Risky choice as a function of amount and variance in food supply.

In Experiment 1, 4 rats earned their daily food ration by choosing on a trials basis between a "risky" and a "riskless" lever. The risky lever produced either 15 45-mg food pellets or no pellets, and on average provided five pellets per choice. The riskless lever always produced three pellets. Across conditions, the number of trials per session was varied. Body weight and choice of the risky lever decreased as the number of trials per session decreased, even though body weight could only be defended by increased choice of the risky lever. In Experiment 2, trials per session were fixed, but the number of pellets delivered by the risky and riskless levers was either at the same level as in Experiment 1 or tripled from those levels. Now choice of the risky lever was inversely related to the size of reinforcement and to body weight. The results of these experiments show that risk aversion covaries with the amount of food available in a session and the daily variance in the amount of food earned.     

自我框架、风险认知和风险选择

对行为决策中“框架效应”(Framing Effect)的研究进行了拓展：探讨了自我框架对风险决策的影响及其机制。面对运用图示方法表示的管理,健康,及投资方面的风险决策问题,参与者自主地选择对方案的描述（自我框架）。研究有四个主要发现：1）自我框架对风险选择的效应部分显著,而且对风险选择的影响方向因情境的不同而不同;2）机会威胁认知是自我框架效应的一个中介变量;3）自我框架在情绪语气上的差异对风险决策有显著影响：决策者对一个备选方案（确定性或风险性方案）相对于另一个备选方案的自我描述的情绪语气越积极正面,这个方案被选择的可能性越大;4）决策者的机会-威胁认知是这一自我框架效应的部分中介变量。也就是说,对备选方案的自我描述语气作为一种对决策信息的编码影响了风险（机会和威胁）认知,进而影响决策者的风险偏好和选择     

How Affect Shapes Risky Choice: Distorted Probability Weighting Versus Probability Neglect

People's choices between prospects with relatively affect‐rich outcomes (e.g., medical side effects) can diverge markedly from their choices between prospects with relatively affect‐poor outcomes (e.g., monetary losses). We investigate the cognitive mechanisms underlying this “affect gap” in risky choice. One possibility is that affect‐rich prospects give rise to more distortion in probability weighting. Another is that they lead to the neglect of probabilities. To pit these two possibilities against each other, we fitted cumulative prospect theory (CPT) to the choices of individual participants, separately for choices between options with affect‐rich outcomes (adverse medical side effects) and options with affect‐poor outcomes (monetary losses); additionally, we tested a simple model of probability neglect, the minimax rule. The results indicated a qualitative difference in cognitive mechanisms between the affect‐rich and affect‐poor problems. Specifically, in affect‐poor problems, the large majority of participants were best described by CPT; in affect‐rich problems, the proportion of participants best described by the minimax rule was substantially higher. The affect gap persisted even when affect‐rich outcomes were supplemented by numerical information, thus providing no support for the thesis that choices in affect‐rich and affect‐poor problems diverge because the information provided in the former is nonnumerical. Our findings suggest that the traditional expectation‐based framework for modeling risky decision making may not readily generalize to affect‐rich choices. Copyright © 2015 John Wiley & Sons, Ltd.     

Choice and the rate of punishment in concurrent schedules

Rats' responses on two levers were reinforced according to independent random-interval 1.5-min food schedules. In addition, both lever presses were intermittently punished according to several concurrent random-interval random-interval shock schedules. For the left, the scheduled rate of punishment was kept constant according to a random-interval 6-min schedule. For the right, the rate of punishment varied. As the frequency of punishment for the right lever press increased, its rate decreased. The rate of the left punished lever press increased, however, even though its scheduled reinforcement rate and punishment rate remained unchanged.     

睡眠剥夺影响风险决策的双系统模型探讨

睡眠剥夺是指由于环境或自身原因无法满足正常睡眠时间的情况。大量实证研究发现, 睡眠剥夺会导致个体在风险决策中更倾向于风险寻求, 同时也有研究表明睡眠剥夺会导致个体风险规避, 而目前尚无统一结论。睡眠剥夺从风险感知、风险容忍、风险决策策略三个方面影响了风险决策, 其心理机制可由认知和情绪双路径模型进行解释, 且脑神经生理学研究也提供了相关证据。未来的研究应该进一步关注：(1)现实工作生活中的睡眠不足对风险决策的影响; (2)睡眠剥夺影响风险决策的理论模型建构。     

Choice and segmented interreinforcement intervals

Pigeons were trained on a two-key concurrent schedule, where food reinforcers on one key were arranged by a simple variable-interval schedule and on the other key by a chain variable-interval variable-interval schedule. When the initial link of the chain was in effect, the pigeons tended to respond more on the simple variable-interval schedule, and hence less on the chain, than would be expected from a comparison of both the local and overall rates of reinforcement of the two schedules. When the terminal link of the chain was in effect, the pigeons responded more on the chain than would be expected from a comparison of the rates of reinforcement of the schedules then in effect. Overall responding on the chain was not proportional to overall reinforcement on the chain but rather was a by-product of responding during initial- and terminal-link phases.     

Choice and reinforcement delay

Previous studies of choice between two delayed reinforcers have indicated that the relative immediacy of the reinforcer is a major determinant of the relative frequency of responding. Parallel studies of choice between two interresponse times have found exceptions to this generality. The present study looked at the choice by pigeons between two delays, one of which was always four times longer than the other, but whose absolute durations were varied across conditions. The results indicated that choice is not uniquely determined by the relative immediacy of reinforcement, but that absolute delays are also involved. Models for concurrent chained schedules appear to be more applicable to the present data than the matching relation; however, these too failed to predict choice for long delays.     

Choice as a dependent measure in autoshaping: sensitivity to frequency and duration of food presentation.

Previous investigations have shown that rate, latency, and percentage of trials with at least one response are somewhat insensitive measures of the strength of autoshaped responding. In the present studies, these measures were contrasted with the allocation of responding during simultaneous choice tests, a measure of response strength frequently used in operant paradigms. In two experiments, nine pigeons were exposed to a forward pairing autoshaping procedure. Training sessions consisted of the successive presentation of three stimuli, each followed by food on either 100%, 50%, or 0% of the trials. Choice testing involved the simultaneous presentation of the three stimuli. In Experiment I, all pigeons consistently directed their initial choice responses and the majority of subsequent responses to the stimulus always followed by food, despite the fact that during training sessions the response rates of most birds were highest in the presence of the stimulus followed by food on 50% of the trials. In Experiment II, rate, latency, and percentage of trials with at least one response did not change appreciably as a function of duration of feeder presentations. However, choice responding was lawfully affected by duration of feeder presentations. These data suggest that choice is perhaps a more sensitive measure of the strength of autoshaped responding than other, more commonly employed, indices.     

Eyes on the Prize? Evidence of Diminishing Attention to Experienced and Foregone Outcomes in Repeated Experiential Choice

Recently, there has been increased interest in decisions‐from‐experience (where decision makers learn from observing the outcomes of previous choices), which provide valuable insights into the learning and preference construction processes underlying many daily decisions. Several process models have been developed to capture these processes, and while such models often fit the data well, many assume that the decision maker is a vigilant observer, processing each outcome. In two studies, we provide a critical test of this assumption using eye tracking to record directed visual attention when participants choose repeatedly among two options, each time being shown the outcome for their chosen option and for the foregone option. Consistently, we find that the vigilance assumption is not supported, with decision makers often not attending to outcome information. Moreover, (in)attention to outcomes is predictable, with vigilance decreasing as more choices are made, and being greater for obtained than for foregone outcomes, and when options deliver only gains as opposed to losses or a mixture of gains and losses. Furthermore, we find that this variation in attentional allocation plays a central role in the apparent indecisiveness (inconsistency) in choice, with increased attention to foregone outcomes predicting switches to that option on the next choice. Together, these findings highlight the value of eye tracking in investigations of decisions‐from‐experience, providing novel insight into the cognitive processes underlying them. Copyright © 2015 John Wiley & Sons, Ltd.     

Probability and delay in commitment

In the first stage of a two-stage choice, human subjects chose between probabilistic access to a second choice (between a small high-probability reward and a large low-probability reward) and commitment to the large low-probability reward. When confronted with the second-stage choice, subjects strongly preferred the small high-probability reward. When the first-stage probability (of access to the second stage) was high, subjects strongly preferred the path leading to the choice in the second stage. But when the first-stage probability was low, subjects committed themselves to the large low-probability reward. These results parallel those obtained by Rachlin and Green (1972) with pigeons and constitute some evidence that probabilities may be interpreted as delays.     

Choice,Conditioned Reinforcement,and the Prius Effect

Psychologists have long been intrigued with the rationales that underlie our decisions. Similarly, the concept of conditioned reinforcement has a venerable history, particularly in accounting for behavior not obviously maintained by primary reinforcers. The studies of choice and of conditioned reinforcement have often developed in lockstep. Many contemporary approaches to these fundamental topics share an emphasis on context and on relative value. We trace the evolution of thinking about the potency of conditioned reinforcers from stimuli that were thought to acquire their value from pairings with more fundamental reinforcers to stimuli that acquire their value by being differentially correlated with these more fundamental reinforcers. We discuss some seminal experiments (including several that have been underappreciated) and some ongoing data, all of which have propelled us to the conclusion that the strength of conditioned reinforcers is determined by their signaling a relative improvement in the organism''s relation to reinforcement.