A quasi-nonmetric method for multidimensional scaling VIA an extended euclidean model

An Extended Two-Way Euclidean Multidimensional Scaling (MDS) model which assumes both common and specific dimensions is described and contrasted with the standard (Two-Way) MDS model. In this Extended Two-Way Euclidean model then stimuli (or other objects) are assumed to be characterized by coordinates onR common dimensions. In addition each stimulus is assumed to have a dimension (or dimensions) specific to it alone. The overall distance between objecti and objectj then is defined as the square root of the ordinary squared Euclidean distance plus terms denoting the specificity of each object. The specificity,s _j , can be thought of as the sum of squares of coordinates on those dimensions specific to objecti, all of which have nonzero coordinatesonly for objecti. (In practice, we may think of there being just one such specific dimension for each object, as this situation is mathematically indistinguishable from the case in which there are more than one.)We further assume that _ij =F(d _ij ) +e _ij where _ij is the proximity value (e.g., similarity or dissimilarity) of objectsi andj,d _ij is the extended Euclidean distance defined above, whilee _ij is an error term assumed i.i.d.N(0, ²).F is assumed either a linear function (in the metric case) or a monotone spline of specified form (in the quasi-nonmetric case). A numerical procedure alternating a modified Newton-Raphson algorithm with an algorithm for fitting an optimal monotone spline (or linear function) is used to secure maximum likelihood estimates of the paramstatistics) can be used to test hypotheses about the number of common dimensions, and/or the existence of specific (in addition toR common) dimensions.This approach is illustrated with applications to both artificial data and real data on judged similarity of nations.     

Understanding environments: The key to improving social processes and program outcomes

The contributions to this Special Issue illustrate research on several important types of environmental units, including psychiatric and substance abuse treatment programs, neighborhood block groups, and entire communities. They also exemplify alternative methodologies, such as assessing environments by relying on participants' appraisals, external observers' ratings, historical archives, and direct observation. I draw on these contributions and some of my own work to discuss four recurrent issues: (a) how to conceptualize environmental domains and dimensions; (b) how to understand environmental dynamics, that is, the interplay of environmental factors both within one setting and across settings; (c) how to comprehend the processes that link environmental factors to outcomes, especially with respect to the power and evanescence of environmental influence; and (d) how to use information about environments to monitor and improve them. Increased knowledge in these four areas is essential to help fulfill a major aim of community psychology: to understand social processes and improve intervention program outcomes.     

Science, Values and the Human Dimensions

The presented paper substantiates the principle that values are an immanent component of science and any rational cognitive activity. This principle belongs to the European cultural tradition starting from the book of Genesis of the Old Testament, the values of certainty in the antique Greek philosophy and Francis Bacon's coincidence of knowledge and power. Values in science form complicated structures inconnection with different types of knowledge including “the knowledge that”, empirical evidence, various types of generalizations or rules, methods, directions, algorithms, “the knowledge how”, “the knowledge why” or other types of knowledge. Since the assignments of different types of values are the products of a decision-making, it is useful to distinguish many types of decision-making, especially semantic decision-making, information decision-making and decision-making with distinctly pragmatic dimensions. The values assignable to scientific activities and their results also include their social recognition, respect and prestige granted to knowledge and bearers of knowledge by society and social groups or communities. Knowledge generation and the rational and justified application of the achieved and acceptable impacts are also connected with decision-making procedures, values and criteria of social acceptance. This revised version was published online in August 2006 with corrections to the Cover Date.     

Reasoning with Factors

The paper proposes an analysis and a formalisation of factor-based reasoning. After examining the relevance of factors in legal reasoning, binary and scalable factors (dimensions) are distinguished and the relations between them are discussed. An account of a fortiori reasoning with both types of factors is developed. This article reports ideas which are discussed and developed in Sartor (2005). We refer to the latter work for the theoretical framework in which our analysis of factors is embedded.     

A note on the equivalence of the graded response model and the sequential model

This paper concerns items that consist of several item steps to be responded to sequentially. The item scoreX is defined as the number of correct responses until the first failure. Samejima's graded response model states that each steph=1,...,m is characterized by a parameterb _h , and, for a subject with ability, Pr(Xh; )=F(–b _h ). Tutz's general sequential model associates with each step a parameterdh, and it states that Pr(Xh;)= _r ^=1h G(–d _r ). Tutz's (1991, 1997) conjectures that the models are equivalent if and only ifF(x)=G(x) is an extreme value distribution. This paper presents a proof for this conjecture.     

拓展后的GGUM在LOT-R中的适用性分析

该研究对拓广等级展开模型（GGUM）进行了拓展,取消GGUM中关于主观反应类别阈限对称的假设,并将拓展之后的新模型和GGUM同时用于生活取向测验修订版（LOT-R）的被试反应数据分析,采用新编的单项目、两项目对和三项目组χ2/df计算程序计算和比较新模型和GGUM在该测验数据上的拟合差异。结果显示,新编程序与Stark等人开发的MODFIT程序具有同样的有效性,新模型在这些指标上的值显著小于GGUM,并且均小于3,表明新模型较GGUM更适合于分析LOT-R的反应数据,说明新模型更适用于分析具有多个评定等级的人格测验数据。根据以上结果,该研究认为,未来人格测验的数据分析应该使用没有对主观反应类别阈限进行对称限定的新拓展的模型更合理。     

The retrieval of self-defining memories is associated with the activation of specific working selves

This article presents two studies that investigated the impact of the retrieval of self-defining memories on individuals' sense of self. Participants recalled positive and/or negative self-defining memories, rated memory characteristics and completed measures focusing on different self-aspects. Study 1 found that participants reported higher state self-esteem after recalling a positive memory than after recalling a negative one. They also reported lower negative self-consistency and higher state self-concept clarity and positive self-consistency, but this result became non-significant after controlling for state self-esteem. Study 2 found that participants reported higher state self-esteem, a marginally higher proportion of recreation/exploration, goals and a marginally lower proportion of achievement goals after recalling a positive memory than after recalling a negative one. They also reported a higher proportion of self-cognitions referring to emotional states after recalling memories from which they had not abstracted meaning than after recalling memories from which they had done this. These findings suggest that the retrieval of vivid, emotional and highly self-relevant memories may be accompanied by the activation of specific self-representations or working selves. They also suggest that the experience of memory-related intrusive images may temporarily influence individuals' sense of self. The implications of these findings for clinical practice are discussed.     

Adaptive and Maladaptive Perfectionism,Adult Attachment,and Big Five Personality Traits

The author examined the role of anxiety and avoidance dimensions of attachment and Big Five personality traits in adaptive and maladaptive dimensions of perfectionism among 604 (377 male, 227 female) Turkish university students. The results of 2 separate multiple regression analyses yielded that adaptive perfectionism was significantly predicted by conscientiousness, openness, and extraversion. Maladaptive perfectionism was significantly predicted by the neuroticism, anxiety, and avoidance dimensions of attachment. The authors discuss the implications, limitations, and future directions for research.     

Latent trait models and dichotomization of graded responses

This paper discusses thecompatibility of the polychotomous Rasch model with dichotomization of the response continuum. It is argued that in the case of graded responses, the response categories presented to the subject are essentially an arbitrary polychotomization of the response continuum, ranging for example from total rejection or disagreement to total acceptance or agreement of an item or statement. Because of this arbitrariness, the measurement outcome should be independent of the specific polychotomization applied, for example, presenting a specific multicategory response format should not affect the measurement outcome. When such is the case, the original polychotomous model is called compatible with dichotomization.A distinction is made between polychotomization or dichotomization before the fact, that is, in constructing the response format, and polycho- or dichotomization after the fact, for example in dichotomizing existing graded response data.It is shown that, at least in case of dichotomization after-the-fact, the polychotomous Rasch model is not compatible with dichotomization, unless a rather special condition of the model parameters is met. Insofar as it may be argued that dichotomization before the fact is not essentially different from dichotomization after the fact, the value of the unidimensional polychotomous Rasch model is consequently questionable. The impact of our conclusion on related models is also discussed.