Is object recognition automatic?

A new paradigm is proposed that involves a simple judgment on an object’s perceptual feature that is independent of object identity. Subjects were required to categorize as vertical or horizontal the main axis of elongation of an object picture. Both fake and real-world objects were presented, and a graphical manipulation was applied to their shapes so that the canonical elongation of the real-world objects was incongruent with the elongation of their shapes after the manipulation. The results showed an influence of the identity of the objects on the perceptual task in the form of a cost in judging the elongation of the incongruent real-world objects. The results are taken as evidence for automatic activation of objects’ stored representations. A “horse-race” model of the influence of these representations on the perceptual task is proposed in the final section of the article.     

Different patterns of dissociation in unilateral spatial neglect

The aim of this paper is to discuss the issue of dissociations found in unilateral spatial neglect according to the modality of space exploration and the nature of the task. For this purpose we present a reanalysis of the data from a recent paper of Gentilini et al. (1989) comparing visual and blindfolded exploration of a computer keyboard and discuss the performance of a left-brain-damaged patient with right visuospatial neglect and left-sided neglect dyslexia. We conclude that unilateral spatial neglect cannot be interpreted as a disruption of a single attentional mechanism, but rather it reflects impaired attentional mechanisms at several levels of cognitive processing.     

Computing the COM from the COP in postural sway movements

A method is described for computing the centre of mass (COM) from empirical estimates of the centre of pressure (COP) obtained by means of a force platform. The method is based on a biomechanical model of sway movements in quiet standing, according to which the horizontal acceleration of the COM is approximately proportional to the COM–COP difference. The equations are solved by approximating the solution with best fitting spline functions. The implications for movement control are discussed.     

Are cognitive sex differences disappearing? Evidence from Spanish populations

Sex differences in cognitive abilities were determined using the norms from two standardizations of the Differential Aptitude Test (DAT) and the Primary Mental Abilities (PMA) conducted between 1979 and 1995 in Spain. The standardized sex differences (ds) were computed separately for the DAT and the PMA subscales. Males scored higher in the DAT subscales Verbal Reasoning, Numerical Ability, Spatial Relations and Mechanical Reasoning, as well as in the PMA subscales Numerical Ability and Mental Rotation. Females scored higher in Inductive Reasoning (PMA-R) in the 1979 and 1995 standardizations. Taken together, these data do not support the hypothesis that cognitive sex differences are disappearing: there are still some differences favoring females and still some differences favoring males.     

Uniqueness of three-mode factor models with sparse cores: The 3 × 3 × 3 case

Three-Mode Factor Analysis (3MFA) and PARAFAC are methods to describe three-way data. Both methods employ models with components for the three modes of a three-way array; the 3MFA model also uses a three-way core array for linking all components to each other. The use of the core array makes the 3MFA model more general than the PARAFAC model (thus allowing a better fit), but also more complicated. Moreover, in the 3MFA model the components are not uniquely determined, and it seems hard to choose among all possible solutions. A particularly interesting feature of the PARAFAC model is that it does give unique components. The present paper introduces a class of 3MFA models in between 3MFA and PARAFAC that share the good properties of the 3MFA model and the PARAFAC model: They fit (almost) as well as the 3MFA model, they are relatively simple and they have the same uniqueness properties as the PARAFAC model.This research has been made possible by a fellowship from the Royal Netherlands Academy of Arts and Sciences to the first author. Part of this research has been presented at the first conference on ThRee-way methods In Chemistry (TRIC), a meeting of Psychometrics and Chemometrics, Epe, The Netherlands, August 1993. The authors are obliged to Age Smilde for stimulating this research, and two anonymous reviewers for many helpful suggestions.     

Transforming three-way arrays to maximal simplicity

Transforming the core array in Tucker three-way component analysis to simplicity is an intriguing way of revealing structures in between standard Tucker three-way PCA, where the core array is unconstrained, and CANDECOMP/PARAFAC, where the core array has a generalized diagonal form. For certain classes of arrays, transformations to simplicity, that is, transformations that produce a large number of zeros, can be obtained explicitly by solving sets of linear equations. The present paper extends these results. First, a method is offered to simplifyJ ×J × 2 arrays. Next, it is shown that the transformation that simplifies anI ×J ×K array can be used to also simplify the (complementary) arrays of order (JK −I) ×J ×K, of orderI × (IK −J) ×K and of orderI ×J × (IJ −K). Finally, the question of what constitutes the maximal simplicity for arrays (the maximal number of zero elements) will be considered. It is shown that cases of extreme simplicity, considered in the past, are, in fact, cases of maximal simplicity.