Choice patterns reveal qualitative individual differences among discounting of delayed gains,delayed losses,and probabilistic losses

A new probabilistic losses questionnaire as well as Kirby's delayed gains questionnaire and a previously developed delayed losses questionnaire were administered to a large online sample. Almost all participants showed the positive discounting choice pattern expected on the Kirby questionnaire, decreasing their choice of a delayed gain as time to its receipt increased. In contrast, approximately 15% of the participants showed negative discounting on the delayed losses questionnaire and/or the probabilistic losses questionnaire, decreasing their choice of an immediate loss as time to a delayed loss decreased and/or decreasing their choice of a certain loss as likelihood of the probabilistic loss increased. Mixture model analysis confirmed the existence of these negative discounting subgroups. The inconsistent findings observed in previous research involving delayed/probabilistic losses may be due to differences in the proportion of negative discounters who participated in previous studies. Further research is needed to determine how negative discounting of delayed and probabilistic losses manifests itself in everyday decisions. It should be noted that the presence of individuals who show atypical choice patterns when losses are involved may pose challenges for efforts to modify discounting in order to ameliorate behavioral problems, especially because many such problems concern choices that have negative consequences, often delayed and/or probabilistic.     

Social discounting of pain

Impatience can be formalized as a delay discount rate, describing how the subjective value of reward decreases as it is delayed. By analogy, selfishness can be formalized as a social discount rate, representing how the subjective value of rewarding another person decreases with increasing social distance. Delay and social discount rates for reward are correlated across individuals. However no previous work has examined whether this relationship also holds for aversive outcomes. Neither has previous work described a functional form for social discounting of pain in humans. This is a pertinent question, since preferences over aversive outcomes formally diverge from those for reward. We addressed this issue in an experiment in which healthy adult participants (N = 67) chose the timing and intensity of hypothetical pain for themselves and others. In keeping with previous studies, participants showed a strong preference for immediate over delayed pain. Participants showed greater concern for pain in close others than for their own pain, though this hyperaltruism was steeply discounted with increasing social distance. Impatience for pain and social discounting of pain were weakly correlated across individuals. Our results extend a link between impatience and selfishness to the aversive domain.     

Magnitude effect contributes to the domain specificity in delay discounting

Discounting is a useful framework for understanding temporal choices. A person who prefers $50 immediately over $100 in 1 month exhibits a higher discount rate than a person deciding to wait for the higher payoff. Although previous research shows that discount rates are domain-specific, we propose an alternative to the domain specificity account. We suggest that differences in discounting alternatives across various domains may result not so much from the domains' nature per se but from differences in perceived attractiveness of the discounted alternatives. We replicated that an illustrative study evidencing domain specificity in discounting (Experiment 1) showed that people's subjective values of the payoffs in domains discounted in this experiment were different (Experiment 2) and used a novel method to match the attractiveness of the available alternatives across domains (Experiment 3). Finally, Experiment 4 showed that when matching was applied, the domain effect disappeared. We conclude that a magnitude effect can, at least partially, explain domain specificity in delay discounting.     

Heterogeneous load balancing clustering protocol for Wireless Sensor Networks

Wireless Sensor Networks is one of the most significant area of research where large number of sensor nodes that are distributed in a geographical area operate on limited battery power. As these networks, depending on the application, are sometimes deployed in in-hostile environment, which makes energy conservation one of the major challenge faced in WSN. To reduce energy consumption, clustering is considered to be the most efficient technique. This work proposes a new clustering approach that decreases energy consumption and results in prolonged network lifetime which is an important requirement for networks operating in inaccessible areas. In the proposed approach, heterogeneity is also implemented to increase the stability and energy efficiency of random networks. We have evaluated the efficiency of the proposed protocol through simulations and comparison is performed with well-known existing distributed protocols. Proposed approach shows efficient results in terms of the stability period for different network configurations and Base Station positions. Also, the results are found better in terms of number of alive nodes and network lifetime.     

物质成瘾领域延迟折扣研究中的外部效度问题

物质成瘾者的跨期决策缺陷已被大量使用金钱延迟折扣任务的研究所证实。然而近年来, 来自金钱延迟折扣任务变式(成瘾物质延迟折扣任务、性延迟折扣任务和跨类别延迟折扣任务)的发现表明, 在物质成瘾领域的延迟折扣研究中单一使用金钱延迟折扣任务存在一定的局限性。首先, 物质成瘾者对金钱的延迟折扣水平可能并不能完全代表其对成瘾物质、性和其它自然奖赏的延迟折扣水平; 其次, 仅使用单一延迟折扣任务可能存在对物质成瘾者跨期决策过程的过度简化; 最后, 金钱延迟折扣任务较其变式对物质成瘾者的一些临床特征不够敏感。未来研究应进一步丰富、拓展物质成瘾领域的跨类别延迟折扣研究, 并对可能影响跨期决策的时间因素进行深入探索。     

How Category Selection Impacts Inference Reliability: Inheritance Inference From an Ecological Perspective

This article presents results from a simulation-based study of inheritance inference, that is, inference from the typicality of a property among a “base” class to its typicality among a subclass of the class. The study aims to ascertain which kinds of inheritance inferences are reliable, with attention to the dependence of their reliability upon the type of environment in which inferences are made. For example, the study addresses whether inheritance inference is reliable in the case of “exceptional subclasses” (i.e., subclasses that are known to be atypical in some respect) and attends to variations in reliability that result from variations in the entropy level of the environment. A further goal of the study is to show that the reliability of inheritance inference depends crucially on which sorts of base classes are used in making inferences. One approach to inheritance inference treats the extension of any atomic predicate as a suitable base class. A second approach identifies suitable base classes with the cells of a partition (of a preselected size k) of the domain of objects that satisfies the condition of maximizing the similarity of objects that are assigned to the same class. In addition to permitting more inferences, our study shows that the second approach results in inheritance inferences that are far more reliable, particularly in the case of exceptional subclasses.     

人们如何设想未来：未来情景思维对个体心理和行为的影响

未来情景思维(Episodic Future Thinking, EFT)主要指人们基于当前情景或过去经历来思考、想象未来的过程, 是人们对于未来的一种设想。根据已有的行为实验和神经影像学等多个方面的研究结果, 系统论述了未来情景思维的概念和特征, 以及个体过去的生活经历及相应记忆和个体生活目标对其的影响, 通过概括和分析行为和脑神经两方面的证据来论述未来情景思维会对人们具体生活实践产生积极与消极的双向影响。当然, 未来还需要进一步加强未来情景思维研究的广度和深度, 特别是要细化未来情景思维的类型, 探讨未来情景思维可能导致的不适应行为以及影响个体心理和行为的作用机制, 从而为人们如何更积极地适应未来提供更充分的实证证据和理论构想。     

任务框架及利他人格对社会折扣的影响

与自我存在一定社会距离的他人获得收益或遭受损失都会给自我带来一定的效用,这种效用随着与他人间社会距离的增加而减少,该现象被称为社会折扣。本研究采用情境式选择滴定程序,探索并比较了“为他人得益而放弃自我得益”(NG-G)、“为他人不失而放弃自我得益”(NG-NL)、“为他人得益而承担自我损失”(L-G)以及“为他人不失而承担自我损失”(L-NL)4种任务框架下的社会折扣程度。结果发现：(1)4种框架下,指数模型均比双曲模型更好地描绘了被试的社会折扣规律;(2)任务框架影响社会折扣程度,“为他人不失”框架下(含NG-NL、L-NL)的折扣程度比“为他人得益”框架下(含NG-G、L-G)低;(3)任务框架与社会距离的交互作用影响社会折扣程度。随着社会距离增加, NG-G与NG-NL框架下折扣程度的差异逐渐变小, L-G与L-NL框架下折扣程度的差异也逐渐变小;(4)社会距离与利他人格的交互作用显著,高低利他人格者的社会折扣程度只在社会距离较远时存在显著差异。上述结果表明,个体不仅存在自我损失规避倾向,也存在不同程度的他人损失规避倾向。     

Smokers discount their drug of abuse in the same way as other consumable rewards

Recent research shows that drug abusers discount delayed monetary rewards more than nonabusers do, and they discount delayed substances of abuse (e.g., drugs) more than delayed money. Furthermore, non-drug-abusers discount food and substances of abuse (e.g., alcohol), more than money. Here, we compare the delay and probability discounting of money with that of a directly consumable reward (chocolate) and with that of a substance of abuse (cigarettes), in a drug-using population (smokers). In line with previous research, we found in two experiments that delay discounting differentiated between smokers and nonsmokers, and between money and a nonabused directly consumable reward (chocolate). In addition, our results show that there appears to be no difference in the extent to which smokers discount their abused substance compared to another directly consumable reward. These findings support the contention that drugs and food are part of the same category of primary reinforcers, whereas money is discounted differently, as a conditioned reinforcer.