STEADY-STATE ASSESSMENT OF IMPULSIVE CHOICE IN LEWIS AND FISCHER 344 RATS: BETWEEN-CONDITION DELAY MANIPULATIONS

Previous research has shown that Lewis rats make more impulsive choices than Fischer 344 rats. Such strain-related differences in choice are important as they may provide an avenue for exploring genetic and neurochemical contributions to impulsive choice. The present systematic replication was designed to determine if these findings could be reproduced using a procedure less susceptible to within- or between-session carry-over effects that may have affected previous findings. Specifically, delays to the larger–later food reinforcer were manipulated between conditions following steady-state assessments of choice, and the order of delays across conditions was mixed. The results confirmed previous findings that Lewis rats made significantly more impulsive choices than Fischer 344 rats. Fischer 344 rats' preference for the larger–later reinforcer, on the other hand, was less extreme than reported in prior research, which may be due to carry-over effects inherent to the commonly used technique of systematically increasing delays within session. Previously reported across-strain motor differences were reproduced as Lewis rats had shorter latencies than Fischer 344 rats, although these latencies were not correlated with impulsive choice. Parallels between reduced dopamine function in Lewis rats and clinical reports of impulse-control disorders following treatment of Parkinson patients with selective D2/D3 dopamine agonists are discussed.     

Temporal Discounting Mechanisms of Future‐oriented Coping: Evidence from Delay Discounting and Task Prioritization Paradigms

Four studies were conducted to examine the relationship between future‐oriented coping and temporal discounting under different situational conditions. In Study 1, 138 participants were primed with either stressful or neutral stimuli, followed by a delay‐discounting task. In Study 2, 118 participants were primed with either stressful or neutral stimuli, followed by a task‐prioritization activity. The results of both studies indicated that future‐oriented coping had a significant negative association with temporal discounting or the number of rational choices in the neutral‐priming condition, but the relationship was not significant in the stress‐priming condition. In Study 3, qualitative data revealed that the major reason for shifting choices from larger but later payoffs to smaller but sooner rewards in a stressful condition was to reduce the stressful mood, create a positive mood, and promote a sense of accomplishment. This explanation was corroborated by Study 4, in which one group was allowed to choose an immediate payoff and the other group was blocked from choosing that immediate payoff. We confirmed that post‐test anxiety was significantly lower in the immediate payoff group compared with the delayed‐payoff group in proactive and preventive coping, using pre‐test anxiety as a covariate. Preventive coping helped to reduce anxiety levels in a stressful condition only when there was a choice to obtain an immediate payoff. These findings underscore the relationship between future‐oriented coping and temporal discounting, as well as the flexibility of discounting in the face of stress. Copyright © 2015 John Wiley & Sons, Ltd.     

The strategies in past temporal discounting

对过去事件的加工涉及到对现在信息的加工,过去获得的价值能够为现在的生活带来的收益可能对过去事件的价值估计具有影响。本研究探讨了过去事件对现在生活的影响在过去时间贴现中的作用。采用延迟时间贴现范式任务,选取2周到50年共10个过去时间长度,要求被试在现在获得的奖金和过去获得的奖金之间进行偏好选择,并且完成对过去时间贴现决策策略的问题回答。采用曲线下的单位面积UAUr(t1,t1) 为过去时间贴现率,发现过去时间贴现率在过去2周和过去1个月之间[Z = 2.662,p = .008]、过去1年和过去3年之间[Z = 2.587, p = .010] 差异显著。对决策策略的回答进行内容分析(频次统计信度为0.875),发现过去事件能够为现在生活带来的收益影响了被试对过去事件的价值估计和偏好选择。从现在起到过去2周内,被试看重近的过去获得的奖金对现在的生活的帮助,偏好选择过去获得的奖金;在较远的过去,从过去2周起到过去1年内,奖金数量和获得奖金的时间之间的比例影响了被试的偏好选择;从过去1年起到过去50年内,远的过去获得的奖金对现在生活的影响微乎其微,被试偏好现在获得的奖金。本研究的结果支持了过去时间贴现和未来时间贴现具有不同的心理加工机制,并且有助于进一步了解过去时间的差别感受性的变化规律。     

The roles of delay and probability discounting in texting while driving: Toward the development of a translational scientific program

A sample of 109 college students completed a survey to assess how frequently they send or read text messages while driving. In a novel discounting task with a hypothetical scenario in which participants receive a text message while driving, they rated the likelihood of replying to a text message immediately versus waiting to reply until arriving at a destination. The scenario presented several delays to a destination and probabilities of a motor vehicle crash. The likelihood of waiting to reply decreased as a function of both the delay until the destination and the probability of a motor vehicle crash. Self‐reported higher frequencies of texting while driving were associated with greater rates of both delay and probability discounting. The degree of delay discounting was altered as a function of the probability of a motor vehicle crash and vice versa. These results suggest that both delay and probability discounting are important underlying mechanisms of drivers' decision to text while driving.     

The function of information immediacy and smartphone usage

The current study used the delay discounting method to understand the need to respond to different communication mediums. In this method, participants were asked their preference between responding immediately for a smaller reward or after a delay for a larger reward. Experiment 1 asked participants their preference for responding to a text message, sticky note, and postcard. Participants indicated lower willingness in responding to the text message but did not have differing preferences between the other mediums. Experiment 2 sought to understand if the effect was related specifically to text messages or all instantaneous communication. Participants indicated their preference for responding to a text message, email, and voicemail while driving on a road trip. Participants indicated no differences in preference for responding to the message mediums. These results have implications for interpreting distracted driving research, specifically texting and driving, as the effect may apply to other communication mediums.     

愤怒情绪对延迟折扣的影响：确定感和控制感的中介作用

本研究基于评估倾向理论, 通过3项实验考察了特定负性情绪(愤怒)对延迟折扣的影响, 并探究确定感和控制感评估倾向在这一关系中的作用。实验1考察愤怒情绪对延迟折扣的影响, 结果发现, 愤怒组被试的延迟满足倾向显著强于恐惧组和控制组。实验2采用实验因果链设计考察确定感和控制感评估倾向在愤怒情绪影响个体延迟折扣中的作用, 结果发现, 愤怒情绪可以有效增强个体的确定感和控制感(实验2a), 同时确定感和控制感能够增强个体的延迟满足倾向(实验2b)。实验3采用中介测量设计考察确定感和控制感评估倾向在愤怒情绪影响个体延迟折扣中的作用, 结果发现, 确定感和控制感评估倾向在愤怒情绪影响个体延迟折扣中起完全中介作用。本研究结果表明, 当个体进行跨期决策时, 体验到与确定感和控制感有关的偶然愤怒情绪会增强其延迟满足倾向。本研究对探究特定负性情绪对个体延迟折扣的影响具有一定的启示意义。     

A mechanism for reducing delay discounting by altering temporal attention

Rewards that are not immediately available are discounted compared to rewards that are immediately available. The more a person discounts a delayed reward, the more likely that person is to have a range of behavioral problems, including clinical disorders. This latter observation has motivated the search for interventions that reduce discounting. One surprisingly simple method to reduce discounting is an "explicit-zero" reframing that states default or null outcomes. Reframing a classical discounting choice as "something now but nothing later" versus "nothing now but more later" decreases discount rates. However, it is not clear how this "explicit-zero" framing intervention works. The present studies delineate and test two possible mechanisms to explain the phenomenon. One mechanism proposes that the explicit-zero framing creates the impression of an improving sequence, thereby enhancing the present value of the delayed reward. A second possible mechanism posits an increase in attention allocation to temporally distant reward representations. In four experiments, we distinguish between these two hypothesized mechanisms and conclude that the temporal attention hypothesis is superior for explaining our results. We propose a model of temporal attention whereby framing affects intertemporal preferences by modifying present bias.     

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.     

Gambling and Delay Discounting in Japanese Students

The present study examined the relationship between gambling behavior and delay discounting with Japanese residents. Japanese university students were selected into pathological gambler and non‐gambling control groups using a Japanese version of the South Oaks Gambling Screen. In a discounting task, participants chose individually between a large delayed reward and a smaller immediate reward with varied delays. The discounting rate (k‐value) and the area under the curve were significantly higher and smaller, respectively, for the gambler group than for the control group. These findings show that Japanese gamblers discount delayed rewards more steeply than non‐gambling controls, as has been found in U.S. residents.     

Future anhedonia and time discounting

The temporal location of an event influences the way people mentally represent that event. We suggest (a) that such representational differences can produce an affective forecasting error that we call future anhedonia, which is the belief that hedonic states will be less intense in the future than in the present, and (b) that future anhedonia plays a role in time discounting (i.e., the tendency to place a smaller present value on present events than on future events). Experiments 1a and 1b demonstrated that people are prone to future anhedonia, Experiments 2a and 2b ruled out artifactual alternatives, and Experiments 3a and 3b demonstrated that future anhedonia plays a role in time discounting. These studies suggest that one reason why people prefer to enjoy benefits in the present and pay costs in the future is that they do not realize how they will feel when those costs and benefits are actually experienced.