conditions, choice was assessed across bivalued, rectangular, reverse exponential, and approximately normal probability distributions. To more closely approximate procedures used with nonhumans, contingencies were experienced directly across repeated trials under steady-state conditions, and potential verbal influences were minimized. Subjects strongly preferred the fixed option across most conditions regardless of distribution type. The results replicate and extend those obtained with humans' choices involving verbal/hypothetical outcomes and with nonhumans' choices involving food reinforcers, and they illustrate a potentially useful procedure for cross-species comparisons in risky choice., A number of experiments have investigated how the form of a probability distribution affects risk sensitivity (e.g., Bernstein, Chapman, Christensen, & Elstein, 1997; Coombs & Bowen, 1971; Coombs & Lehner, [...]

Risk-taking behavior research about energy-budget variables demonstrates patterns correlating to choices that do not involve immediate survival concerns. When studied under similar experimental conditions, risky choice in humans appears similar to that shown by non-humans.

Reinforcement experiments on pigeons suggest behavior is negatively reinforced by timeout postponement. A discrete-trial series of experiments were designed that neither decreased timeout frequency nor increased food enforcement.

A behavioral analysis of human information processing is presented, focusing on the relationship between reinforcement rates and response rates. An analysis of the patterns of panel pressing by adults in exchange for money is detailed.

Four experiments show that self control in pigeons depends more on the delay to the period of exchange between light-emitting diodes and food than on delay to token presentation. Self control under different token reinforcer situations may differ with the discriminative properties of tokens. Use of token versus food reinforcers with humans versus pigeons, respectively, may be responsible for the differences in their self control choices.

An experiment on humans' choices in situations of time-based diminishing returns examined the effects of fixed-interval (FI) duration and progressive-interval (PI) step size. Results showed switching from PI to FI was more frequent and earlier in the PI progression in reset conditions than in no-reset conditions. Switching was systematically linked to FI duration in both reset and no-reset conditions for every PI step size, demonstrating sensitivity to FI size. Finally, the development of organized choice patterns did not depend on schedule-controlled response patterns or verbal descriptions of the contingencies.

An experiment with four subjects to compare instructional and schedule influences on human behavior shows that subjects follow instructions as long as they are appropriate and even after they have deviated from the optimum, but ultimately switch to situation guided behavior. The experiment consisted of many 15-minute sessions in which the subject had to analyze the sequence of choices between a fixed- and a progressive-time schedule to select the one that would fetch the maximum points. The standard instructions provided were initially optimal but gradually became less appropriate as the size of the progressive step was changed. The step size was first increased gradually and later decreased.

The distinction between organism-based and environment-based theories of behaviorism is valid, despite J.E.R. Staddon's belief that it is arbitrary. Environment-based explanations are necessarily historical, despite Staddon's view to the contrary, while from the organism-based view, the concepts of environment-based theory may not appear theoretical.

Horne and Lowe's paper provides a remarkable behavioral-analytic theoretical framework for the study of naming that draws not only from the field of behavior analysis but also from other areas. Their theoretical re-conceptualization is a plausible account of the development and maintenance of naming, and how it might be connected to other verbal behaviors. A problem with this scientific interpretation, however, is that it results in confusion between causes and effects. There is no clear distinction between characteristics needed to produce an outcome and characteristics that are only incidental to the outcome.