Is visual short-term memory object based? Rejection of the "strong-object" hypothesis

Is the capacity of visual short-term memory (VSTM) limited by the number of objects or by the number of features? VSTM for objects with either one feature or two color features was tested. Results show that capacity was limited primarily by the number of colors to be memorized, not by the number of objects. This result held up with variations in color saturation, blocked or mixed conditions, duration of memory image, and absence or presence of verbal load. However, conjoining features into objects improved VSTM capacity when size-orientation and color-orientation conjunctions were tested. Nevertheless, the number of features still mattered. When feature heterogeneity was controlled, VSTM for conjoined objects was worse than VSTM for objects made of single features. Our results support a weak-object hypothesis of VSTM capacity that suggests that VSTM is limited by both the number of objects and the feature composition of those objects.     

A simulation study of the degrees of freedom of movement in reaching and grasping

The question of independently controlled components in the act of reaching and grasping has attracted interest experimentally and theoretically. Data from 35 studies were recently found consistent with simulated kinematic finger and thumb trajectories optimised for minimum jerk. The present study closely reproduces those trajectories using a discrete-time model based on minimum acceleration. That model was further used to generate two-dimensional trajectories for finger and thumb to reach and grasp an elliptical object with varying position and/or orientation. Orthogonalisation of these four trajectories revealed one degree of freedom when direction of reach was constant and two degrees of freedom when direction of reach varied, irrespective of object distance and orientation. These simulations indicate that reach and grasp movements contain redundancy that is removable by formation of task-dependent synergies. As skilled movement can be planned and executed in a low dimension workspace, control of these independent components lessens central workload.     

Spatial context learning in visual search and change detection

Humans conduct visual search more efficiently when the same display is presented for a second time, showing learning of repeated spatial contexts. In this study, we investigate spatial context learning in two tasks: visual search and change detection. In both tasks, we ask whether subjects learn to associate the target with the entire spatial layout of a repeated display (configural learning) or with individual distractor locations (nonconfigural learning). We show that nonconfigural learning results from visual search tasks, but not from change detection tasks. Furthermore, a spatial layout acquired in visual search tasks does not enhance change detection on the same display, whereas a spatial layout acquired in change detection tasks moderately enhances visual search. We suggest that although spatial context learning occurs in multiple tasks, the content of learning is, in part, task specific.     

达米特论意义和真

达米特的反实在论意义理论在当代语言哲学中占据重要地位.本文主要分析了他对"意义"和"真"这两个概念的解释,指出他的意义理论完全是一种形式说明,或者说,是对意义理论本身的形式构造.同时,达米特反对用真值条件来解释意义,主要是根据他对"真"这个概念有着不同的理解:他把"真"看作我们在具体场合说出的句子的属性.达米特的思想受到了各方面的批评,他也在这种批评和反批评过程中不断完善自己的思想.     

What kind of memory supports visual marking?

In visual search tasks, if a set of items is presented for 1 s before another set of new items (containing the target) is added, search can be restricted to the new set. The process that eliminates old items from search is visual marking. This study investigates the kind of memory that distinguishes the old items from the new items during search. Using an accuracy paradigm in which perfect marking results in 100% accuracy and lack of marking results in near chance performance, the authors show that search can be restricted to new items not by visual short-term memory (VSTM) of old locations but by a limited capacity and slow-decaying VSTM of new locations and a high capacity and fast-decaying memory for asynchrony.     

Top-Down Attentional Guidance Based On Implicit Learning of Visual Covariation

The visual environment is extremely rich and complex, producing information overload for the visual system. But the environment also embodies structure in the form of redundancies and regularities that may serve to reduce complexity. How do perceivers internalize this complex informational structure? We present new evidence of visual learning that illustrates how observers learn how objects and events covary in the visual world. This information serves to guide visual processes such as object recognition and search. Our first experiment demonstrates that search and object recognition are facilitated by learned associations (covariation) between novel visual shapes. Our second experiment shows that regularities in dynamic visual environments can also be learned to guide search behavior. In both experiments, learning occurred incidentally and the memory representations were implicit. These experiments show how top-down visual knowledge, acquired through implicit learning, constrains what to expect and guides where to attend and look.     

卫生资源优化配置的伦理要求

卫生资源是稀缺资源,卫生资源只有优化配置,才能达到我们的医学目的。卫生资源的优化配置的以公平为优先,坚持公平和效率相结合的原则。就目前所存在的和我们的医学目的不相适应的卫生资源配置方式的现状和主要问题进行分析,并提出了相应的改进方法。     

Childhood abuse in Chinese patients with borderline personality disorder

This study examined (1) the relative prevalence of childhood abuse and other pathological childhood experiences in China reported by outpatients with borderline personality disorder (BPD), with other personality disorders, and without personality disorders; and, (2) whether the primary predictors of BPD in North America are associated with the development of BPD in China. The childhood experiences of 203 outpatients with BPD, 109 outpatients with other personality disorders, and 70 outpatients without Axis II diagnoses were assessed with the Chinese version of the Childhood Experience of Care and Abuse Questionnaire (CECA.Q). Patients with BPD reported significantly more physical, emotional, and sexual abuse than either comparison group. Four types of childhood experiences were significant predictors of BPD: maternal neglect, paternal antipathy, sexual abuse, and maternal physical abuse. The findings suggest that maternal physical abuse is as strong a predictor of BPD in China as sexual abuse, a finding not replicated in North America.     

论马克思主义的整体性(上)

近年来,随着 "马克思主义理论"被正式确立为国家一级学科,"马克思主义学院"在全国高等院校纷纷成立,国内马克思主义研究在表面上也呈现出一派热闹非凡的景象。于是马克思主义的整体性问题被提了出来。然而,与这种表面上热闹的景象形成鲜明对照的是,真正从心灵深处认同、信仰马克思主义的人并不很多。这种悖论式的现象不能不引起我们足够的重视。对于研究马克思主义的理论工作者而言,必须对眼前令人眼花缭乱的马克思主义 "热"进行 "冷"思考,就是说,必须认真地、郑重地提出并弄清这样一个问题: 马克思主义就其本义而言,是站在大众立场、为大众立言、为     

基于概念辨析的类比推理研究的新视角

该研究从概念的辨析上着手,不仅可以在相似的多个概念上理清各自的异同,更重要的是分析得出,作为科学发现和创造性思维的核心———类比推理(狭义类比推理),它有着不同于一般思维活动中的类比推理(广义类比推理)的特点。在此基础之上,才能更好地揭示其发生的规律,以利于更进一步的实证研究。