Multidimensional scaling of schematically represented faces based on dissimilarity estimates and evoked potentials of differences amplitudes

This study researches the input of the cerebral occipital and temporal cortex in the analysis of facial configuration and expressive characteristics. Analysis is based on the construction of a spherical model for the differentiation of schematically presented faces with quantitatively altering curvature of the mouth and brows. The model is designed using the method of multidimensional scaling of the dissimilarity judgments between stimuli (faces) and the amplitude of evoked potentials of differences (EPD) between abrupt stimulus changes recorded from the occipital and posterior temporal cortex. Analysis of the structure of the spherical model of facial differentiation depending on the electrode site and the latency of the EPD component within the duration of 120-240 ms has demonstrated that the activity of the occipital and posterior temporal cortex of the right hemisphere is associated with the emotional characteristics of the presented face, whereas facial configuration is reflected in the activation of both posterior temporal cortex and the occipital cortex of the left hemisphere. At all electrode sites maximum information of the emotional expression and configuration is represented in inter-peak amplitude P120-N180. With increasing latency there is increased distortion of the structure of differences in the spherical model of schematically presented faces, which is interpreted as an attenuation of electrical activity associated with the analysis of the emotional expression, which occurs more rapidly than configuration analysis.     

Infants' enumeration of actions: numerical discrimination and its signature limits

Are abstract representations of number – representations that are independent of the particular type of entities that are enumerated – a product of human language or culture, or do they trace back to human infancy? To address this question, four experiments investigated whether human infants discriminate between sequences of actions (jumps of a puppet) on the basis of numerosity. At 6 months, infants successfully discriminated four‐ versus eight‐jump sequences, when the continuous variables of sequence duration, jump duration, jump rate, jump interval and duration, and extent of motion were controlled, and rhythm was eliminated. In contrast, infants failed to discriminate two‐ versus four‐jump sequences, suggesting that infants fail to form cardinal number representations of small numbers of actions. Infants also failed to discriminate between sequences of four versus six jumps at 6 months, and succeeded at 9 months, suggesting that infants’ number representations are imprecise and increase in precision with age. All of these findings agree with those of studies using visual–spatial arrays and auditory sequences, providing evidence that a single, abstract system of number representation is present and functional in infancy.     

Categorization and abstraction abilities in 3-year-old children: a comparison with monkey data

Three-year-old children were tested on three categorization tasks of increasing levels of abstraction (used with adult baboons in an earlier study): the first was a conceptual categorization task (food vs toys), the second a perceptual matching task (same vs different objects), and the third a relational matching task in which the children had to sort pairs according to whether or not the two items belonged to the same or different categories. The children were tested using two different procedures, the first a replication of the procedure used with the baboons (pulling one rope for a category or a relationship between two objects, and another rope for the other category or relationship), the second a task based upon childrens prior experiences with sorting objects (putting in the same box objects belonging to the same category or a pair of objects exemplifying the same relation). The children were able to solve the first task (conceptual categorization) when tested with the sorting into boxes procedure, and the second task (perceptual matching) when tested with both procedures. The children were able to master the third task (relational matching) only when the rules were clearly explained to them, but not when they could only watch sorting examples. In fact, the relational matching task without explanation requires analogy abilities that do not seem to be fully developed at 3 years of age. The discrepancies in performances between children tested with the two procedures, with the task explained or not, and the discrepancies observed between children and baboons are discussed in relation to differences between species and/or problem-solving strategies.     

Confirmatory factor analysis using Microsoft Excel

This article presents a method for using Microsoft (MS) Excel for confirmatory factor analysis (CFA). CFA is often seen as an impenetrable technique, and thus, when it is taught, there is frequently little explanation of the mechanisms or underlying calculations. The aim of this article is to demonstrate that this is not the case; it is relatively straightforward to produce a spreadsheet in MS Excel that can carry out simple CFA. It is possible, with few or no programming skills, to effectively program a CFA analysis and, thus, to gain insight into the workings of the procedure.     

Microswitch programs for persons with multiple disabilities: an overview of the responses adopted for microswitch activation

Background: To introduce a person with multiple disabilities to a microswitch-aided program, one has to select a plausible response(s), that is, a response(s) that can be performed reliably and without excessive effort by the person and can successfully activate the microswitch(es) available (producing preferred stimuli). This paper provides an overview of the responses adopted for microswitch activation in research studies during the last 20 years. Method: Computerized and manual searches were carried out to identify the studies published between 1986 and 2005. Forty-eight research studies were identified. They concerned the use of (1) a single (typical) response, (2) a single (non-typical) response, (3) multiple (typical and non-typical) responses, and (4) multiple (vocal) responses. Results and discussion: The results showed that 151 of the 190 participants involved in the studies had a positive outcome (i.e., clear increases in their responding, which suggested that they had learned the association between responding and consequent preferred stimuli). Failures were largely concentrated in the first group of studies. The discussion focused on (a) the importance of selecting plausible responses for increasing the chances of success, (b) the need of non-typical responses for persons with minimal motor behavior, (c) implications of programs with multiple responses on engagement and choice, and (d) relevance of using vocal utterances. Some suggestions for future research concerning these points were also examined.     

Revisiting Hispanic Adolescents' Resilience to the Effects of Parental Problem Drinking and Life Stress

Two previous studies found that life stress and parental alcoholism were not as highly related to distress for Hispanic adolescents as they were for European American adolescents (M. Barrera Jr., S. A. Li, and L. Chassin, 1993, 1995). Those findings could be interpreted as evidence of Hispanic youths' resilience, but limitations of the stress measure and the homogeneity of the Hispanic sample threatened this interpretation. The present study improved on those previous studies by using a new measure of uncontrollable stressors and a more heterogeneous Mexican American sample. Participants in this study were 175 Mexican American and 59 European American adolescents and their parents. Unlike the previous studies, results did not show that Mexican American adolescents were more resilient to parental problem drinking or life stress than were European American adolescents. Overall, life stress was related to adolescents', mothers', and fathers' reports of adolescents' psychological distress above and beyond the effects of ethnicity and socioeconomic factors.