Estimation of the Coefficient of Variation with Minimum Risk: A Sequential Method for Minimizing Sampling Error and Study Cost

The coefficient of variation is an effect size measure with many potential uses in psychology and related disciplines. We propose a general theory for a sequential estimation of the population coefficient of variation that considers both the sampling error and the study cost, importantly without specific distributional assumptions. Fixed sample size planning methods, commonly used in psychology and related fields, cannot simultaneously minimize both the sampling error and the study cost. The sequential procedure we develop is the first sequential sampling procedure developed for estimating the coefficient of variation. We first present a method of planning a pilot sample size after the research goals are specified by the researcher. Then, after collecting a sample size as large as the estimated pilot sample size, a check is performed to assess whether the conditions necessary to stop the data collection have been satisfied. If not an additional observation is collected and the check is performed again. This process continues, sequentially, until a stopping rule involving a risk function is satisfied. Our method ensures that the sampling error and the study costs are considered simultaneously so that the cost is not higher than necessary for the tolerable sampling error. We also demonstrate a variety of properties of the distribution of the final sample size for five different distributions under a variety of conditions with a Monte Carlo simulation study. In addition, we provide freely available functions via the MBESS package in R to implement the methods discussed.     

社会心理学中的启动研究:范式与挑战

启动效应被严格界定为先前刺激对后续无关情境中的行为反应产生的无意识影响,而且启动对象应是某种认知表征或思维过程。启动研究最早源于认知心理学领域,后被用于社会心理学研究中,并逐渐发展出概念启动、心理定势启动和序列启动三大启动范式及诸多新技术。已有研究存在启动术语混淆和实验者效应等内外部效度问题,其中最大的争议为启动研究结果的可重复性问题。未来研究应致力于解决这些问题,并探讨启动的作用机制。     

Mixing virtue and vice: combining the immediacy effect and the diversification heuristic

Many of the most significant choices that people make are between vices, which exchange small immediate rewards for large delayed costs, and virtues, which exchange small immediate costs for large delayed rewards. We investigate the consequences of making a series of such choices either simultaneously or sequentially. We made two predictions. First, because many alternatives chosen under simultaneous choice will only be experienced following a delay, and because hyperbolic time discounting predicts that people will prefer delayed virtues but immediate vices, we predicted that people would choose more virtues in simultaneous than sequential choice. Second, due to the tendency to diversify portfolios of choices, we predicted a greater mix of virtues and vices in simultaneous than sequential choice. These predictions were confirmed in two experiments involving real choices; one between ‘highbrow’ and ‘lowbrow’ movies, and the other between ‘instant‐win’ and ‘prize‐draw’ lottery tickets. We conclude by posing the question of whether simultaneous or sequential choice results in decisions that more closely approximate what people ‘really’ want. Copyright © 1999 John Wiley & Sons, Ltd.     

The test taker's fallacy: How students guess answers on multiple‐choice tests

Many students and applicants take multiple‐choice tests to demonstrate their competence and achievement. When they are unsure, they guess the most likely answer to maximize their score. Despite the impact of guessing on test reliability and individual performance, studies have not examined how patterns of answer sequences in multiple‐choice tests affect guessing. This research presents the test taker's fallacy, which refers to an individual's tendency to expect a different answer to appear for the next question given a run of the same answer choices. The test taker's fallacy exhibits negative recency, similar to the gambler's fallacy. However, extending the sequential judgment literature, the test taker's fallacy shows that negative recency arises even when sequences may or may not be randomly generated. In three studies, including a survey and experiments, the test taker's fallacy is robustly observed. The test taker's fallacy is consistent with the operation of the representativeness heuristic. This research explains what and how test takers guess given a streak of answers and extends judgment under uncertainty to the test‐taking context.     

Suspects' consistency in statements concerning two events when different question formats are used

Lie detection research has typically focused on reports about a single event. However, in many forensic and security contexts, suspects are likely to report on several events, some of them may be untruthful. This presents interviewers with the challenge of detecting which reports are true and which are not. Varying question format in a second interview, we examined differences in liars' and truth‐tellers' statement consistency about two events. One hundred and fifty participants viewed a meeting in which a noncritical and a critical event were discussed. Truth‐tellers were instructed to be honest in their reports about both events, whereas liars had to lie about the critical event. In the first interview, all participants provided a free recall account. In a second interview, participants either gave another free recall account or responded to specific questions presented sequentially (concerning one event at a time) or nonsequentially (concerning both events simultaneously). Liars' accounts featured fewer repetitions than truth‐tellers for both events, particularly in response to questions presented in nonsequential order. The implications for the use of this question format are discussed.     

连续性公共物品困境中信息结构对决策行为的影响

选取240名大学二年级的学生,通过局域网信息反馈,进行了模拟投资的小组实验。结果发现,1、在连续性公共物品困境和自协调序列规则下,先前决策者的合作行为在决策的早期和中期起到了明显的榜样示范作用,并导致后续决策者的合作行为增加;2、这种示范作用在决策后期不起作用,被试出于搭便车或者担心自己利益受损的心理会表现出较高的竞争行为;3、先前决策者的竞争行为在整个决策过程中都起到明显的示范作用,使后续决策者的合作率保持在较低的水平;4、在没有任何信息反馈的情况下,被试倾向于在初期就做出投资决策,并表现出一定程度的合作行为。     

Framing and the Role of the Second Actor: An Application of Prospect Theory to Bargaining

An actor's frame of reference significantly affects that actor's risk attitude. Although the frame of reference is often taken as a given, earlier work shows it to be the result of an actor's assumptions and beliefs, which can be manipulated by a second actor in a bargaining situation. As modeled here, confidence in selected assumptions can be manipulated by one of two means: changing the confidence of the actor about the future domain, and getting the actor to adopt a particular domain by discounting the utility of a course of action. Both methods force a change in the perceived domain and a shift in risk attitude. In addition to showing manipulation of an actor's frame, the model adds to our understanding of Kahneman and Tversky's original expression of prospect theory.     

Negotiation, Persuasion and Argument

Argument is often taken to deal with conflicting opinion or belief, while negotiation deals with conflicting goals or interests. It is widely accepted that argument ought to comply with some principles or norms. On the other hand, negotiation and bargaining involve concession exchange and tactical use of power, which may be contrasted with attempts to convince others through argument. However, there are cases where it is difficult to draw a clear distinction between bargaining and argument: notably cases where negotiators persuade others through `framing' and cases where the aims of negotiation have to do with public assertion and acceptance. Those cases suggest that the distinction between negotiation and argument is not absolute, and this raises the question whether rules about what is acceptable in argument and rules about what is acceptable in negotiation can all be viewed as instances of more general common norms about human interaction.