Perceiving stimulus displacements across saccades

The visual world appears stable despite frequent retinal image movements caused by saccades. Many theories of visual stability assume that extraretinal eye position information is used to spatially adjust perceived locations across saccades, whereas others have proposed that visual stability depends upon coding of the relative positions of objects. McConkie and Currie (1996) proposed a refined combination of these views (called the Saccade Target Object Theory) in which the perception of stability across saccades relies on a local evaluation process centred on the saccade target object rather than on a remapping of the entire scene, with some contribution from memory for the relative positions of objects as well. Three experiments investigated the saccade target object theory, along with an alternative hypothesis that proposes that multiple objects are updated across saccades, but with variable resolution, with the saccade target object (by virtue of being the focus of attention before the saccade and residing near the fovea after the saccade) having priority in the perception of displacement. Although support was found for the saccade target object theory in Experiment 1, the results of Experiments 2 and 3 found that multiple objects are updated across saccades and that their positions are evaluated to determine perceived stability. There is an advantage for detecting displacements of the saccade target, most likely because of visual acuity or attentional focus being better near the fovea, but it is not the saccade target alone that determines the perception of stability and of displacements across saccades. Rather, multiple sources of information appear to contribute.     

The effect of spatial organization of targets and distractors on the capacity to selectively memorize objects in visual short-term memory

We conducted a series of experiments to explore how the spatial configuration of objects influences the selection and the processing of these objects in a visual short-term memory task. We designed a new experiment in which participants had to memorize 4 targets presented among 4 distractors. Targets were cued during the presentation of distractor objects. Their locations varied according to 4 spatial configurations. From the first to the last configuration, the distance between targets’ locations was progressively increased. The results revealed a high capacity to select and memorize targets embedded among distractors even when targets were extremely distant from each other. This capacity is discussed in relation to the unitary conception of attention, models of split attention, and the competitive interaction model. Finally, we propose that the spatial dispersion of objects has different effects on attentional allocation and processing stages. Thus, when targets are extremely distant from each other, attentional allocation becomes more difficult while processing becomes easier. This finding implicates that these 2 aspects of attention need to be more clearly distinguished in future research.     

边界促进空间导航的认知神经机制

边界是指在人的视野中占据较大比例,且具有立体拓展平面的障碍物,对于人类和动物的空间导航行为具有极大的促进作用。认知发展研究发现儿童早期(1岁半～2岁)通过加工边界的空间几何结构实现物体定位,并且随着年龄的发展逐渐学会利用边界的高度信息(3.1岁～4.7岁)、长度信息(4～5岁)、视觉阻碍性信息(5岁)等完成空间导航。基于这些认知过程,神经影像学研究主要以成人为研究被试,发现大脑中的内侧颞叶和顶叶脑区在边界加工中有着不同功能作用。具体而言,边界的空间几何结构及构成要素(高度、长度和角度)体位置的学习和提取则由海马负责。但是,仍存在一些研究问题值得未来深入S探c讨i。e第n一c,e拓展深化边界促进与后顶叶之间的功能交互。第三,密切关注大脑对场地边界与场地中心编码的心理或神经表征的区别和联系。第四,重点考察阿尔兹海默症有关基因易感人群在基于边界导航的行为受损情况。最后,延伸探讨边界在长时记忆、时间知觉、视觉空间、社交网络等领域的影响机制。     

康熙年间疫灾流行的特征与应对

康熙年间疫灾频度为96.72%,形成持续上升(1662年~1680年)、持续下降(1681年~1687年)、波动上升(1688年~1708年) 和再次回落(1709年~1722年)4个阶段,并以夏、秋季为疫灾流行的主要时节。康熙年间疫灾的空间分布呈现内地多于边疆、南方多于北方、东部多于中西部的特征,其中江苏是疫灾流行最严重的省份。康熙年间疫灾流行的应对方式整体上停留于体现康熙帝意志的中央政令,官方延医赠药、施棺瘗尸、刊刻医书,民间逃疫避疫、封建迷信等传统应对阶段,但由于帝王的格外关注,特别是在特定疫病如天花、疟疾等的应对上也出现一些新变化。

     

小学儿童在不同刺激材料中的左右空间方位传递性推理能力及策略分析

采用定性和定量相结合的研究方法,从图形刺激材料和文字刺激材料入手,探查了7岁、9岁、11岁儿童的一维空间方位传递性推理能力的发展水平及其认知策略。主要研究结果表明:(1)小学儿童的一维空间方位传递性推理能力从7岁到9岁,从9岁到11岁都有显著性提高。7岁儿童处于能力的初步形成期,9岁儿童是能力的提高和发展期,11岁儿童已基本具有了一维空间方位单模型条件下的传递性推理能力;(2)小学儿童在图形刺激材料条件下的推理成绩显著优于文字刺激材料条件下的推理成绩;(3)前提数量的增加没有对小学儿童的推理造成显著性影响;(4)随着儿童年龄的增长,模型建构策略的使用者越来越多,但在图形刺激材料和文字刺激材料下,儿童解决问题的策略有所不同。在图形刺激材料下,大部分7岁和9岁的儿童采用知觉策略,11岁儿童中只有少部分人使用这一策略。在文字刺激材料下,模型建构策略是儿童推理的主要策略。少部分7岁儿童使用模型建构策略,大部分9岁儿童和绝大部分11岁儿童使用模型建构策略来解决问题。     

客体相似性对不同认知方式个体视觉工作记忆表征的影响

采用整体检测的变化察觉范式,探讨客体的相似性对客体—空间型认知方式个体视觉工作记忆表征的影响。行为结果显示,在不相似客体的视觉工作记忆表征任务中,客体型者在长延时条件的成绩优于空间型者,而在相似客体的视觉工作记忆表征任务中,两者无差异;ERP结果显示,在不相似客体视觉工作记忆表征任务中,与客体型者相比,空间型者在大脑皮层诱发出更大的负SP。以上结果表明,客体型者比空间型者对不相似客体视觉工作记忆加工具有优势,其潜在机制可能在于,客体型者对不相似客体视觉工作记忆表征时的神经活动效能更高。     

Time‐of‐day variation of visuo‐spatial attention

Time‐of‐day variation of visuo‐spatial attention in relation to body temperature and subjective arousal was assessed. At five different times of day, alertness, covert, and overt orienting of attention were assessed in fifteen healthy subjects. Based on previous studies reporting a tight coupling of alerting and orienting the present study investigates potential attentional asymmetries induced by diurnal variations of arousal. Both covert and overt orienting of attention improved in the course of the day. However, no asymmetries between left and right visual hemifields could be detected. Covert orienting additionally covaried with body temperature, indicating a quite close relation between the attentional arousal and orienting system. Conversely, overt orienting only improved due to repeated testing but did not correlate with body temperature suggesting a partial independence of both modes of attentional orienting. It can be assumed that due to limited diurnal variations of arousal in the participants and practice effects caused by repeated testing, no attentional asymmetries could be provoked.     

语言线索对空间关系表征的影响及其机制

语言的获得会对空间认知产生深刻的影响。关于语言与空间认知,近些年来,不仅有大量的相关研究发现语言能力跟空间认知能力之间存在着密切的关联,还出现了实验研究,来试图直接揭示语言对空间关系表征的影响。研究发现,在一系列涉及不同空间关系的任务中,相较于非语言线索,语言线索提示的效果明显更好。在此基础上,从语言编码的特点和加工过程等方面进一步分析语言的作用机制,发现在空间表征中语言主要起到了选择和整合的作用,语言的作用过程是即时性的。建议未来研究在空间任务和语言表述形式上有更多的变式,从而更全面地来揭示语言的作用。