Visual attention in infants with perinatal brain damage: Evidence of the importance of anterior lesions

Shifts of visual attention can be studied in adults and infants by cueing responses to a particular spatial location. Earlier studies have shown that by seven months of age normal infants show a similar pattern of facilitation and inhibition to a cued spatial location as adults. In this study we report data from infants with perinatal lesions that include or exclude the left anterior quadrant. Results indicate that infants with left anterior lesions do not show facilitation to a cued spatial location in this task. In contrast, infants with posterior lesions showed the same pattern of performance as healthy subjects. While these findings differ from those obtained with adults, they are consistent with previous studies of children with perinatal lesions, and with findings from ERP studies with normal infants.     

The distribution of chance congruence coefficients from simulated data

All attempts to study the stability of factors depend on having some useful statistic that measures the degree of similarity between factors. This study attempts to provide some normative data about the distribution of one measure of similarity, the congruence coefficient, through a Monte Carlo technique. The matching of “chance” factor patterns was done by the method of Tucker. Statistical tests of the results, based on similarities of the method to canonical and multiple correlation, seemed satisfactory. The tabled results can be used as guides to the significance of congruence coefficients for some cases. The consistencies of the data indicate that a functional resolution may be possible, but none was found.     

Psychological correlates of the French sound system

Six samples of CCVC phoneme sequences were devised to represent linguistically specifiable distances from existing French words, distance being measured in terms of number of substitutions needed to make an existing French word. Fifty-four native speakers of French rated the sound sequences for their subjective proximity to French, using ungraded rating scales. Results showed a general correspondence between the linguistic and psychological measurements, although certain phoneme sequences did not follow the predicted order. These were examined to see if their displacement could be attributed to the number of different French words reached through substitutions.     

A scalar product model for the multidimensional scaling of choice

A multidimensional scaling analysis is presented for replicated layouts of pairwise choice responses. In most applications the replicates will represent individuals who respond to all pairs in some set of objects. The replicates and the objects are scaled in a joint space by means of an inner product model which assigns weights to each of the dimensions of the space. Least squares estimates of the replicates' and objects' coordinates, and of unscalability parameters, are obtained through a manipulation of the error sum of squares for fitting the model. The solution involves the reduction of a three-way least squares problem to two subproblems, one trivial and the other solvable by classical least squares matrix factorization. The analytic technique is illustrated with political preference data and is contrasted with multidimensional unfolding in the domain of preferential choice.The present work was initiated at Oregon Research Institute under National Institute of Mental Health Grant MH 12972. It was reformulated and completed while the first author was a Visiting Research Fellow at Educational Testing Service.Presently at the Department of Mathematics, University of Toronto.     

The role of correlated factors in factor analysis

The fundamental factor theorem is developed in matrix form for the case of correlated factors. The properties of the correlated factor system are discussed, and some effects of sampling error considered. The psychological meaning of correlated factors is discussed, and several mechanisms by which general factors may operate in the factorial system are indicated.