Observed Variability and Values Matter: Toward a Better Understanding of Information Search and Decisions from Experience

The search for different options before making a consequential choice is a central aspect of many important decisions, such as mate selection or purchasing a house. Despite its importance, surprisingly little is known about how search and choice are affected by the observed and objective properties of the decision problem. Here, we analyze the effects of two key properties in a binary choice task: the options' observed and objective values, and the variability of payoffs. First, in a large public data set of a binary choice task, we investigate how the observed value and variability relate to decision‐makers' efforts and preferences during search. Furthermore, we test how these properties influence the chance of correctly identifying the objectively maximizing option, and how they affect choice. Second, we designed a novel experiment to systematically analyze the role of the objective difference between the options. We find that a larger objective difference between options increases the chance for correctly identifying the maximizing option, but it does not affect behavior during search and choice. Copyright © 2013 John Wiley & Sons, Ltd.     

视觉工作记忆负载对偏差干扰调控的ERP研究

采用事件相关电位技术（ERPs）,对听视跨通道不同工作记忆负载下偏差干扰效应的加工机制进行研究。当视觉线索50%时,比较有无工作记忆负载条件下偏差干扰效应,分析偏差刺激与标准刺激诱发的差异波,结果发现：（1）存在工作记忆负载和偏差干扰效应;（2）有无工作记忆负载下差异波均出现明显的N1/MMN成分、NP3和RON成分;（3）差异波中N1/MMN成分的平均波幅和潜伏期均没有差异,NP3成分的平均波幅下降;RON成分在平均波幅上没有差异,潜伏期上有工作记忆负载下显著小于无工作记忆负载。研究表明视觉工作记忆负载对偏差干扰调控过程的神经机制并不会因为无关信息与相关信息间冲突竞争增强而改变。     

CAT选题策略分类概述

选题是计算机化自适应测验（CAT）测试过程的关键环节,选题策略的目标是要达到较高的测量精度,同时也实现试题曝光率控制及其他测验目标的实现.本文根据选题策略的基本原理和衍生发展,将众多CAT选题策略分为五大选题策略系列：Fisher函数系列、K-LI函数系列、α分层系列、贝叶斯系列、b匹配系列;并根据测验目标（测验精度、试题曝光率控制、内容平衡、多条件约束）对这些选题策略进行了细分,并对CAT选题策略的选择思路进行归纳.     

记忆集对注意焦点转换及其返回抑制的影响

采用记忆更新任务,实验1要求被试分别更新3个和4个记忆项目,并设置不转换、控制转换和抑制转换条件,考察记忆集对注意焦点转换及其返回抑制的影响;实验2操纵两次更新同一记忆项目之间对其它记忆项目更新的次数（2次、3次及3次以上）,在实验1基础上,考察返回抑制中项目抑制状态的消退过程.结论：随记忆集增加,转换代价增大,而返回抑制效应消失;当注意焦点对其它记忆项目更新2次时,之前被抑制项目的抑制状态可完全消退.     

Executive functions,impulsivity, and inhibitory control in adolescents: A structural equation model

Background. Adolescence represents a critical period for brain development, addressed by neurodevelopmental models to frontal, subcortical-limbic, and striatal activation, a pattern associated with rise of impulsivity and deficits in inhibitory control. The present study aimed at studying the association between self-report measures of impulsivity and inhibitory control with executive function in adolescents, employing structural equation modeling. Method. Tests were administered to 434 high school students. Acting without thinking was measured through the Barratt Impulsiveness Scale and the Dickman Impulsivity Inventory, reward sensitivity through the Behavioral Activation System, and sensation seeking through the Zuckerman–Kuhlman–Aluja Personali- ty Questionnaire. Inhibitory control was assessed through the Behavioral Inhibition System. The performance at the Wisconsin Card Sorting Task indicated executive function. Three models were specified using Sample Covariance Matrix, and the estimated parameters using Maximum Likelihood. Results. In the final model, impulsivity and inhibitory control predicted executive function, but sensation seeking did not. The fit of the model to data was excellent. Conclusions. The hypothesis that inhibitory control and impulsivity are predictors of executive function was supported. Our results appear informative of the validity of self-report measures to examine the relation between impulsivity traits rather than others to regulatory function of cognition and behavior.     

Visual attribute modulates the time course of iconic memory decay

Studies on iconic memory demonstrate that rich information from a visual scene quickly becomes unavailable with the passage of time. The decay rate of iconic memory refers to the dynamics of memory availability. The present study investigated the iconic memory decay of different stimulus attributes that comprised an object. Specifically, in Experiment 1, participants were presented with eight coloured numbers (e.g., red 4) and required to remember only one attribute, either colour or number, over different blocks of trials. The participants then reported the cued attribute in which the cue Stimulus Onset Asynchrony (SOA) from the memory array onset was varied (0, 100, 200, 300, 500, and 1000?ms). We found that numerical information became unavailable more quickly than colour information, despite the fact that the memory accuracies at 0 and 1000?ms SOAs were comparable between the two attributes. In Experiment 2, we replicated the finding that a numerical representation was lost more quickly than a colour representation when visual masks followed the target stimulus. These results suggest that the various visual attributes comprising an object are lost over time at different rates in iconic memory. We discuss this finding in relation to how perceptual representation is transferred to the capacity-limited visual working memory.     

Object representations are biased toward each other through statistical learning

The visual system is remarkably efficient at extracting regularities from the environment through statistical learning. While such extraction has extensive consequences on cognition, it is unclear how statistical learning shapes the representations of the individual objects that comprise the regularities. Here we examine how statistical learning alters object representations. In three experiments, participants were exposed to either random arrays containing objects in a random order, or structured arrays containing object pairs where two objects appeared next to each other in fixed spatial or temporal configurations. After exposure, one object in each pair was briefly presented and participants judged the location or the orientation of the object without seeing the other object in the pair. We found that when an object reliably appeared next to another object in space, it was judged as being closer to the other object in space even though the other object was never presented (Experiments 1 and 2). Likewise, when an object reliably preceded another object in time, its orientation was biased toward the orientation of the other object even though the other object was never presented (Experiment 3). These results demonstrated that statistical learning fundamentally shapes how individual objects are represented in visual memory, by biasing the representation of one object toward its co-occurring partner. Importantly, participants in all experiments were not explicitly aware of the regularities. Thus, the bias in object representations was implicit. The current study reveals a novel impact of statistical learning on object representation: spatially co-occurring objects are represented as being closer in space, and temporally co-occurring objects are represented as having more similar features.