Local spatial distortion caused by simple geometrical figures

Dynamic distortion of the visual field has been shown to affect perceptual judgment of visual dimensions such as size, length, and distance. Here, we report four experiments demonstrating that the different aspects of a triangle differently influence judgments of distance. Specifically, when the base of the triangle faces the centre of the display, participants consistently underestimate and overestimate the distance of a small dot from the unmarked centre of the display relative to conditions in which the vertex of the triangle faces the centre. When the dot is close to the figure, the distance of the dot to the centre is underestimated. Conversely, when the dot is close to the figure, the distance to the centre is overestimated. The effect is replicated when the internal distances are equalized and when ellipses are used instead of triangles. These results support a ripple model of spatial distortion in which local curvature acts to attract or repel objects. In conclusion, we suggest some implications of our findings for theories of perceptual organization.     

The assessment of knowledge and learning in competence spaces: The gain–loss model for dependent skills

The gain–loss model (GaLoM) is a formal model for assessing knowledge and learning. In its original formulation, the GaLoM assumes independence among the skills. Such an assumption is not reasonable in several domains, in which some preliminary knowledge is the foundation for other knowledge. This paper presents an extension of the GaLoM to the case in which the skills are not independent, and the dependence relation among them is described by a well‐graded competence space. The probability of mastering skill s at the pretest is conditional on the presence of all skills on which s depends. The probabilities of gaining or losing skill s when moving from pretest to posttest are conditional on the mastery of s at the pretest, and on the presence at the posttest of all skills on which s depends. Two formulations of the model are presented, in which the learning path is allowed to change from pretest to posttest or not. A simulation study shows that models based on the true competence space obtain a better fit than models based on false competence spaces, and are also characterized by a higher assessment accuracy. An empirical application shows that models based on pedagogically sound assumptions about the dependencies among the skills obtain a better fit than models assuming independence among the skills.     

三维空间中不同视野深度位置上的返回抑制

通过虚拟现实构建虚拟三维场景,将二维平面视觉空间返回抑制范式应用到三维空间,通过两个实验操纵了目标深度、线索有效性以及视野位置三个变量,考察注意在三维空间不同视野深度位置上进行定向/重定向产生的返回抑制效应。结果发现,(1)二次线索化位于固定的中央视野时,不论目标出现在近处空间还是出现在远处空间,外周视野条件下的返回抑制大于中央视野条件下的返回抑制;(2)二次线索化位于非固定的中央视野时,近处空间和远处空间的返回抑制存在分离,表现为当目标出现在远处空间时,外周视野条件下的返回抑制效应减小。研究表明,三维空间中外周视野深度位置上的返回抑制与中央视野深度位置上的返回抑制存在差异。     

Somalis as Samaritans: A Glimpse into Christian–Muslim Relations in Eastern Africa from the Perspective of Evangelical Kenyan Christians

Long considered – perhaps naïvely – a relative oasis of Christian–Muslim calm, Kenya is seeing increased tension and conflict, mainly exacerbated by al-Shabaab militants, Kenyan military and Christian mobs. Concomitantly, the media and popular sentiment often vilify Somalis. This goes back to government agitprop during the ‘Shifta War’ of the 1960s. Among evangelical Christians, however, attitudes towards Somalis can prove more ambivalent. Drawing on interviews conducted with both Kenyan evangelical Christians and Somali Muslims, this article seeks to examine the theological shift among Kenyan evangelicals wherein they have re-cast Somalis as Samaritans and in doing so have made their primary approach to this conflict one of evangelization, not open hostility. This shift is due to a confluence of factors including community context, economic pragmatism and religious motivations, and the focus on evangelism does not necessarily preclude peace-building. What this article aims to present is a glimpse into the outlook of Kenyan evangelicals towards Somalis, particular Somali Muslims, and discuss these attitudes in the nexus of factors mentioned above. The article will reveal how, by re-casting the Somali ‘villain’ as Samaritan, some Kenyan evangelicals maintain boundaries and foster new identities in Eastern Africa for the sake of a longed-for peace.     

Visualizing homelessness: a study in photography and estrangement

This article reports a qualitative study of how homeless people visualize their life in hostels and on the streets of London. Using a photo‐production technique, the research enabled participants to show their situation as well as to tell about their experiences. Participants were given cameras and asked to take photographs typical of their day as homeless people, this material being the subject of a subsequent interview. This provided both visual and text data that were analysed together so as to establish different engagements of the participants with the city and with domiciled people. Presenting the material from six of the participants, these different engagements are described with reference to issues of estrangement, exclusion and visualization employed as explanatory concepts. The article identifies and compares the different ways in which homeless people attempt not only to survive but also to [make their home] in the city. Copyright © 2005 John Wiley & Sons, Ltd.     

Traumatic effects of political repression in Chile: A clinical experience1

The author examines psychic trauma resulting from human rights violations in Chile. Starting from trauma theories developed by authors such as Ferenczi, Winnicott and Stolorow, she posits the relevance of the subject's emotionally signifi cant environment in the production of the traumatic experience. She describes the characteristics of the therapeutic process on the basis of a clinical case. She emphasizes the need to recognize the damage that may be produced within the reliable link between patient and analyst, pointing out the risk of retraumatization if analysts distance themselves and apply ‘technique’ rigorously, leaving out their own subjective assessments. Therapists must maintain their focus on the conjunction of the patient's intersubjective context and inner psychic world both when exploring the origin of the trauma and when insight is produced. The author posits repetition in the transference as an attempt at reparation, at fi nding the expected response from the analyst that will help patients assemble the fragments of their history and achieve, as Winnicott would put it, a feeling of continuity in the experience of being.     

Social dynamics in the preschool

In this paper, we consider how concepts from dynamic systems (such as attractors, repellors, and self-organization) can be applied to the study of young children’s peer relationships. We also consider how these concepts can be used to explore basic issues involving early peer processes. We use the dynamical systems approach called state space grid (SSG) analysis and consider how it can be expanded beyond the study of dyads to the study of larger social groups and networks. In particular, we explore the role of homophily—that is, behavioral and sex similarity—as factors in the self-organization of young children’s social groups. A dynamic systems approach allows for consideration of peer processes difficult to assess using more traditional approaches.     

A formal framework for characterizing querying algorithms

Algorithmic procedures have been devised for constructing a knowledge space by querying experts. The queries submitted to the expert consist of assertions that are to be accepted or rejected. The present paper provides a characterization of the algorithms that may be used to draw inferences from previously collected answers. It is based on the notion of a closure on the set of all assertions, and its extension to a set containing for each assertion a positive and a negative instance, representing acceptance and rejection, respectively. The developed characterization emphasizes the significance of the well-known QUERY and PS-QUERY procedures. Potential applications of the presented results in contexts other than knowledge space theory are pointed out.     

The influence of perceived prison crowding on male inmates' perception of aggressive events

This study examines whether, in a male prison, the subjective experience of crowding increases the likelihood that events are perceived as aggressive in nature, and whether the protagonists involved are viewed as more hostile, malevolent, and aggressive. In addition, this paper also examines the possible mediating effects of stress, arousal, and psychological well‐being on two hypothesised relationships. First, these mediating factors are examined for the link between individuals' personal space preferences and their perceived level of crowding. Second, these factors are examined for the link between perceived crowding and interpretations of an aggressive event. Such associations may help to explain why crowding and aggression are linked within a social interactionist perspective. The results confirmed previous findings that crowding is linked to increases in arousal and stress, and a reduction in psychological well‐being. This study also found, however, that those inmates who experienced crowding were also more likely to interpret behaviour as aggressive and violent. This relationship was not mediated by arousal, stress, or psychological well‐being. However, these factors were found to partially operate in the relationship between personal space preferences and the experience of subjective crowding. The implications of this study for social interactionist explanations of the link between crowding and prison violence are offered. Aggr. Behav. 30:273–283, 2004. © 2004 Wiley‐Liss, Inc.     

情绪、边框影响决策认知过程的实验研究

借用问题空间,通过实验探讨情绪、边框对决策认知过程的影响,以进一步考察边框效应的本质特点。结果如下：情绪、边框均独立对决策认知过程产生影响;积极、消极信息导致不同的加工方式;积极信息既利于节省认知资源,又利于作出符合当前环境的决策。