Effects of time between trials on rats' and pigeons' choices with probabilistic delayed reinforcers

Parallel experiments with rats and pigeons examined reasons for previous findings that in choices with probabilistic delayed reinforcers, rats' choices were affected by the time between trials whereas pigeons' choices were not. In both experiments, the animals chose between a standard alternative and an adjusting alternative. A choice of the standard alternative led to a short delay (1 s or 3 s), and then food might or might not be delivered. If food was not delivered, there was an "interlink interval," and then the animal was forced to continue to select the standard alternative until food was delivered. A choice of the adjusting alternative always led to food after a delay that was systematically increased and decreased over trials to estimate an indifference point--a delay at which the two alternatives were chosen about equally often. Under these conditions, the indifference points for both rats and pigeons increased as the interlink interval increased from 0 s to 20 s, indicating decreased preference for the probabilistic reinforcer with longer time between trials. The indifference points from both rats and pigeons were well described by the hyperbolic-decay model. In the last phase of each experiment, the animals were not forced to continue selecting the standard alternative if food was not delivered. Under these conditions, rats' choices were affected by the time between trials whereas pigeons' choices were not, replicating results of previous studies. The differences between the behavior of rats and pigeons appears to be the result of procedural details, not a fundamental difference in how these two species make choices with probabilistic delayed reinforcers.     

Modeling the effect of reward amount on probability discounting

The present study with college students examined the effect of amount on the discounting of probabilistic monetary rewards. A hyperboloid function accurately described the discounting of hypothetical rewards ranging in amount from $20 to $10,000,000. The degree of discounting increased continuously with amount of probabilistic reward. This effect of amount was not due to changes in the rate parameter of the discounting function, but rather was due to increases in the exponent. These results stand in contrast to those observed with the discounting of delayed monetary rewards, in which the degree of discounting decreases with reward amount due to amount-dependent decreases in the rate parameter. Taken together, this pattern of results suggests that delay and probability discounting reflect different underlying mechanisms. That is, the fact that the exponent in the delay discounting function is independent of amount is consistent with a psychophysical scaling interpretation, whereas the finding that the exponent of the probability-discounting function is amount-dependent is inconsistent with such an interpretation. Instead, the present results are consistent with the idea that the probability-discounting function is itself the product of a value function and a weighting function. This idea was first suggested by Kahneman and Tversky (1979), although their prospect theory does not predict amount effects like those observed. The effect of amount on probability discounting was parsimoniously incorporated into our hyperboloid discounting function by assuming that the exponent was proportional to the amount raised to a power. The amount-dependent exponent of the probability-discounting function may be viewed as reflecting the effect of amount on the weighting of the probability with which the reward will be received.     

A Fuzzy Goal Programming Formulation with Multiple Target Levels

The essential activity of a manager is decision making, which is becoming more and more complex, mainly in the multi‐criteria problems. Multi‐choice goal programming (MCGP) is considered as a robust tool in operational research to solve this type of problem. However, in real world problems, determining precise targets for the goals is a difficult task. To deal with such situation, Tabrizi introduced and used in 2012 the concept of membership functions in the MCGP model in order to model the targets fuzziness of each goal. In their model, they considered just only one type of functions (triangular form), which does not reflect adequately the decision maker's preferences that are considered as an essential element for modelling the goal's fuzziness. Their model is called Fuzzy MCGP. In this paper, new ideas are presented to reformulate MCGP model to tackle all types of functions by introducing the (decision maker's) preferences. The concept of indifference thresholds is used in the new formulation for characterizing the imprecision and the preferences associated with all types of the goals. The proposed formulation provides useful insight about the solution of a new class of problems. A numerical example is given to demonstrate the validity and strength of the new formulation. Copyright © 2013 John Wiley & Sons, Ltd.     

首词素位置概率信息未参与汉语阅读的词切分：基于副中央凹加工的证据

本研究采用边界范式,考察汉语阅读中读者是否在副中央凹处利用首词素的位置概率信息进行词切分和词识别。采用2（首词素位置概率：高、低）×２（预视类型：相同预视、假字预视）的被试内实验设计,以双字词为目标词,记录大学生阅读句子时的眼动轨迹。结果发现,在跳读率和第一遍阅读的眼动指标中,被试在高、低首词素位置概率条件中获得的预视效益量无显著差异。该结果表明,读者并未在副中央凹处加工首词素的位置概率信息。结合前期研究推断,首词素位置概率信息没有作用于汉语阅读的词切分和词识别。     

Sometimes it does hurt to ask: The constructive role of articulating impressions

Decisions can sometimes have a constructive role, so that the act of, for example, choosing one option over another creates a preference for that option (e.g., , ,  and ). In this work we explore the constructive role of just articulating an impression, for a presented visual stimulus, as opposed to making a choice (specifically, the judgments we employ are affective evaluations). Using quantum probability theory, we outline a cognitive model formalizing such a constructive process. We predict a simple interaction, in relation to how a second image is evaluated, following the presentation of a first image, depending on whether there is a rating for the first image or not. The interaction predicted by the quantum model was confirmed across three experiments and a variety of control manipulations. The advantages of using quantum probability theory to model the present results, compared with existing models of sequence order effects in judgment (e.g., Hogarth & Einhorn, 1992) or other theories of constructive processes when a choice is made (e.g.,  and ) are discussed.     

On the logical structure of de Finetti's notion of event

This paper sheds new light on the subtle relation between probability and logic by (i) providing a logical development of Bruno de Finetti's conception of events and (ii) suggesting that the subjective nature of de Finetti's interpretation of probability emerges in a clearer form against such a logical background. By making explicit the epistemic structure which underlies what we call Choice-based probability we show that whilst all rational degrees of belief must be probabilities, the converse doesn't hold: some probability values don't represent decision-relevant quantifications of uncertainty.     

Reinforcer pathology,probabilistic choice,and medication adherence in patients with multiple sclerosis

The reinforcer pathology model posits that core behavioral economic mechanisms, including delay discounting and behavioral economic demand, underlie adverse health decisions and related clinical disorders. Extensions beyond substance use disorder and obesity, however, are limited. Using a reinforcer pathology framework, this study evaluates medical adherence decisions in patients with multiple sclerosis. Participants completed behavioral economic measures, including delay discounting, probability discounting, and a medication purchase task. A medical decision-making task was also used to evaluate how sensitivity to mild side effect risk and efficacy contributed to the likelihood of taking a hypothetical disease-modifying therapy. Less steep delay discounting and more intense (greater) medication demand were independently associated with greater adherence to the medication decision-making procedure. More generally, the pattern of interrelations between the medication-specific and general behavioral economic metrics was consistent with and contributes to the reinforcer pathology model. Additional research is warranted to expand these models to different populations and health behaviors, including those of a positive health orientation (i.e., medication adherence).     

Evaluating the effectiveness of employee assistance programmes: a systematic review

The rapid growth of employee assistance Programmes (EAPs) has not been matched by the accompanying research base of their efficacy. Given the inconsistent information relating to the effectiveness of EAPs in enhancing employee and organizational outcomes, the present review systematically appraised available evidence from organizational psychology and business databases and grey literature sources. A total of 17 studies examining the impact of EAPs, met the inclusion criteria. These were mostly from North America and utilized quantitative methodology and pre- and post-intervention designs. The majority of studies focused on EAPs offered by external providers and the counselling service, with the most common limitations being discrepancies in variable definitions and an absent comparable control group. Overall, this review found that utilizing EAPs enhanced employee outcomes, specifically improving levels of presenteeism and functioning. Absenteeism was most commonly investigated but produced mixed results. Presenteeism demonstrated a stronger effect size and greater improvement than absenteeism, suggesting presenteeism as a better variable for assessing EAP effectiveness. This review clarified parameters of existing evidence and highlighted the narrow range of measures used to date, omitting important constructs such as health and well-being and productivity. A broader evaluation capturing a wider range of variables is urgently needed.     

Modeling effects of risk and social distance on vaccination choice

Despite vaccines' consistently demonstrated effectiveness, vaccination rates remain suboptimal due to vaccine refusal. Low vaccination rates are particularly problematic for individuals who cannot be vaccinated for medical reasons and thus must rely on herd immunity (i.e., protection of vulnerable individuals due to the high rate of vaccination of other—often socially distant—individuals). The current study uses a novel decision‐making task to examine how three variables impacted participants' highest acceptable probability of side effects to their children: 1) the severity of the side effects their children experience, 2) the social distance to the beneficiary of the vaccination, and 3) the probability that the vaccine will prevent disease for that designated beneficiary. Participants' willingness to risk potential side effects of vaccination systematically decreased as the 1) effectiveness of the vaccination decreased, 2) the beneficiary of the vaccination became more socially distant, and 3) the severity of side effects increased. These data were well‐described by behavioral economic models used to examine the discounting of other health behavior.