In human adults two functionally and neuro‐anatomically separate systems exist for the use of visual information in perception and the use of visual information to control movements (Milner & Goodale, 1995 , 2008 ). We investigated whether this separation is already functioning in the early stages of the development of reaching. To this end, 6‐ and 7‐month‐old infants were presented with two identical objects at identical distances in front of an illusory Ponzo‐like background that made them appear to be located at different distances. In two further conditions without the illusory background, the two objects were presented at physically different distances. Preferential reaching outcomes indicated that the allocentric distance information contained in the illusory background affected the perception of object distance. Yet, infants' reaching kinematics were only affected by the objects' physical distance and not by the perceptual distance manipulation. These findings were taken as evidence for the two‐visual systems, as proposed by Milner and Goodale ( 2008 ), being functional in early infancy. We discuss the wider implications of this early dissociation. 相似文献
We examined cross-sectional differences and longitudinal changes in episodic memory performance related to impending death among a group of very old people, aged 90–101 years. Participants were assessed at 3 measurement points across a 6-year interval. Three groups were identified: those who survived the entire follow-up period (n =40), those who died before the first follow-up (n =44), and those who died after the first follow-up (n =14). Participants completed a battery of episodic memory tasks consisting of face recognition, word recognition, word recall, and object recall with selective reminding. Those who survived performed better than those who were going to die in object recall at baseline. A Cox regression analysis, controlling age, revealed that object recall performance was significantly related to subsequent mortality status. Longitudinal analyses demonstrated significant 3-year decline for both face recognition and object recall, but no evidence of differential decline as a function of mortality group. Thus, longitudinal changes in memory preceding death were not as pronounced as the corresponding cross-sectional differences in this very old sample. In general, the results suggest that mortality-related memory deficits are present in extreme old age, although these deficits are relatively small and task-specific. 相似文献
L'Analyse de Fréquence des Configurations (AFC) est une méthode de recherche des classes et anticlasses dans les classifications croisées de catégories de variables. Les classes sont des modèles de catégories de variables qui apparaissent plus souvent que le hasard ne le laisse supposes. Les anticlasses sont des modèles de catégorie de variables qui apparaissent moins souvent que le hasard ne le laisse supposes. On présente quatre applications d'AFC: l'AFC de premier ordre, l'AFC prédictive, l'AFC de symétrie axiale, et un modèle d'AFC longitudinale. On examine les caractéristiques de l'AFC en insistant sur les contraintes et l'applicabilité. On compare aussi l'AFC avec d'autres méthodes permettant l'analyse multivariée de catégories de données, en particulier la modèlisation log-linéaire. Des sorties informatiques sont traitées. Configural Frequency Analysis (CFA) is a method for the search for types and antitypes in cross-classifications of categorical variables. Types are patterns of variable categories that occur more often than expected from chance. Antitypes are patterns of variable categories that occur less often than expected from chance. Four applications of CFA are reviewed: the First Order CFA, the Prediction CFA, Axial Symmetry CFA, and one model of Longitudinal CFA. Characteristics of CFA are discussed, focusing on constraints posed and applicability. Comparisons are made of CFA with other methods for multivariate analysis of categorical data, in particular, log-linear modelling. Computational issues are discussed. 相似文献
Missing values at the end of a test typically are the result of test takers running out of time and can as such be understood by studying test takers’ working speed. As testing moves to computer-based assessment, response times become available allowing to simulatenously model speed and ability. Integrating research on response time modeling with research on modeling missing responses, we propose using response times to model missing values due to time limits. We identify similarities between approaches used to account for not-reached items (Rose et al. in ETS Res Rep Ser 2010:i–53, 2010) and the speed-accuracy (SA) model for joint modeling of effective speed and effective ability as proposed by van der Linden (Psychometrika 72(3):287–308, 2007). In a simulation, we show (a) that the SA model can recover parameters in the presence of missing values due to time limits and (b) that the response time model, using item-level timing information rather than a count of not-reached items, results in person parameter estimates that differ from missing data IRT models applied to not-reached items. We propose using the SA model to model the missing data process and to use both, ability and speed, to describe the performance of test takers. We illustrate the application of the model in an empirical analysis.
Ohne Zusammenfassung
Die folgende Abhandlung ist die bedeutend erweiterte Ausarbeitung eines Vortrages, welcher am 9. Januar 1929 in einer Allgemeinen
Versammlung der Zoologisch-Botanischen Gesellschaft in Wien, am 15. Oktober 1929 vor der Gesellschaft für empirische Philosophie
in Berlin und am 30. Oktober 1929 in der Kantgesellschaft Karlsruhe gehalten wurde. Bei der Ausarbeitung wurde vor allem Bedacht
genommen, Tatsachen und Theorien, die sich bereits in des Verf.s „Kritischer Theorie der Formbildung” (Schaxels Abh. z. th.
B. 27, Berlin 1928) dargestellt finden, nur kurz zu behandeln, andererseits aber das genannte Werk hier durch die Verarbeitung
der dort noch nicht behandelten Ergebnisse zu erg?nzen. Auch in die Literaturangabe wurden im allgemeinen nur an jenem Orte
nicht angegebene Werke aufgenommen. Auf das erw?hnte Buch, das eine umfassende, kritische Darstellung der Theorien der Formbildung
zum Ziele hat, sei hier ein für allemal hingewiesen. 相似文献