降低决策冲动性的方法及其神经机制

大量实验研究显示, 成瘾患者、多动症患者和病态赌博者在决策中表现出冲动偏好。目前研究冲动性决策偏好的经典实验范式是延迟折扣任务。通过延迟折扣任务, 心理学家揭示了冲动性决策偏好的神经机制并构建了多种理论, 包括单一系统评价理论、双系统评价理论、自我控制理论和自我参照加工理论。基于这些理论, 已经发展出了多种降低决策冲动性的方法, 包括想象未来具体事件、工作记忆训练、预先承诺以及提高血液中葡萄糖水平, 其背后的神经机制是通过认知控制和价值表征理论来实现的。未来研究方向需集中于价值计算、价值系统和多体素模式分析(MVPA)在改善决策冲动性以及内在机制研究上的应用。     

Short-term gains, long-term pains: How cues about state aid learning in dynamic environments

Successful investors seeking returns, animals foraging for food, and pilots controlling aircraft all must take into account how their current decisions will impact their future standing. One challenge facing decision makers is that options that appear attractive in the short-term may not turn out best in the long run. In this paper, we explore human learning in a dynamic decision making task which places short- and long-term rewards in conflict. Our goal in these studies was to evaluate how people’s mental representation of a task affects their ability to discover an optimal decision strategy. We find that perceptual cues that readily align with the underlying state of the task environment help people overcome the impulsive appeal of short-term rewards. Our experimental manipulations, predictions, and analyses are motivated by current work in reinforcement learning which details how learners value delayed outcomes in sequential tasks and the importance that “state” identification plays in effective learning.     

Delay, Probability, and Social Discounting in A Public Goods Game

A human social discount function measures the value to a person of a reward to another person at a given social distance. Just as delay discounting is a hyperbolic function of delay, and probability discounting is a hyperbolic function of odds-against, social discounting is a hyperbolic function of social distance. Experiment 1 obtained individual social, delay, and probability discount functions for a hypothetical $75 reward; participants also indicated how much of an initial $100 endowment they would contribute to a common investment in a public good. Steepness of discounting correlated, across participants, among all three discount dimensions. However, only social and probability discounting were correlated with the public-good contribution; high public-good contributors were more altruistic and also less risk averse than low contributors. Experiment 2 obtained social discount functions with hypothetical $75 rewards and delay discount functions with hypothetical $1,000 rewards, as well as public-good contributions. The results replicated those of Experiment 1; steepness of the two forms of discounting correlated with each other across participants but only social discounting correlated with the public-good contribution. Most participants in Experiment 2 predicted that the average contribution would be lower than their own contribution.     

海洛因延迟强化物超快速折扣倾向的心理机制

以124名处于不同戒除时相的男性海洛因戒除者为被试, 采用金钱和海洛因延迟折扣任务(DDT), 并以基于线索暴露的渴求感测量为效度指标, 探讨了该类人群对海洛因延迟强化超快速折扣倾向及其心理机制。结果发现: (1) 相对于金钱延迟强化, 戒除者对海洛因延迟强化表现出显著的超快速折扣倾向, 且该倾向不随戒除期的延长而改变; (2) 戒除者对海洛因延迟强化的超快速折扣行为可能是其冲动性特质与海洛因相关线索共同作用的结果, 海洛因相对于金钱折扣率的增量部分可能反映了海洛因及其相关线索对该类人群主观渴求感的诱发效应。     

时间贴现的性质与脑机制

时间贴现是指个人对事件的价值量估计随着时间的流逝而下降的心理现象,它是行为选择理论的一个重要组成部分。着重介绍了时间贴现的数学模型（指数模型、双曲线模型族、非双曲线模型）、时间贴现现象和概率贴现现象的联系、延迟兑现与提前兑现时间贴现不对称现象及其理论解释,还讨论了时间贴现现象的神经机制研究。提出了时间贴现未来研究的几个主要问题     

Diminishing marginal value as delay discounting.

The fundamental law underlying economic demand and exchange is the tendency for value of marginal units to diminish with increasing amounts of a commodity. The present paper demonstrates that this law follows from three still-more-basic psychological assumptions: (a) limited consumption rate, (b) delay discounting, and (c) choice of highest valued alternative. Cases of diminishing marginal value apparently due to pure intensity of reward may plausibly be attributed to the above three factors. The further assumption that maximum consumption rate may vary within and across individuals implies that some substances may be unusually addictive and that some individual animals may be unusually susceptible to addiction.     

跨期选择的认知机制与神经基础

跨期选择是指个体对发生在不同时间的成本与收益进行权衡的决策过程。跨期选择的计算模型从经济学的角度用数学模型来建构时间折扣函数,而认知成分模型则从心理学的角度来研究跨期选择中的心理效应与认知成分。跨期选择的神经基础有三种不同的研究取向：双机制加工取向、单机制加工取向、自我控制取向。未来研究应该在跨期选择的认知机制、神经通路及运行机制、跨期选择的应用,以及从进化的角度对人与动物的跨期选择行为进行更深入的研究。     

Building blocks of self-control: increased tolerance for delay with bundled rewards

Impulsive choice can be defined as temporary preference for a smaller-sooner reward (SS) over a larger-later reward (LL). Hyperbolic discounting implies that impulsive choices will occur less when organisms choose between a series of SSs versus LLs all at once than when they choose between single SS versus LL pairs. Eight rats were exposed to two conditions of an intertemporal choice paradigm using sucrose solution as reward. In both conditions, the LL was 150 microl delayed by 3 s, while the SS was an immediate reward that ranged from 25-150 microl across sessions. Preference for the LL was greater when the chosen reward was automatically delivered three times in succession (bundled) than when it was chosen singly and delivered after each choice. For each of the 8 rats, the estimated SS amount that produced indifference was higher in the bundled condition than in the single condition. Because bundling in humans may be based on the perception that one's current choice is predictive of future choices, the data presented here may demonstrate an important building block of self-control.     

Waiting When Both Certainty and Magnitude Are Increasing: Certainty Overshadows Magnitude

In everyday decision making, people often face decisions with outcomes that differ on multiple dimensions. The trade‐off in preferences between magnitude, temporal proximity, and probability of an outcome is a fundamental concern in the decision‐making literature. Yet, their joint effects on behavior in an experience‐based decision‐making task are understudied. Two experiments examined the relative influences of the magnitude and probability of an outcome when both were increasing over a 10‐second delay. A first‐person shooter video game was adapted for this purpose. Experiment 1 showed that participants waited longer to ensure a higher probability of the outcome than to ensure a greater magnitude when experienced separately and together. Experiment 2 provided a precise method of comparing their relative control on waiting by having each increase at different rates. Both experiments revealed a stronger influence of increasing probability than increasing magnitude. The results were more consistent with hyperbolic discounting of probability than with cumulative prospect theory's decision weight function. Copyright © 2014 John Wiley & Sons, Ltd.