PREFERENCE REVERSALS DUE TO MYOPIC DISCOUNTING OF DELAYED REWARD

Abstract— A basic stationarity axiom of economic theory assumes stable preference between two deferred goods separated by a fixed time. To test this assumption, we offered subjects choices between delayed rewards, while manipulating the delays to those rewards. Preferences typically reversed with changes in delay, as predicted by hyperbolic discounting models of impulsiveness. Of 36 subjects, 34 reversed preference from a larger, later reward to a smaller, earlier reward as the delays to both rewards decreased. We conclude that the stationarity axiom is not appropriate in models of human choice.     

THE REWARDS AND HAZARDS OF COMPUTER SIMULATIONS

Although computer simulations and other modeling tools have assumed a pivotal role in cognitive psychology, their utility continues to be questioned by some psychologists. This article presents several examples that illustrate both rewards and potential hazards associated with the simulation approach. Simulations can provide the formal framework necessary to disambiguate new ideas, they can explore the implications of complex models, and they can predict seemingly counterintuitive findings or uncover hidden relationships. At the same time, care must be taken to avoid pitfalls that may arise when computer code inadvertently differs from the intended specifications of a theory, or when predictions derive not from fundamental properties of a theory but from pragmatic choices made by the modeler.     

ALTERING THE MAGNITUDE OF DELAY DISCOUNTING BY PATHOLOGICAL GAMBLERS

The present study explored the delay discounting of future and past monetary rewards by pathological gamblers. Using a multiple baseline design, following repeated exposure to choices between smaller immediate and larger delayed consequences, participants completed a relational responding task that attempted to alter the psychological functions of irrelevant stimuli and to affect subsequent delay discounting. Results support previous literature on the discounting of delayed consequences by pathological gamblers, illustrate that the discounting of past rewards occurs in a similar fashion to the well‐documented literature on the discounting of future rewards, and that magnitude of discounting can be altered.     

DELAYED REINFORCEMENT OF OPERANT BEHAVIOR

The experimental analysis of delay of reinforcement is considered from the perspective of three questions that seem basic not only to understanding delay of reinforcement, but, also, by implication, the contributions of temporal relations between events to operant behavior. The first question is whether effects of the temporal relation between responses and reinforcers can be isolated from other features of the environment that often accompany delays, such as stimuli or changes in the temporal distribution or rate of reinforcement. The second question is that of the effects of delays on operant behavior. Beyond the common denominator of a temporal separation between reinforcers and the responses that produce them, delay of reinforcement procedures differ from one another along several dimensions, making delay effects circumstance dependent. The final question is one of interpreting delay of reinforcement effects. It centers on the role of the response—reinforcer temporal relation in the context of other, concurrently operating behavioral processes.     

ISOLATING BEHAVIORAL MECHANISMS OF INTERTEMPORAL CHOICE: NICOTINE EFFECT ON DELAY DISCOUNTING AND AMOUNT SENSITIVITY

Many drugs of abuse produce changes in impulsive choice, that is, choice for a smaller—sooner reinforcer over a larger—later reinforcer. Because the alternatives differ in both delay and amount, it is not clear whether these drug effects are due to the differences in reinforcer delay or amount. To isolate the effects of delay, we used a titrating delay procedure. In phase 1, 9 rats made discrete choices between variable delays (1 or 19 s, equal probability of each) and a delay to a single food pellet. The computer titrated the delay to a single food pellet until the rats were indifferent between the two options. This indifference delay was used as the starting value for the titrating delay for all future sessions. We next evaluated the acute effects of nicotine (subcutaneous 1.0, 0.3, 0.1, and 0.03 mg/kg) on choice. If nicotine increases delay discounting, it should have increased preference for the variable delay. Instead, nicotine had very little effect on choice. In a second phase, the titrated delay alternative produced three food pellets instead of one, which was again produced by the variable delay (1 s or 19 s) alternative. Under this procedure, nicotine increased preference for the one pellet alternative. Nicotine‐induced changes in impulsive choice are therefore likely due to differences in reinforcer amount rather than differences in reinforcer delay. In addition, it may be necessary to include an amount sensitivity parameter in any mathematical model of choice when the alternatives differ in reinforcer amount.     

THE DEVELOPMENT AND GENERALIZATION OF DELAYED IMITATION1

An individual's behavior can be identified as imitative if it temporally follows the behavior of another individual and if its topography is controlled by the demonstrated behavior [Baer, Peterson, and Sherman (Journal of the Experimental Analysis of Behavior, 1967, 10 , 405–416)]. This definition takes into account both temporal and topographical characteristics of the behavior in question. More recent research in the area of imitation has interpreted the temporal component of the above definition differentially by limiting imitation to those topographically similar responses occurring within 3, 5, or 10 sec after a model's demonstration. Yet, Gewirtz and Stingle (Psychological Review, 1968, 75 , 375–397) pointed out that much of the imitation seen in young children is not of this immediate nature, but instead occurs sometime after a model's response. They further suggest that this type of imitative behavior can be characterized as a response class and is susceptible to development and modification as a function of consequences delivered to subjects contingent on this type of delayed responding. Four retarded children, three initially imitative and one nonimitative, were individually trained to imitate a number of motor responses in an immediate and a delayed fashion. Immediate imitation was defined as a response similar to a model's demonstration occurring within 5 sec after the model's demonstration; delayed imitation was defined as a response similar to a model's demonstration occurring more than 5 sec, but not more than 25 sec, after the model's demonstration. A reversal (ABAB) design was employed to examine the experimental development of a generalized delayed imitative repertoire. Untrained probe responses were demonstrated to subjects systematically through the ongoing training. Generalized immediate and delayed imitation were observed in each subject; this generalization was restricted to the type of imitation currently undergoing training. This development of a generalized imitation repertoire was observed in each subject. That is, these subjects imitated some responses that had never been specifically trained. More importantly, a training package consisting of prompting, fading, and consequences for delayed imitation functioned to develop generalized delayed imitation. These data exemplify a special case of generalization that was a function of the most recent training history of immediate or delayed imitation. The reversal design demonstrated that imitations of nontrained models were either delayed or immediate, depending upon which form of imitation was currently receiving training. Therefore, for each form of imitation trained, delayed or immediate, a corresponding response class was demonstrated. These data relate to data reported by Garcia, Baer, and Firestone (Journal of Applied Behavior Analysis, 1971, 4 , 101–112). The association lies in the proposition that there are identifiable boundaries of generalized imitation and that these boundaries are functionally related to previous training histories.     

INCREASING THE SUPPRESSIVE EFFECT OF DELAYED PUNISHERS: A REVIEW OF BASIC AND APPLIED LITERATURE

Although punishment is a common feature in programs designed to suppress inappropriate responding, the delivery of punishment may be delayed for a variety of reasons. When punishment is delayed, the result may be a decrease in response suppression. It is therefore important to identify strategies to increase the effectiveness of delayed punishers. In this paper, basic and applied research on delayed punishment is reviewed. The delay‐of‐punishment gradient is described, and strategies are provided to increase the suppressive effect of delayed punishers. For each strategy identified, a conceptual account is provided describing how the strategy enables a delayed punisher to exert a suppressive effect. Furthermore, this paper suggests additional uninvestigated but potentially effective strategies and identifies problems with current research into delayed punishment. Finally, recommendations regarding future research into delayed punishers are provided. Copyright © 2012 John Wiley & Sons, Ltd.     

小学儿童奖赏公平性的认知发展

采用信息加工研究途径并假设故事情境探索小学儿童对奖赏公平性的社会认知发展,并将儿童的发展与成人作对比。研究结果表明,７,９岁儿童容易将＂均等＂与＂公平＂混淆,还没形成一个稳定的分配模式,而１２岁儿童已能运用＂努力＂、＂成果＂、＂能力＂等规则较为稳定地作出公平奖赏决定或评价,但还没达到对更高层次的社会准则的理解和掌握。儿童这一发展制约于他们的信息加工能力以及获得有关社会价值观的社会化过程。     

THE EFFECTS OF CONTINGENT AND NONCONTINGENT REWARDS ON THE I.Q. SCORES OF CHILDREN OF ABOVE-AVERAGE INTELLIGENCE1

This study investigated the effects of candy reinforcement on I.Q. test scores in first and second graders of above-average intelligence. Thirty-six subjects were randomly assigned to one of three groups and either given candy contingent on correct responses, noncontingently, or not given candy. After measuring all subjects on Form L of the revised Stanford Binet, each subject in the contingent group was given an M & M immediately following each correct answer on Form M, while a yoked-comparison subject received the same number of M & M's before responding to a question and therefore without regard to correctness of answers. It was expected that both types of candy administration would produce higher I.Q. change scores than the no-candy control group, but there were no statistically significant differences among the three treatments. The differences between the first and second test scores were 4.17 (contingent), 4.67 (noncontingent), and 1.00 (no reinforcement). Reasons for this failure to replicate previous findings were discussed.     

兒童延缓抑制动力学底年龄特征

巴甫洛夫始終把条件性皮貭抑制看为积极的神經过程,它不断地調节着兴奋过程,致使有机体的活动能更正确地适应于外界环境。因而,抑制問題的研究不仅具有理論上的意义。而且具有实践上的意义。 如所周知,作为內抑制形式之一的延緩抑制是构成人与动物的一系列行为的基础。例如,对教育工作来說,具有重要意义的是培养儿童的坚靱性,发展善于在某个特定时間內制止自己的活动,或者在需要的时刻准时地进行活动等等的能力。这些正是以延緩抑制的发展为基础的。     

麦角酰胺对于猕猴纯音延缓防御反应的影响

一、在猕猴上建立了纯音比配延缓防御反应。一般能完成9秒的延缓反应。最长可延缓15秒。 二、静脉注射LSD对于纯音比配延缓反应有明显的影响,药物注射后延缓反应正确百分率由原来80%以上的水平降到10%—70%。一般24小时后即恢复正常。 三、本文对LSD引起的猕猴纯音延缓反应障碍与LSD引起的临床症状作了比较讨论。