A class of multidimensional IRT models for testing unidimensionality and clustering items

We illustrate a class of multidimensional item response theory models in which the items are allowed to have different discriminating power and the latent traits are represented through a vector having a discrete distribution. We also show how the hypothesis of unidimensionality may be tested against a specific bidimensional alternative by using a likelihood ratio statistic between two nested models in this class. For this aim, we also derive an asymptotically equivalent Wald test statistic which is faster to compute. Moreover, we propose a hierarchical clustering algorithm which can be used, when the dimensionality of the latent structure is completely unknown, for dividing items into groups referred to different latent traits. The approach is illustrated through a simulation study and an application to a dataset collected within the National Assessment of Educational Progress, 1996. The author would like to thank the Editor, an Associate Editor and three anonymous referees for stimulating comments. I also thank L. Scaccia, F. Pennoni and M. Lupparelli for having done part of the simulations.     

A Unified Nonparametric IRT Model for <Emphasis Type="Italic">d</Emphasis>-Dimensional Psychological Test Data (<Emphasis Type="Italic">d</Emphasis>-ISOP)

The (univariate) isotonic psychometric (ISOP) model (Scheiblechner, 1995) is a nonparametric IRT model for dichotomous and polytomous (rating scale) psychological test data. A weak subject independence axiom W1 postulates that the subjects are ordered in the same way except for ties (i.e., similarly or isotonically) by all items of a psychological test. A weak item independence axiom W2 postulates that the order of the items is similar for all subjects. Local independence (LI or W3) is assumed in all models. With these axioms, sample-free unidimensional ordinal measurements of items and subjects become feasible. A cancellation axiom (Co) gives, as a result, the additive isotonic psychometric (ADISOP) model and interval scales for subjects and items, and an independence axiom (W4) gives the completely additive isotonic psychometric (CADISOP) model with an interval scale for the response variable (Scheiblechner, 1999). The d-ISOP, d-ADISOP, and d-CADISOP models are generalizations to d-dimensional dependent variables (e.g., speed and accuracy of response). The author would like to thank an Associate Editor and two anonymous referees and also Professor H.H. Schulze for their very valuable suggestions and corrections.     

Effects of unilateral hippocampus-amygdala-partial temporal lobe resection on auditory EEG/MEG responses: a case study

Auditory orienting and discrimination were studied with combined multi-channel EEG and MEG recordings in a patient with unilateral amygdala-hippocampus-partial temporal lobe resection of the right hemisphere. The results revealed abnormalities of habituation in alerting- and orienting-related responses, and discrimination-related responses, elicited by auditory stimulation contralateral to the resected cerebral hemisphere. These results give support to the notions about the role of the amygdala and hippocampus in alerting and orienting, respectively, and of the temporal cortex in auditory discrimination.     

Parsing Pregroup Grammars and Lambek Calculus Using Partial Composition

The paper presents a way to transform pregroup grammars into contextfree grammars using functional composition. The same technique can also be used for the proof-nets of multiplicative cyclic linear logic and for Lambek calculus allowing empty premises.     

Work Barriers in the Context of Pathways to the Employment of Welfare-to-Work Clients

The ability of welfare-to-work clients to leave the welfare rolls and stay in the labor force is often limited by the work barriers they face. Using a sample of 1,404 female welfare-to-work clients we first examined the structure of work barriers and then tested their contribution to current work status in the context of a structural equation model that incorporated other central pathways to employment. Whereas work barriers included diverse factors ranging from lack of transportation to low quality jobs, they were shown to constitute a uni-dimensional construct. Furthermore, work barriers had a net adverse effect on employment outcomes, controlling for job search self-efficacy and employment intention. We conclude with discussion of implications for the development of welfare-to-work programs and interventions that target low-income women.     

Community types and mental health: a multilevel study of local environmental stress and coping

Research has found that neighborhood structural characteristics can influence residents' mental health. Few studies, however, have explored the proximal reasons behind such influences. This study investigates how different types of communities, in terms of environmental stressors (social and physical disorder and fear of crime) and social resources (informal ties and formal organizational participation), affect well-being, depression, and anxiety in adult residents. Data are from a survey of 412 residents nested in 50 street blocks. Block stressors and resources were cluster analyzed to identify six block types. After controlling for several individual- and block-level characteristics, results from multilevel models suggest that in communities facing relatively few stressors, higher levels of formal participation are associated with better mental health. Because high levels of formal participation were not found in communities with higher levels of stressors, the impact of participation in such contexts could not be examined. However, results suggest that in communities where stressors are more common, isolation from neighbors may have a protective effect on mental health.     

The Buss–Perry Aggression Questionnaire: Some unfinished business

This article gauges the extent to which items and sum scores of the Buss–Perry Aggression Questionnaire (BPAQ) are contaminated with social desirability response set (SDR), and the extent to which that contamination results in biased findings. Special validity coefficients are introduced for that purpose. Although the SDR confound was quite substantial across all items (with one exception), it is argued on the basis of the size of the introduced validity coefficients and other, logical considerations that paradoxically the confound had minimally distorting effects in estimating the BPAQ models selected for probing the extent of bias.     

Trait Stability and Continuity in Childhood: Relating Sociability and Hostility to the Five-Factor Model of Personality

We investigated the continuity of personality constructs in the Oregon Youth Substance Use Project, a cohort-sequential study encompassing development from early childhood to adolescence with five annual or biennial assessments. Sociability and Hostility, assessed by teachers' ratings of children's behaviors at each assessment, were related to the traits comprising the Five-Factor model assessed by teachers' ratings at the fifth assessment. Confirmatory factor analysis demonstrated that Sociability and Hostility were reliably measured at each assessment, and these constructs were relatively stable over time (mean rank-order stability coefficients over intervals of 1-5 years were .50 and .43, respectively). Sociability was most strongly associated (positively) with Extraversion, and Hostility was most strongly associated (negatively) with Conscientiousness and Emotional Stability. No differences were found for younger versus older children. Implications for measuring childhood personality traits using teachers' reports of early childhood behavior are discussed.     

特征类型在组合概念范畴效应中的作用

组合概念范畴效应是指,人们解释不同范畴组合概念的策略存在差异。本研究通过特征列举实验和建构路径模型,检验概念的特征类型在组合概念范畴效应中的作用。特征列举实验的结果表明,生物的实体特征比率高于人造物,而人造物的情境特征比率高于生物。路径分析的结果表明：⑴修饰词的实体特征比率显著影响属性解释比率,修饰词具有较多实体特征的组合概念得到属性解释的比率较高;⑵主名词的情境特征比率对关系解释比率的影响不显著;⑶将特征类型引入路径模型后,范畴对解释策略的影响依然显著。因此,范畴间的特征类型差异会影响组合概念范畴效应,但还存在其他影响因素有待进一步研究。     

名人广告效果的制约因素研究述评

系统回顾了影响名人广告效果的因素,指出名人广告的效果受名人可信度的影响,名人可信度包括吸引力、专业性与可靠性3个要素,专业性与可靠性对名人广告的效果具有积极的影响,吸引力对广告效果的影响受名人与商品的一致性以及消费者的精细加工水平的制约,精细加工可能性模型与意义迁移模型进一步说明了名人广告对消费者产生影响的具体过程,在名人广告中名人形象与商品形象的一致性是影响广告效果的决定性因素。