Mapping the time course of the positive classification advantage: An ERP study

The aim of the present study was to investigate the time course of the positive advantage in the expression classification of faces by recording event-related potentials (ERPs). Although neutral faces were classified more quickly than either happy or sad faces, a significant positive classification advantage (PCA)—that is, faster classification for happy than for sad faces—was found. For ERP data, as compared with sad faces, happy faces elicited a smaller N170 and a larger posterior N2 component. The P3 was modulated by facial expressions with higher amplitudes and shorter latencies for both happy and neutral stimuli than for sad stimuli, and the reaction times were significantly correlated with the amplitude and latency of the P3. Overall, these data showed robust PCA in expression classification, starting when the stimulus has been recognized as a face revealed by the N170 component.     

Dynamic orientation cues decrease the viewpoint cost of mental rotation

Mental rotation, as a covert simulation of motor rotation, could benefit from spatial updating of object representations. We are interested in what kind of visual cue could trigger spatial updating. Three experiments were conducted to examine the effect of dynamic and static orientation cues on mental rotation, using a sequential matching task with three-dimensional novel objects presented in different views. Experiment 1 showed that a rotating orientation cue with constant speed reduced viewpoint costs in mental rotation. Experiment 2 extended this effect with a varied-speed rotating orientation cue. However, no such benefit was observed with a static orientation cue in Experiment 3. These findings indicated that a visually continuous orientation cue is sufficient to elicit spatial updating in mental rotation. Furthermore, there may be differences in the underlying mechanisms of spatial updating on the basis of constant-speed rotating cues and varied-speed rotating cues.     

Effects of divided attention and social categorization on the own-race bias in face recognition

Perceivers remember own-race faces more accurately than other-race faces (i.e., Own-Race Bias). In the current experiments, we manipulated participants' attentional resources and social group membership to explore their influence on own and other-race face recognition memory. In Experiment 1, Chinese participants viewed own-race and Caucasian faces, and between-subjects we manipulated whether participants attention was divided during face encoding. We found that divided attention eliminated the Own-Race Bias in memory due to a reduction of memory accuracy for own-race faces, implicating that attention allocation plays a role in creating the bias. In Experiment 2, Chinese participants completed an ostensible personality test. Some participants were informed that their personality traits were most commonly found in Caucasian (i.e., other-race) individuals, resulting in these participants sharing a group membership with other-race targets. In contrast, other participants were not told anything about the personality test, resulting in the default own-race group membership. The participants encoded the faces for a subsequent recognition memory test either with or without performing a concurrent arithmetic distracting task. Results showed that other-race group membership and reducing attention during encoding independently eliminated the typical Own-Race Bias in face memory. The implications of these findings on perceptual-expertise and social-categorization models are discussed.     

Static items are automatically prioritized in a dynamic environment

Everyday experience provides us with the intuition that dynamic events guide or capture attention—something which has been confirmed in experimental studies. Recently, we showed that there are limitations to the extent to which dynamic items attract attention. In a visual search task where all items, except one, were dynamic, the dynamic items could be ignored and the static item could be efficiently detected. In the present study we investigated whether attention is automatically drawn to the static item. Three visual search experiments, in which the target and the static object were uncorrelated, revealed that the static item was nevertheless prioritized. This result is at odds with some of the current theories on attentional capture, including the “new object” hypothesis. The current study suggests that differences in dynamics, rather than dynamic features per se, determine where attention is allocated.     

Waldo reveals cultural differences in return fixations

ABSTRACT

Humans routinely perform visual search towards targets to adapt to the environment. These sequences of ballistic eye movements are shaped by a combination of top–down and bottom–up factors. Recent research documented that human observers display cultural-specific fixation patterns in a range of visual processing tasks. In particular, eye movement strategies extracting information from faces clearly differs between Western Caucasian (WC) and East Asian (EA) observers. However, whether such cultural differences are also present for visual scene processing remains debated. To this aim, we recorded the eye movements of WC and EA observers while they were solving visual search problems parametrically varying in difficulty: Where’s Waldo. Both groups had a comparable familiarity with the Waldo books reaching a comparable level of accuracy in target detection. Both cultural groups also showed a comparable temporal effect on inhibition of return, with longer fixation durations when saccades were performed to a return location compared to other locations. Westerners, however, located Waldo faster than Easterners. Interestingly, this modulation of speed was likely related to differences occurring on the low-level mechanisms of spatial inhibition of return, with EA observers returning more often to previously visited locations than the WC observers. This suboptimal eye movement strategy in the Easterners might be engendered by their cultural perceptual bias consisting in? a greater use of extra-foveal information. Overall, our data point towards the existence of a subtle, but significant difference in the processing of visual scenes across observers from different cultures during active visual search.     

生存加工的编码和提取双重优势效应:ERP证据

生存加工比控制条件有更好的记忆表现,产生稳定的记忆优势,这就是记忆生存优势.已有研究多采用行为学实验验证了此现象的存在,但没有确定该优势发生在记忆的何种阶段.本研究采用ERP技术和“间接学习-再认”实验范式,比较被试在生存情境、迁徙情境和愉悦判断中对词汇编码和提取过程的记忆加工,结果发现:在500-700ms时间段,生存情境的相继记忆效应显著大于迁徙情境和愉悦判断:在400-600ms时间段,生存情境的新旧效应显著大于迁徙情境和愉悦判断.表明生存加工具有编码和提取双重优势.     

流动儿童疏离感的特点及其与应对方式、学校态度的关系

采取整群抽样的方法,对成都及重庆两地591名流动儿童和272名城市儿童进行问卷调查,考察流动儿童疏离感的特点及其与应对方式和学校态度的关系。结果发现:(1)流动儿童疏离感各维度显著高于城市儿童;流动初中生的疏离感显著高于流动小学生,且男生的疏离感显著高于女生;(2)流动儿童疏离感的三个维度之间存在显著差异,其中社会疏离感最高,其次是环境疏离感,人际疏离感最低;(3)流动儿童疏离感对学校喜欢有显著的负向影响,而对学校回避有显著的正向影响;应对方式在流动儿童疏离感对学校态度的影响中起着部分中介作用。     

概称句词项逻辑的树图判定算法

概称句的形式刻画研究始于人工智能。从条件蕴涵引入开始,到建立概称句词项逻辑的形式系统GAG和Gaa,关于概称句这一系列的研究主要是围绕概称句自身性质的探讨,以试图对于概称句推理给出更合理的形式刻画,而没有同时兼顾计算机应用方面的考虑。回归问题的初始,关于概称句的概念理论是否还可以用于计算机科学领域,是这一研究路线所面临的问题。首先要解决的问题是,根据GAG和Gaa模型,公式的可满足性是否有能行的判定方法。对此本文给出了基于GAG语义的树图判定算法,包括相应的可靠性,完备性等证明。     

现代生物技术前沿与创新药物研究的思考

生物技术是当今世界发展最快,潜力最大和影响最深远的高新技术之一。极大地推动着创新药物研究的发展,在基因组学,蛋白质组学,生物信息学和生物芯片等几个生物技术前沿大大拓展了创新药物研究的方法和理论,使创新药物研究具有前所未有的广阔的用武之地。     

创造性的生理研究新进展

创造性的生理基础很复杂。关于创造性生理基础的研究集中在大脑皮质激活与脑半球不对称两个方面。研究发现,大脑皮质激活状态对创造性有影响,低水平的皮质激活,特别是低水平的前额叶激活,较有利于创造性．研究还发现,创造性和左右半球不对称活动有关,处于创造状态时,右半球相对要比左半球激活程度更高。