注意视觉搜索研究的新进展

一个时期以来有关注意视觉搜索的研究认为,注意是以系列搜索或平行搜索方式进行的.而Wolfe(1998)通过对10多年有关研究数据整理画出的坡度曲线图则表明,注意视觉搜索坡度的整体分布是没有波峰的,表明系列搜索或平行搜索理论是错误的.而且,他新近研究又表明注意视觉搜索同样遵循认知经济原则:自由无序扫描是比系统扫描更快发现项目的方式.     

网页设计中的人的视觉搜索因素

网页设计需要考虑到人的视觉加工机制,尤其是人的视觉搜索机制。网页信息的视觉呈现会影响人的视觉搜索效率,包括页面信息的密度特点,页面标签和页面结构,文本的分栏方式以及视觉刺激间的匹配。在网页设计时需要考虑到的人的视觉特征主要包括视觉搜索的位置特征,搜索模式,眼动特点以及视觉搜索的非对称性。     

视觉加工的双侧视野优势及其脑机制

等量的视觉任务呈现在双侧视野比仅仅呈现在单侧视野能够获得更好的任务表现, 这被称为双侧视野优势(bilateral field advantage BFA)。BFA产生于两个紧密连接的机制：枕叶视皮层内的竞争性相互作用及背侧额顶叶网络自上而下的注意调控。前者主要发生在V1–V4等与视网膜存在拓扑映射关系的视皮层区, 后者则主要涉及两侧的顶内沟、右侧楔前叶及额眼区。未来的研究可以进一步采用三维立体视觉材料探讨BFA, 考察它与其它视野效应间交互的脑机制, 同时也可尝试解决背侧额顶叶网络的各脑区在系统的功能连接方面尚存的争议。     

视觉搜索中基于工作记忆内容的注意捕获与抑制

注意是对有关信息的选择及对无关信息的抑制, 工作记忆是对有关信息的保持以及对无关信息的抑制, 两者在一定程度上都体现了选择性地指向与当前任务有关的刺激并同时抑制无关刺激。在系统地回顾已有研究的基础上结合新近的ERP研究, 从视觉搜索中基于工作记忆内容的注意捕获与注意抑制两个角度综述了视觉工作记忆与视觉选择性注意的相关研究。研究者们主要从两方面对该领域的问题进行了探讨：(1)视觉工作记忆内容对视觉选择性注意的导向作用; (2)视觉工作记忆内容对视觉选择性注意产生导向作用的条件。文章对以往的研究进行了总结, 指出了无论保持在视觉工作记忆的内容是捕获注意还是受到抑制, 都存在着自上而下和自下而上两种加工机制。     

视觉选择性注意加工的优先效应与加工模式

1　问题提出选择性注意是注意研究的核心问题。以往的注意研究提出了各种理论 ,不同理论及相关研究关注的主要问题是 :什么特征的信息更容易引起优先注意 ,即注意优先权(ＡｔｔｅｎｔｉｏｎａｌＰｒｉｏｒｉｔｙ)。影响注意优先权的因素主要包括线索提示与位置、分心刺激数量、目标特征、线索与目标的间隔时间、目标动态变化等。如Ｐｏｓｎｅｒ等研究发现中央线索与目标一致的反应时较不一致要快 ,注意的有效集中与有效线索指向的目标获得优先加工 ;Ｃｈｒｉｓｔｏｐｈｅｒ、Ｓｅａｒｓ等研究发现 ,有效跟踪的目标具有注意优先权 ;Ｙａｎｔ…     

发展性协调障碍儿童视觉通道前注意加工的特点：来自ERP的证据

研究表明发展性协调障碍儿童听觉通道的前注意受损,其视觉通道的前注意加工是否也存在缺陷,从而造成了信息加工困难,目前尚不清楚。本研究旨在探究发展性协调障碍儿童视觉通道前注意加工的特点。从小学二、三、四年级共760名学生中筛选出障碍组20名,同时选择年龄、智力水平相当的对照组儿童20名。采用非注意Oddball任务,以不同颜色图片为实验材料,比较两组儿童前注意信息加工能力。行为结果表明,在注意主任务上,两组儿童的反应时不存在差异;然而,障碍组儿童的准确率显著低于对照组。ERP结果表明,相比于对照组儿童,障碍组儿童的视觉失匹配负波(visual mismatch negativity, vMMN)潜伏期明显延长。同时,本研究还发现运动技能诊断量表得分与vMMN的潜伏期存在显著相关。结果提示,发展性协调障碍儿童视觉通道前注意加工可能存在缺陷;vMMN潜伏期可作为初步评估和判断发展性协调障碍的脑电指标。     

数字加工的脑功能成像研究进展及其皮层定位

数字加工是人类最重要的认知功能之一。当前的脑功能成像研究有助于对数字加工与皮层之间的联系进行更精确的定位。基于对上世纪80年代来有关数字加工脑功能成像研究的主要成果的回顾,尤其是一些重要区域,如双侧顶叶与前额叶等在数字加工中的地位与作用,以及不同脑区之间的关系进行了探讨,并对一个广泛运用的数字加工神经机制模型进行了简要评述。在此基础上,对数字加工的皮层定位问题进行了简要的总结。     

视觉工作记忆内容对视觉搜索的影响

采用记忆任务与视觉搜索任务相结合的范式,以二维对称图形为材料,探讨视觉工作记忆内容对视觉搜索的影响。结果发现：（1）不同视觉工作记忆内容条件下的反应时存在显著差异,无效信息条件下的反应时显著长于有效信息条件下的反应时。（2）不同搜索序列条件下反应时差异显著,复杂序列条件下的反应时显著长于简单序列条件。结果表明,视觉工作记忆中的信息内容影响视觉搜索效率,其变化趋势不受序列大小的影响,结果支持偏向竞争模型。     

视觉搜索相关理论研究的历史、现状与未来

近年来对视觉搜索的研究众多，其中由Treisman和她的同事最早提出的特征整合理论(FIT)在过去的30年中一直扮演着重要的角色，其间也有很多学者对此现象提出了不同的理论及模型。本文简单回顾了有关这一现象的历史并对其最新进展做了概要介绍，最后就这一现象的未来做了行为科学和认知神经科学方面的展望。     

视觉搜索有记忆参与

采用动态搜索任务,系统改变刺激项位置变换的速度,探讨视觉搜索是否有"记忆"参与.结果发现:(1)刺激项位置的变换速度较快时(120 ms/次、220 ms/次),动态搜索的搜索效率显著低于静态搜索;(2)刺激项位置的变换速度较慢时(420 ms/次),动态搜索的搜索效率与静态搜索无差异.该结果表明视觉搜索有"记忆"参与,返回抑制可能是视觉搜索中"记忆"的内在机制.     

Identifying when children with visual impairment share attention: A novel protocol and the impact of visual acuity

BackgroundIn Coordinated Joint Engagement (CJE), children acknowledge that they and their social partners are paying attention to the same object. The achievement of CJE, critical for healthy development, is at risk in infants with visual impairment (VI). Research on CJE in these children is limited because investigators use a child’s gaze switch between social partner and object to index CJE. Research is needed that identifies CJE in children with VI using behaviors that do not require normal vision and that explores the relationship between CJE and visual function. This study aimed to (a) develop a protocol for identifying CJE in children with VI, and (b) explore the relationship between CJE and infants’ visual acuity (VA) and contrast sensitivity (CS), measured with Preferential Looking (PL) techniques and Visual Evoked Potential (VEP).MethodsA protocol that included 9 indices of CJE that did not require normal vision was developed to code videos of 20 infants with VI (mean age =1 year, 6 months, 27 days) and their caregivers. The percentage of CJE episodes in which each index was observed was calculated. Inter-coder reliability was measured using Cohen’s Kappa. Linear regression analysis was used to examine the relationship between the infants’ visual function and CJE.ResultsInter-rater reliability between a first coder and each of two second coders were 0.98 and 0.90 for determining whether the child participated in CJE. The following indices were observed the most (in 43–62 % of CJE): child’s body orientation to caregiver, gaze switch between caregiver and object, and vocalization to caregiver. The only significant model included VA (measured with PL) as a single predictor and explained 26.8 % of the variance in CJE.ConclusionsThe novel protocol can be used to identify CJE in children with VI with good inter-coder reliability. The data suggest that children with lower VA exhibited less CJE.     

Precuing the Target Location in Visual Searching by a Chimpanzee (Pan troglodytes): Effects of Precue Validity

A chimpanzee ( Pan troglodytes ) performed a visual search task using a modified matching-to-sample procedure in which a sample stimulus was followed by the search display, which contained one stimulus identical to the sample (target) and several uniform stimuli different from the sample (distractors). On cued trials, while the subject was observing the sample, a white square (precue) appeared at the location where the target was to be presented (valid trials), or elsewhere (invalid trials). The validity of the precue (correspondence between the cued and the target locations) was changed from 0% to 100% across conditions. Cost-benefit analyses were performed on the difference between valid and noncued trials (benefit) and between invalid and noncued trials (cost). Under the high-validity conditions, the response times were shorter when the cued location corresponded to the target location than when the precue did not appear. When the cued location did not correspond to the target location, on the other hand, the subject took longer to select the target than on noncued trials. When the validity of the precue was relatively low, however, cost of the invalid trials disappeared, while benefit of the valid trials remained. These results confirmed the two-process (automatic and attentional) theory of priming in human information processing; the advance information had the same effects on a chimpanzee's visual search performance as on humans'.     

参照性交流双方学习过程与选择性注意的比较

研究以大学生为被试,采用参照性交流范式,设计虚拟学习材料并创设功能预测和维度选择任务,探查比较参照性交流双方学习过程与选择性注意特点。结果发现：与低分组比较,高分组从学习阶段2开始得分显著更高;且维度选择整体结果显著优于低分组,这主要表现在对无关维度的抑制水平显著更高。结果表明：参照性交流双方的学习过程表现出不平衡性;参照性交流双方的选择性注意整体水平表现出不平衡性,具体表现于选择性注意的集中性水平。     

进展性脑梗死的形成机制与防治策略

进展性脑梗死是临床上常见的一种缺血性脑卒中,其发病率高,致残率高,预后较差,严重危害患者的生命和健康,成为临床卒中治疗的一大难题。本文结合近年来的有关研究文献,就进展性脑梗死的临床分型、形成机制、可能的危险因素及其防治策略等方面的研究进展作一综合性介绍。     

Form-Specific Visual Priming in the Left and Right Hemispheres

Word fragment completion performance was examined for items that were presented in the same or different letter case at study and test. During the study phase words and nonwords were presented at central fixation, then during the test phase a divided visual field technique was used in which word fragments were presented briefly to the right hemisphere (left visual field) or the left hemisphere (right visual field). Previous research using the word stem completion task indicated that only the right hemisphere was sensitive to case changes in words from study to test. In contrast, the current results indicate that in the fragment completion task the priming effects for the test items presented to either hemisphere were greater when the fragments were in the same compared to different letter case at study and test. These results indicate that both hemispheres are capable of supporting form-specific visual implicit memory.     

Focal attention and the perception of pattern structure in extrafoveal vision

Several studies have shown that visual attention enhances the encoding of the positional relationships between pattern elements, i.e., the perception of pattern structure. This theoretical note discusses the possibility that the inferiority of extrafoveal vision in the perception of pattern structure results, at least partially, from less effective focal attention in the periphery. Hence, there may exist higher level differences between foveal and extrafoveal vision in information processing which cannot be explained by the spatial inhomogeneity of the retino-striate system.     

Conflict and Cognitive Control in the Brain

ABSTRACT— Recent research from cognitive psychology and cognitive neuroscience has suggested that the control mechanisms by which people are able to regulate task performance can be dissociated into evaluative and executive components. One process, implemented in the anterior cingulate cortex of the brain, monitors the amount of conflict that occurs during information processing; another process, implemented in the dorsolateral prefrontal cortex, is involved with maintaining the requirements of the task at hand and with biasing information processing in favor of appropriate responses. In the current article, we review this theory and some of the research that has supported it, including its implication for understanding cognitive disturbances in clinical disorders such as schizophrenia and obsessive-compulsive disorder. We conclude by addressing several interesting possibilities for future research.     

A Field Experiment Comparing Anchored and Unanchored Criteria Weights in the Analytic Hierarchy Process

This study reports the results of a field experiment comparing the predictive validity of two approaches to multicriteria assessments: the absolute measurement mode of AHP and the absolute measurement mode of linking pin AHP. The questioning procedures of the two differ only in that the former employs unanchored criteria weight assessments and the latter anchored criteria weight assessments. The decision task required insurance agents to respond to a mailed questionnaire in which they evaluated non-monetary incentives (contests) according to (1) the public recognition received from winning, (2) the criteria for winning and (3) the nature of the reward. There were four levels for each dimension. A between subjects design was used, with each subject receiving one of the two methods. In addition, all subjects divided 100 points among four contests and these hold-out assignments were employed as a validity check. Linking pin AHP was found to be superior to conventional AHP in this experiment, lending weight to the argument that the use of unanchored criteria weights is problematic. © 1997 by John Wiley & Sons, Ltd. J. Multi-Crit. Decis. Anal. 6 : 140–149 (1997) No. of Figures: 3. No. of Tables: 5. No. of References: 24.     

Progress in Reconciliation: Evidence from the Right and the Left

For a number of years now I have argued for a reconciliation of contemporary conceptions of justice. I have argued that a libertarian conception of justice with its ideal of liberty, a welfare liberal conception of justice with its ideal of fairness, a socialist conception of justice with its ideal of equality, a communitarian conception of justice with its ideal of the common good, and a feminist conception of justice with its ideal of androgyny can all be seen to support the same practical requirements, specifically the practical requirements that are usually associated with a welfare liberal conception of justice, namely, a right to welfare and a right to equal opportunity. Since most people endorse one or another of these conceptions of justice, to reach agreement in practice it should suffice to show them that all these conceptions support the same practical requirements of a right to welfare and a right to equal opportunity.