Local homogeneity in latent trait models. A characterization of the homogeneous monotone irt model

The stochastic subject formulation of latent trait models contends that, within a given subject, the event of obtaining a certain response pattern may be probabilistic. Ordinary latent trait models do not imply that these within-subject probabilities are identical to the conditional probabilities specified by the model. The latter condition is called local homogeneity. It is shown that local homgeneity is equivalent to subpopulation invariance of the model. In case of the monotone IRT model, local homogeneity implies absence of item bias, absence of item specific traits, and the possibility to join overlapping subtests. The following characterization theorem is proved: the homogeneous monotone IRT model holds for a finite or countable item pool if and only if the pool is experimentally independent and pairwise nonnegative association holds in every positive subpopulation.This research was supported by the Dutch Interuniversity Graduate School of Psychometrics and Sociometrics. The authors wish to thank two reviewers for their thorough comments.     

Development of animal recognition: a difference between Parts and Wholes

A series of experiments examined children's recognition of animals by their features (Parts) and by the relative scale of the parts (Wholes). They were asked to identify the correct picture of an animal they could name from the original plus two computer-generated alternatives. We examined the developmental trends associated with upright (Studies 1 and 3) and inverted presentations (Study 3). Both experiments confirmed children's superior ability in dealing with the recognition of animal Parts over animal Wholes, especially for the younger ages tested (6- and 10-year-olds). It was not until the ages of 15-16 that children demonstrated equal performance on Whole and Part items. The late acquisition of animal Whole recognition is compared to the late acquired configural skills proposed for face recognition.     

More accurate size contrast judgments in the Ebbinghaus Illusion by a remote culture

The Ebbinghaus (Titchener) illusion was examined in a remote culture (Himba) with no words for geometric shapes. The illusion was experienced less strongly by Himba compared with English participants, leading to more accurate size contrast judgments in the Himba. The study included two conditions of inducing stimuli. The illusion was weaker when the inducing stimuli were dissimilar (diamonds) to the target (circle) compared with when they were similar (circles). However, the illusion was weakened to the same extent in both cultures. It is argued that the more accurate size judgments of the Himba derive from their tendency to prioritize the analysis of local details in visual processing of multiple objects, and not from their impoverished naming.     

Priming of plane-rotated objects depends on attention and view familiarity

Three experiments investigated the role of attention in visual priming across rotations in the picture plane. Experiment 1 showed that naming latencies increased with the degree of misorientation for objects commonly seen in an upright view (base objects) but not for objects seen familiarly from many views (no-base objects). In Experiment 2, no-base objects revealed a priming pattern identical to that observed previously for left–right reflections (Stankiewicz, Hummel, & Cooper, 1998 Stankiewicz, B. J., Hummel, J. E. and Cooper, E. E. 1998. The role of attention in priming for left–right reflections of object images: Evidence for a dual representation of object shape. Journal of Experimental Psychology: Human Perception and Performance, 24(3): 732–744. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]): Attended objects primed themselves in the same and rotated views, whereas ignored images primed themselves only in the same view, with additive effects of attention and orientation. In Experiment 3 ignored base objects only primed themselves in a familiar (upright) view, indicating that priming only obtains when that image makes contact with object memory. These data challenge theories of object recognition that rely on any single representation of shape and contribute to evidence suggesting holistic (view-like) representations for ignored and analytic (view-insensitive) representations for attended objects.     

Integrating Sociological and Psychoanalytic Concepts by Otto Pollak

The total data set for this study consisted of 958 critical incidents from high and low cohesion sessions in person-centered group psychotherapy. These incidents were typically noted on a group climate questionnaire at the end of each session. Altogether 211 clients and students participated in twenty-six groups.

The high cohesion sessions were dominated by the following cohesion dimensions in rank order: self-disclosure and feedback (24.0%); attraction and bonding (20.2%); listening and empathy (20.0%); process performance and goal attainment (15.0%); and support and caring (10.6%). The corresponding rank order for the low cohesion sessions was strikingly different: avoidance and defensiveness (43.5%); conflict and rebellion (22.2%); and selfdisclosure and feedback (8.9%).

Apparently then, there are very different patterns of critical incidents in high and low cohesion sessions of group psychotherapy.