Effects of power on perceived and objective group variability: evidence that more powerful groups are more variable

The perception of group variability is affected by social power and status. Three different mechanisms may be responsible for these effects: (a) the power of the perceiver affects perceived group variability; (b) the power of the perceived group affects its perceived variability; and (c) the power of the group affects its actual variability. Two studies are reported to tease apart these three mechanisms and provide support for the third. In the first study, high- and low-power groups interacted and subsequently judged each other. In the second study, participants observed and rated the Study 1 groups, either knowing their power relationship or not. Results suggest that members of high-power groups manifest greater interpersonal variability than members of low-power groups.     

Verbal and nonverbal interactions of four- and five-year-old friends in potential conflict situations

Dyads of 4- and 5-year-old friends and nonfriends attending preschools in central Italy were identified by friendship nominations. The 217 dyads of friends and non-friends participated in 2 closed-field tasks designed to simulate real-life situations of potential conflict. In the 4-year-old cohort, there were no significant differences in the behavior of the partners in either of the situations. However, at age 5 years, friends respected the rules of a fast-paced competitive game significantly more than did nonfriends. In discussing how to share a single object (a chocolate egg with a toy inside), 5-year-old friends were more likely to reach agreement than were nonfriends. The results suggest important developmental changes in the processes of negotiation and sharing within the preschool years.     

Experiences of longing in Norwegian and Swedish 4- and 5-year-old children

Longing can be defined as a blend of the primary emotions of happiness and sadness. These primary emotions are experienced very early by children, and the meanings of the words happiness and sadness are also known by children early in their verbal development. To find out at what age children are able to understand and use the more developed concept of longing, the authors interviewed 74 preschoolers (4- and 5-year-olds) in Norway and Sweden about their experiences of longing. Chi-square analyses showed age and sex differences in knowledge of the concept, and some differences between categories of longing were also significant. Results showed that young children's ability to understand and use the concept of longing appears to be limited and that girls seem to mature earlier in this respect than boys do.     

Contextual control of equivalence-based transformation of functions

The transformation of functions refers to the untrained acquisition of stimulus functions among members of stimulus equivalence classes or relational frames. Although it is widely assumed that contextual control over the transformation of fuctions must exist, this has not yet been conclusively demonstrated in laboratory studies. Four experiments are reported in which (a) stimulus equivalence classes were established, (b) a conditional stimulus function was trained for one member of each of the classes, and (c) multiple-exemplar procedures were used to train and test for contextual control over the transformation of the stimulus function within the classes and to assess whether it generalized to new equivalence classes. Although a significant amount of training was required, the procedures ultimately resulted in the contextual control of function transformation for 9 of 10 participants and generalized contextual control for 4 of 5 participants.     

Peculiar aspects of reading and writing performances in patients with olivopontocerebellar atrophy

Olivopontocerebellar atrophy (OPCA) is a still debated condition, of which motor disruption is the most common feature. A high incidence of associated mood disorders may exist, but there are few studies on concomitant cognitive impairment. Our aim was to assess whether there is reading and writing disruption in olivopontocerebellar atrophy (OPCA). 6 patients were administered different reading and writing tasks. Scores were then compared to those obtained by healthy volunteers. There was an evident impairment in reading and writing execution in our patients compared to those of the control group. On the contrary, no difference could be found in abstraction, problem-solving, and memory tasks. We discuss the results, debating the role of the cerebellum in the conscious process of cognition or in ocular movement control (necessary for reading and writing fluidity and effective execution) and in the dynamic activation of all the cerebral cortex mediated by the diffuse projection to the reticular system.     

Sex differences on the serial color-word test

The Serial Color-Word Test was administered to nonclinical volunteers of three age strata (17-29, 30-45, 46-65 yr.). Sex differences on the 17 variables of the test were explored for each age stratum. Only six significant intersex differences were found. In all age strata women scored significantly higher on linear regression of reading times in one of the last two subtests, i.e., R4 or R5.     

Modeling of human posturokinetic movements by a linear feedback system: relations among feedback coefficients

This study describes a method of modeling human trunk and whole body backward bending and suggests a possible neural control strategy. The hypothesis was that the control system can be modeled as a linear feedback system, in which the torque acting at a given joint is a function of the state variables (angular positions and angular velocities). The linear system enabled representation of the feedback system by a gain matrix. The matrix was computed from the kinematics recorded by a movement analysis system and from the joint torques calculated by inverse dynamics. To validate the control model, a comparison was made between the angular kinematics yielded by the model and the experimental data. Moreover, for all subjects, the same relationships between feedback coefficients were found although gain values were different. The study showed that the feedback system is an appropriate model of the strategy from performing an accurate controlled trunk or whole body backward bending in the sagittal plane.     

Deformation of the useful visual field with state of vigilance,task priority,and central task complexity

In a dual-task situation, peripheral perception can deteriorate due to different variables related to the experimental situation, such as central task complexity and the relative priority given to the two tasks. Recent studies have also shown that individual characteristics (such as the state of vigilance) can alter the useful visual field. The ability to perceive signals presented at different places in the visual field decreases in situations that lead to episodes of low vigilance. In Exp. 1, 27 subjects (18-29 years) had to perform a monotonous and prolonged dual-monitoring task involving central and peripheral vision. The test was carried out with two different sets of instructions regarding priority: the more important task was either the central task or the peripheral one. In Exp. 2, 18 subjects (18-30 years) performed the same test, but this time with two levels of complexity of the central task, either a simple monitoring activity or the same monitoring task coupled with a counting activity. Elliptical interpolation of the data enabled assessment of the deformation of the useful visual field in both experiments. The analysis of the parameters of the elliptical model indicated that the useful visual field mainly shrinks on the vertical axis, as the individual becomes drowsy. The useful visual field also shrinks on the horizontal axis when the peripheral task has priority and the monitoring activity is prolonged, or when the central task is complex.     

Color of computer display frame in work performance, mood, and physiological response

The effects of the color of a personal computer screen on work performance, psychological mood, and autonomic response were investigated. 24 subjects were asked to perform visual tasks presented on the computer display. Three types of computer monitor, which were colored red, blue, or beige, were employed to present visual cognitive tasks. The mood measure, the Japanese Stress Arousal Check List, and heart rate measurement were administered before and after work on each color of computer monitor. Analysis of a low-demand task (Exp. 1) showed that the red computer monitor reduced visual task performance compared to that with the blue, while the blue monitor decreased visual task performance on a high-demand task (Exp. 2). The color of the monitor did not affect mood or heart rate. Based on these findings, the effect of the color of environmental cues on work was discussed.     

Cognitive deficits in major depression

Major depression is a mood disorder that is often accompanied by the impairment of cognitive functions. Although suggestive, the large range of existing neuropsychological, neuropsychiatric, and, lately, neuroimaging investigations have not yet given a consistent picture of the psychological and biological disturbances involved in this psychiatric disorder. The present study of the cognitive functions in depression was part of an extensive investigation, including neuropsychological testing, psychiatric examination, and neuroimaging. A representative sample of 40 severely depressed hospitalized patients and a group of 49 closely matched control subjects were tested with an extensive neuropsychological test battery. Results, corrected for various confounding factors, confirmed the current notion that depressed patients suffer from wide-spread cognitive impairments. The group analysis did not allow any hypothesis on a possible pattern to the dysfunctions, but heterogeneity in the test performances calls for further analysis of the data in patient subgroups in relation to neuroimaging results.