Parental loss of close family members and propensities towards absorption in offspring

Parental unresolved/disorganized responses to loss assessed in the Adult Attachment Interview predict infant disorganized (D) attachment. Parental experiences of loss near the birth of an infant should therefore increase the likelihood of D attachment to that parent. Liotti (1992) suggested that D attachment may increase tendencies to altered states of consciousness, and some support for this hypothesis has been obtained in clinical and high-risk samples. Here, Tellegen's Absorption Scale was used to measure propensities to altered consciousness in two low-risk samples of young adults (N=136, N=308). In both studies, participants whose parents experienced familial loss within two years of their birth showed elevated levels of absorption. These outcomes (a) support the proposed connection between disorganized attachment and tendencies to altered consciousness, and (b) suggest that queries regarding parental loss experiences should be further explored as a ‘rough and ready’ estimate of disorganized attachment in large-scale studies.     

Symmetry and selective attention: A dissociation between effortless perception and serial search

It is widely assumed that symmetry is an important visual primitive, probably encoded without the need for attention. Julesz’s (1981) definition ofeffortless perception, which states that any stimulus property perceived for exposure durations of 160 msec or less is detected preattentively, contributed greatly to this belief.Single pattern studies confirm that symmetry is detected within this limit. In the present study, however, Julesz’s operationalization is compared with themultiple pattern visual search task, to see whether symmetry as a wholistic property is detected in parallel. The results show that symmetry detection times are highly dependent on the number of distractor patterns. The findings are similar for dot patterns, wire polygons, solid block shapes, and simple parentheses. We conclude that symmetry detection per se requires selective attention, but that some related grouping or segmentation mechanism may operate preattentively.     

Robust canonical discriminant analysis

A method for robust canonical discriminant analysis via two robust objective loss functions is discussed. These functions are useful to reduce the influence of outliers in the data. Majorization is used at several stages of the minimization procedure to obtain a monotonically convergent algorithm. An advantage of the proposed method is that it allows for optimal scaling of the variables. In a simulation study it is shown that under the presence of outliers the robust functions outperform the ordinary least squares function, both when the underlying structure is linear in the variables as when it is nonlinear. Furthermore, the method is illustrated with empirical data.The research of the first author was supported by the Netherlands Organization of Scientific Research (NWO grant 560-267-029).     

A solution to the effect of sample size on outlier elimination

Results from a Monte Carlo study demonstrate how a non-recursive, a simple recursive, a modified recursive, and a hybrid outlier elimination procedure are influenced by population skew and sample size. All the procedures are based on computing a mean and a standard deviation from a sample in order to determine whether an observation is an outlier. Miller (1991) showed that the estimated mean produced by the simple non-recursive procedure can be affected by sample size and that this effect can produce a bias in certain kinds of experiments. We extended this result to the other three procedures. We also create two new procedures in which the criterion used to identify outliers is adjusted as a function of sample size so as to produce results that are unaffected by sample size.     

A multi-dimensional model for treating families that have survived mother assault

This paper offers a multidimensional family systems approach to treating children and their mothers in families who have survived violence and are in father-absent families. The model incorporates theoretical and clinical ideas from the child witness-to-violence field, the field of traumatic stress, and from feminist thinking. Three areas of intervention are detailed.The authors gratefully acknowledge the suggestions of the reviewers.     

Measurement of forearm rotation: The technique,and its reproducibility and validity

Forearm rotation is a point of interest in the study of human movement. For the most part, earlier methods for determining this joint rotation could be applied only in restricted situations. In this paper, a new technique is described, which involves the use of a three-dimensional opto-electronic motion registration system. With only two cameras, the supination angle in almost every position can be determined. A bracelet is attached to the subject’s forearm and fixed to the radius. Wrist points are defined in relation to this bracelet (in its local coordinate system). The properties of the bracelet allow the motion-registration system to calculate its position in the global coordinate system. Given the position of the bracelet, the shoulder, and the elbow, the rotation angle can be determined. The reproducibility (error less than 2^o) of and validity of the technique are also discussed.     

Discrimination of 3-D shape and 3-D curvature from motion in active vision

We examined the ability of human observers to discriminate between different 3-D quadratic surfaces defined by motion, and with head position fed back to the stimulus to provide an up-to-date dynamical perspective view. We tested whether 3-D shape or 3-D curvature would affect discrimination performance. It appeared that discrimination of 3-D quadratic shape clearly depended on shape but not on the amount of curvature. Even when the amount of curvature was randomized, subjects’ performance was not altered. On the other hand, the discrimination of 3-D curvature clearly depended linearly on curvature with Weber fractions of 20% on the average and, to a small degree, on 3-D shape. The experiment shows that observers can easily separate 3-D shape and 3-D curvature, and that Koenderink’s shape index and curvedness provide a convenient way to specify shape. These results warn us against using just any arbitrary 3-D shape in 3-D shape perception tasks and indicate, for example, that emphasizing 3-D shape in computer displays by exaggerating curvature does not have any effect.     

Linear relations amongk sets of variables

A family of solutions for linear relations amongk sets of variables is proposed. It is shown how these solutions apply fork=2, and how they can be generalized from there tok3.The family of solutions depends on three independent choices: (i) to what extent a solution may be influenced by differences in variances of components within each set; (ii) to what extent the sets may be differentially weighted with respect to their contribution to the solution—including orthogonality constraints; (iii) whether or not individual sets of variables may be replaced by an orthogonal and unit normalized basis.Solutions are compared with respect to their optimality properties. For each solution the appropriate stationary equations are given. For one example it is shown how the determinantal equation of the stationary equations can be interpreted.