Reinforcement magnitude and pausing on progressive-ratio schedules

Rats responded under progressive-ratio schedules for sweetened milk reinforcers; each session ended when responding ceased for 10 min. Experiment 1 varied the concentration of milk and the duration of postreinforcement timeouts. Postreinforcement pausing increased as a positively accelerated function of the size of the ratio, and the rate of increase was reduced as a function of concentration and by timeouts of 10 s or longer. Experiment 2 varied reinforcement magnitude within sessions (number of dipper operations per reinforcer) in conjunction with stimuli correlated with the upcoming magnitude. In the absence of discriminative stimuli, pausing was longer following a large reinforcer than following a small one. Pauses were reduced by a stimulus signaling a large upcoming reinforcer, particularly at the highest ratios, and the animals tended to quit responding when the past reinforcer was large and the stimulus signaled that the next one would be small. Results of both experiments revealed parallels between responding under progressive-ratio schedules and other schedules containing ratio contingencies. Relationships between pausing and magnitude suggest that ratio pausing is under the joint control of inhibitory properties of the past reinforcer and excitatory properties of stimuli correlated with the upcoming reinforcer, rather than under the exclusive control of either factor alone.     

Good to the last drop? Millikan stories as “canned” pedagogy

In recent literature, the famous Millikan oil-drop experiment appears as a case of “good scientific judgment” on the one hand, and scientific misconduct on the other. This article discusses different interpretations of the fact that Nobel laureate Robert Millikan’s notebooks show that he eliminated a number of oildrops in his published 1913 paper on the charge of the electron, while reporting that he had included all the drops. Starting with the common source of all Millikan stories, historian of physics Gerald Holton’s 1978 paper, I discuss recent “canned” versions of Millikan-as-misbehaver in books on scientific fraud. Then I examine some versions of Millikan-as-good-scientist, particularly the reconstruction by historian of physics Allan Franklin, and the views of some practicing physicists. Finally, we have an instructive head-on collision between the two standard treatments of Millikan. The problem with canned stories is not only insufficient information; we also lack a realistic evaluation of the role of ethics in science. As a fundamentally knowledge-seeking enterprise, science may harbor an inherent, perhaps irresolvable, conflict between scientific and ethical concerns. The author’s special interests include standards for “good science”, science and values, and social psychology.     

初中学业不良学生习得性无能研究

采用两个２×２实验设计,研究强化方式、成就状况和任务类型对初中学业不良学生习得性无能倾向的影响二结果表明：外部奖赏不能提高成功组学生的内在动机,反而增加挫折组学生的无力感与挫折感;操作作业的成败对学生习得性无能倾向影响不明显,而数学作业的成败的影响则非常显著;学生在操作作业中的内在动机明显高于其在数学作业中的内在动机。     

Independence of reinforcement delay and magnitude in concurrent chains

A three-component concurrent-chains procedure was used to investigate preference between terminal-link schedules that differed in delay and magnitude of reinforcement. Response and time allocation data were well described by a generalized matching model. Sensitivity to delay appeared to be lower when reinforcement magnitudes were unequal than when they were equal, but when obtained rather than programmed time spent responding in the initial links was used in the model, the difference vanished. The results support independence of delay and magnitude as separate dimensions of reinforcement value, as required by the matching law, and the assumption of the contextual choice model (Grace, 1994) that sensitivities to delay and magnitude are affected similarly by temporal context. Although there was statistical evidence for interaction between successive components, the effects were small and transient. The multiple-component concurrent-chains procedure should prove useful in future research on multidimensional preference, although it may be necessary to control obtained initial-link time more precisely.     

The effects of smoked marijuana on progressive-interval schedule performance in humans.

In three experiments, 8 human subjects participated in a study of the effects of smoked marijuana on progressive-interval schedule performance. A two-component chained progressive-interval fixed-interval schedule of point delivery was used. In the progressive-interval component, the interval length began at 20 s and increased either geometrically or arithmetically (by either 20 s, 40 s, 80 s, 100 s, or 160 s) on each subsequent interval. After this interval elapsed, a single button press produced the fixed-interval component, with a total of five reinforcers of varying magnitude ($0.05, $0.20, or $0.40) available on a fixed-interval 20-s schedule. After the five reinforcer deliveries, the schedule returned to the initial progressive-interval component. Several relationships were found among rates of responding, postreinforcement pauses and drug administration in the progressive-interval component: (a) Postreinforcement pauses increased as the temporal requirements of the progressive-interval schedule increased; (b) rates of responding during successive progressive-interval components rapidly decreased to low rates of responding after the first few progressions; (c) postreinforcement pauses decreased systematically as dose of smoked marijuana increased; and (d) rates of responding increased after smoking active marijuana but not after smoking placebo cigarettes. Results are discussed in the context of behavioral control and relevance to other studies that have investigated the effects of smoked marijuana on schedule performance.     

Zebrafish choice behavior is sensitive to reinforcer rate,immediacy, and magnitude ratios

Behavioral flexibility has, in part, been defined by choice behavior changing as a function of changes in reinforcer payoffs. We examined whether the generalized matching law quantitatively described changes in choice behavior in zebrafish when relative reinforcer rates, delays/immediacy, and magnitudes changed between two alternatives across conditions. Choice was sensitive to each of the three reinforcer properties. Sensitivity estimates to changes in relative reinforcer rates were greater when 2 variable-interval schedules were arranged independently between alternatives (Experiment 1a) than when a single schedule pseudorandomly arranged reinforcers between alternatives (Experiment 1b). Sensitivity estimates for changes in relative reinforcer immediacy (Experiment 2) and magnitude (Experiment 3) were similar but lower than estimates for reinforcer rates. These differences in sensitivity estimates are consistent with studies examining other species, suggesting flexibility in zebrafish choice behavior in the face of changes in payoff as described by the generalized matching law.     

视频游戏对认知能力的影响及其神经基础

视频游戏是一类需要借助视听设备并基于一定剧情进行操作的游戏。先前研究大多关注暴力视频游戏对攻击等负面行为的影响,但本文着重探讨视频游戏对个体认知能力的积极影响及内在神经基础,以辩证看待视频游戏对个体心理和行为的作用。本文对前人研究归纳梳理发现,视频游戏训练能使个体认知能力得到持久改善,同时论述了视频游戏中脑神经基础和奖赏预期对认知能力的调控作用。未来研究应在规范视频游戏训练技术的基础上,用其干预靶脑区以提升个体特定脑功能。     

Dissociation of reward and effort sensitivity in methcathinone‐induced Parkinsonism

Methcathinone‐induced Parkinsonism is a recently described extrapyramidal syndrome characterized by globus pallidus and substantia nigra lesions, which provides a unique model of basal ganglia dysfunction. We assessed motivated behaviour in this condition using a novel cost‐benefit decision‐making task, in which participants decided whether it was worth investing effort for reward. Patients showed a dissociation between reward and effort sensitivity, such that pallidonigral complex dysfunction caused them to become less sensitive to rewards, while normal sensitivity to effort costs was maintained.     

A Measure of Delay Discounting Within the Academic Domain

It is important to better understand the decision‐making processes involved in student procrastination, in order to develop interventions that reduce this common problem. Students may procrastinate because studying produces delayed reinforcers; however, no task measuring delay discounting of academic outcomes currently exists. In Experiment 1, we developed and piloted a measure of academic discounting modeled on titrating‐amount tasks successfully used in the discounting literature. Participants made hypothetical choices between working for money (the smaller, sooner reinforcer) and working on an assignment that was due at various times (the larger, later reinforcer). Participants showed systematic decreases in the subjective value of the assignment as a function of delay, and the hyperbolic and hyperboloid models described the shape of this decrease in value well. In general, larger delayed rewards are discounted less steeply than smaller delayed rewards (the magnitude effect). In Experiment 2, we observed the magnitude effect in academic discounting: Participants discounted a “not important” assignment more steeply than an “important” assignment. In the hyperboloid model, this change was captured by an increase in the s parameter. Results provide support for the validity of the academic discounting task. Copyright © 2018 John Wiley & Sons, Ltd.     

奖赏结构与结果效价对男女儿童成就归因的影响

本研究的目的是考察奖赏结构和结果效价对男女儿童归因风格的影响.被试为小学五年级学生(n=74,男生36人,女生38人),实验通过解决一系列迷津测验来创设成功和失败情境.研究结果表明,能力、运气归因存在性别差异,在竞争奖赏结构条件下,女生对成就状况倾向于做运气归因,而男生倾向于做运气以外其他因素的归因(如能力);在非竞争奖赏结构条件下,男生对成就状况倾向于做运气归因,而女生倾向于做运气以外其他因素的归因.此外,还发现了一些其他的显著效应.