STRUCTURE IN SIMILARITY MATRICES

Waern, Y. Structure in similarity matrices. A graphic approach. Scand. J. Psychol ., 1972, 13 , 5–16.—The present paper proposes a simple method for representing the structure inherent in the similarity matrix, i.e. a graphic representation. The traditional multidimensional scaling methods are compared with each other and with the graphic representation with regard to representation, interpretation and assumptions concerning the subject's performance. The graph gives a topological representation and the derivation of the graph from the similarity matrix may be made so as to reduce the demands on the subjects somewhat. As to interpretation, the graph is able to reveal dimensions, clusters, and hierarchies. Compared with some multidimensional scaling it gives very similar interpretations.     

Loss of negative priming following sleep deprivation

It has been argued that one night of sleep loss in young healthy adults produces changes similar to that associated with normal, healthy ageing—in particular, that young sleep-deprived adults perform similarly to 60-year-old sleep-satiated adults on some tasks of frontal lobe function. This proposition was examined using a protocol viewed by many to be a direct probe of nonvolitional attention mechanisms associated with frontal lobe function. A negative priming (NP) procedure was used to compare performance between non-sleep-deprived (NSD) and sleep-deprived (SD, 34 hr) young, healthy adults. This protocol allowed for exploration of two theories of the NP effect based on inhibitory or memorial processes. Under conditions believed to facilitate inhibitory processes a normal NP effect was found for NSD(16 ms) and SD (9 ms) participants. Under conditions believed to rely on memorial processes there was no NPeffect following SD, compared with a normal NP effect for NSD participants (11 ms). Distractor interference was also greater following SD. These findings do not suggest a similar pattern of change following sleep loss in healthy young adults to that of normal, healthy, non-sleep-deprived aged groups.     

The myth of a new tolerance for old differences: A rebuttal to meacham

This piece responds to Meacham's (1994) suggestion that prejudice may be replaced by tolerance through the simple understanding of two forms of individualism that may be expressed by members of society—that is, that if we move from a self-contained to an ensembled individualism, we will treat those different from ourselves in a more tolerant fashion. This model is criticized for its emphasis on tolerance of, rather than respect for, all groups in society and, furthermore, for its bias toward groups that are more highly valued by the current society.     

Gender-Role Cognition in Three-Year-Old Boys and Girls

Although the multidimensionality of gender roles has been well established, few researchers have investigated male and female roles separately. Because of the substantial differences in the ways male and female roles are portrayed in our culture, boys and girls may think and learn about these roles differently. The male role is more clearly defined, more highly valued, and more salient than the female role; thus, children's cognitions about these two roles may be expected to differ. The present study addressed the question of whether there is sex-typical variation in gender labeling, gender-role knowledge, and schematicity. Participants were 120 families; 15% were from minority ethnic groups, and 17% were single-parent families; 25% of the parents had a high school education or less. Results indicated that at 36 months of age, boys were less able to label gender and less knowledgeable about gender roles than were girls. Boys' knew more about male stereotypes than female stereotypes, whereas girls knew considerably more than boys about the female role and as much as boys about the male role. Boys and girls were found to be similar in gender schematicity. Traditionality of parental attitudes regarding child-rearing and maternal employment were not strongly related to children's gender cognition.     

It's not just what you say,it's how you say it too. Adolescents' hostile attribution of intent and emotional responses to social comments

A highly prevalent and relevant situation in which adolescents have to interpret the intentions of others is when they interact with peers. We therefore successfully introduced a new paradigm to measure hostile attribution bias (HAB) and emotional responses to such social interactions and examined how it related to youth's aggressiveness. We presented 881 adolescents (M_age = 14.35 years; SD = 1.23; 48.1% male) with audio fragments of age-mates expressing social comments that varied in content (e.g., what the person says) and tone of voice (e.g., how the person says it). Participants' peers also reported on their aggressiveness. In general, added negativity of content and tone was driving the youth's intent attribution and emotional responses to the comments. In line with the Social Information Processing model, we found more hostile attribution of intent and more negative emotional responses of aggressive youth to ambiguous stimuli. Aggression was also related to more hostile intent attributions when both content and tone were negative. Unlike most studies on HAB, the aggression effects in the current study emerged for girls, but not boys. Implications of these results and future use of the experimental paradigm are discussed.     

Differences in postural control and movement performance during goal directed reaching in children with developmental coordination disorder

Poor upper-limb coordination is a common difficulty for children with developmental coordination disorder (DCD). One hypothesis is that deviant muscle timing in proximal muscle groups results in poor postural and movement control. The relationship between muscle timing, arm motion and children's upper-limb coordination deficits has not previously been studied. The aim of this study was to investigate the relationship between functional difficulties with upper-limb motor skills and neuromuscular components of postural stability and coordination. Sixty-four children aged 8-10 years, 32 with DCD and 32 without DCD, participated in the study. The study investigated timing of muscle activity and resultant arm movement during a rapid, voluntary, goal-directed arm movement. Results showed that compared to children without DCD, children with DCD took significantly longer to respond to visual signals and longer to complete the goal-directed movement. Children with DCD also demonstrated altered activity in postural muscles. In particular, shoulder muscles, except for serratus anterior, and posterior trunk muscles demonstrated early activation. Further, anterior trunk muscles demonstrated delayed activation. In children with DCD, anticipatory function was not present in three of the four anterior trunk muscles. These differences support the hypothesis that in children with DCD, altered postural muscle activity may contribute to poor proximal stability and consequently poor arm movement control when performing goal-directed movement. These results have educational and functional implications for children at school and during activities of daily living and leisure activities and for clinicians assessing and treating children with DCD.     

Motor fluency deficits in the sequencing of actions in schizophrenia

Many everyday activities depend on the capacity to organize and smoothly execute motor sequences. The authors tested the hypothesis that a sequencing deficit is associated with schizophrenia. They used a new method to distinguish between lower and higher order mechanisms for the impairment. The 1st task involved triggered sequences in which sensory information from 1 movement was the cue for initiation of the following movement. Results showed that the motor sequences were performed as fluently in patients as in controls. The 2nd and 3rd tasks involved sequences in which the entire movement sequence could be preplanned. Patients executed the sequences less fluently than controls but only under the condition where action sequences were required. Furthermore, the patients' fluency deficit increased with sequence complexity. The high discrimination power of Task 3 gave the authors a means to control for a potential psychometric confound involving differential discriminating power and to argue in favor of a specific higher order motor fluency deficit in patients with schizophrenia. It is suggested that basic lower order mechanisms that integrate sensory information with outgoing motor commands are preserved in schizophrenia, whereas higher order integrative mechanisms that are required for the smooth coordination of motor sequences are impaired.