Variable-interval schedule performance in open and closed economies

The effect of economy type on reinforcer value

This article reviews studies investigating the effect of economy type on reinforcer value. In a closed economy, consumption of the reinforcer depends entirely on the subject's behavior, whereas in an open economy it does not, due, for example, to the provision of free reinforcers after the session. In theory, reinforcers should have higher value in a closed economy than in an open economy. Experimental results relevant to this prediction and methods used to test economy type effects are summarized and discussed here. Studies have tested the effect of economy type on the value of a variety of reinforcers, including food, water, saccharin, various drugs, and video games. Subjects used have varied also and include humans, monkeys, rats, and mice. Whether economy type had an effect on reinforcer value appears to depend on the particular reinforcer studied and on the species used. In general, where there was a difference in reinforcer value across economies, the effect was consistent with the prediction that value should be lower in the open economy. In some studies, however, satiation across economy types may have been responsible for the difference, or at least contributed to it. Potential explanations for the economy type effect, including substitution of future reinforcers for current reinforcers, contingency degradation, anticipatory contrast, and optimal foraging, are discussed.

Behavioral economics and empirical public policy

The application of economics principles to the analysis of behavior has yielded novel insights on value and choice across contexts ranging from laboratory animal research to clinical populations to national trends of global impact. Recent innovations in demand curve methods provide a credible means of quantitatively comparing qualitatively different reinforcers as well as quantifying the choice relations between concurrently available reinforcers. The potential of the behavioral economic approach to inform public policy is illustrated with examples from basic research, pre-clinical behavioral pharmacology, and clinical drug abuse research as well as emerging applications to public transportation and social behavior. Behavioral Economics can serve as a broadly applicable conceptual, methodological, and analytical framework for the development and evaluation of empirical public policy.

Effects of economy type and nicotine on the essential value of food in rats

The exponential demand equation proposed by Hursh and Silberberg (2008) provides an estimate of the essential value of a good as a function of price. The model predicts that essential value should remain constant across changes in the magnitude of a reinforcer, but may change as a function of motivational operations. In Experiment 1, rats' demand for food across a sequence of fixed-ratio schedules was assessed during open and closed economy conditions and across one- and two-pellet per reinforcer delivery conditions. The exponential equation was fitted to the relation between fixed-ratio size and the logarithm of the absolute number of reinforcers. Estimates of the rate of change in elasticity of food, the proposed measure of essential value, were compared across conditions. Essential value was equivalent across magnitudes during the closed economy, but showed a slight decrease across magnitudes during the open economy. Experiment 2 explored the behavioral mechanisms of nicotine's effects on consumption with the results from Experiment 1 serving as a within-subject frame of reference. The same subjects were administered nicotine via subcutaneously implanted osmotic minipumps at a dose of 3 mg/kg/day and exposed to both the one- and two-pellet conditions under a closed economy. Although nicotine produced large decreases in demand, essential value was not significantly changed. The data from the present experiments provide further evidence for the adequacy of the exponential demand equation as a tool for quantifying the rate of change in elasticity of a good and for assessing behavioral mechanisms of drug action.

A simple BASIC program to generate values for variable-interval schedules of reinforcement

A BASIC program to generate values for variable-interval (VI) schedules of reinforcement is presented. A VI schedule should provide access to reinforcement with a constant probability over a time horizon. If the values in a VI schedule are calculated from an arithmetic progression, the probability of reinforcement is positively correlated with the time since the last reinforcer was delivered. Fleshler and Hoffman (1962) developed an iterative equation to calculate VI schedule values so that the probability of reinforcement remains constant. This easy-to-use program generates VI schedule values according to the Fleshler and Hoffman equation, randomizes the values, and saves the values in ASCII to a disk file.

Second-order schedules of token reinforcement with pigeons: implications for unit price

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.

Does satiation close the open economy?

Pigeons responded on fixed-interval and fixed-ratio food schedules during sessions of extended duration. Pause lengths from the beginning of the session, when the subjects were hungry, resembled those found in open economies, whereas pause lengths from the end of the sessions, when the subjects were close to satiation, resembled those from closed economies. A model of motivation captured key features of the data, suggesting that a changing level of hunger is a causal factor in the behavioral differences observed between open and closed economies. Behavioral theories may provide a parsimonious alternative to economic theories in accounting for such effects.

A preliminary analysis of adaptive responding under open and closed economies

In the current investigation, we evaluated the effects of open and closed economies on the adaptive behavior of 2 individuals with developmental disabilities. Across both types of economy, progressive-ratio (PR) schedules were used in which the number of responses required to obtain reinforcement increased as the session progressed. In closed-economy sessions, participants were able to obtain reinforcement only through interaction with the PR schedule requirements (i.e., more work resulted in more reinforcer access). In open-economy sessions, participants obtained reinforcers by responding on the PR schedule and were given supplemental (free) access to the reinforcers after completion of the session. In general, more responding was associated with the closed economy.