The gap between rod and frame influences the rod-and-frame effect with small and large inducing displays

The role of the spatial separation between the ends of a rod and a frame’s inner edge (gap) in modulating the rod-and-frame effect (RFE) has been studied here with frames subtending either large or small retinal angles. With a large frame, rod settings were always in the direction of frame tilt (direct effects) and varied inversely with gap size. With a small frame, rod settings were in the direction of frame tilt for tilts between 7.5° and 15°; with larger frame tilts, rod settings in the direction opposite that of the frame were observed (indirect effects). Increasing gap size produced a tendency toward negativity (away from frame tilt). Consequently, direct effects were larger for small gaps, while the opposite was true for indirect effects. Overall, these results point to the importance of gap size in modulating the RFE, for both large and small displays.     

Local and global visual mechanisms underlying individual differences in the rod-and-frame illusion

The role of local and global visual mechanisms in individual differences in the rod-and-frame (RF) effect was investigated. Field-dependent and field-independent observers, selected on the basis of Witkin and Asch’s (1948) classical procedure, were submitted to the small RF test (Coren & Hoy, 1986). Four frame tilts and two gap sizes were used. As expected, direct effects (i.e., rod settings in the direction of frame tilt) were observed at small degrees of frame tilt, while indirect effects (i.e., rod settings in the direction opposite that of frame tilt) were observed at larger frame tilts. Fielddependent observers showed larger direct effects in the case of the small gap. Indirect effects were comparable in both field-dependent and field-independent subjects, regardless of gap size. Following the model proposed by Wenderoth and Johnstone (1987), these findings indicate that low-level visual mechanisms, responsible for local orientation interactions, have a different gain in fielddependent and field-independent individuals. In contrast, global visual mechanisms, presumably acting     

Multiple stimulus presentation yields larger deficits in children with developmental dyslexia: A study with reading and RAN-type tasks

In this study, we examined the effect of multiple versus single stimulus presentation in typically developing readers and children with developmental dyslexia. The tasks involved either reading single words or arrays of words or naming single or multiple colors and digits (rapid automatized naming or RAN). To be able to compare these sets of conditions, we recorded total response times (i.e., the time between stimulus onset and the end of the participant’s vocal response) in all cases. The study included 43 typically developing readers and 25 children with dyslexia.

Results indicate that typically developing readers have a clear advantage with multiple over single items on both RAN and reading tasks. The children with dyslexia showed a moderate advantage for multiple stimuli in naming colors and digits but presented the opposite pattern in reading.

With regard to reading, the disproportionate impairment of the children with dyslexia in dealing with multiple arrays suggests difficulty in integrating the multiple subcomponents of the reading task over and above the basic nuclear deficit in decoding words. Regarding the RAN tasks, results confirm that the requirement of integrating multiple subcomponents may be critical in mediating the predictive value of these measures on reading.     

Psychiatric chrono‐epidemiology: its relevance for the study of aggression

Chrono‐epidemiology is the study of the distribution of health events according to time. The time intervals taken into account have cyclic patterns and include circadian, weekly, seasonal, and circannual rhythms. In the behavioural field, chrono‐epidemiology can be and has been applied to studies concerning the causes of death (suicide and homicide), clinical events such as admissions to and contacts with mental healthcare services, and the seasonal distribution of crime involving the use of violence. Frequently reported findings include clear circadian and seasonal rhythms present in the phenomenon of suicide (rhythms more evident in the case of violent suicide); seasonal rhythms in the expression of aggression by patients hospitalised for mental illness; and a circannual recurrence of crimes with a violent component. The intrinsic circadian and seasonal rhythms of some neuronal systems, particularly those of serotonin, involved in the control of mood and impulses, are thought to favour the behavioural rhythms observed, although the contribution of socio‐environmental factors, such as the fluctuation of supportive networks according to time, is also acknowledged. By demonstrating non‐casual recurrence of certain behaviour and by exploring the socio‐biological basis of the rhythms beneath these recurrences, chrono‐epidemiology may offer important etiologic and preventive clues to the understanding of the biological and environmental correlates of aggressive behaviour. Aggr. Behav. 28:477–490, 2002. © 2002 Wiley‐Liss, Inc.     

Unemployment and Life Satisfaction: The Moderating Role of Time Structure and Collectivism1

This study investigated the mitigating role of collectivism and time structure in reaction to unemployment. Participants (N= 229) with different occupational status (employed, students, unemployed) coming from either northern or southern Italy were compared with regard to general life satisfaction. Unemployed were found to show lower life satisfaction. self‐esteem, and happiness than were employed peers or students, but these effects were found to be influenced by both collectivism and time structure. Life satisfaction was lower among unemployed from northern Italy (where individualistic norms prevailed) than from southern Italy (which was found to be more collectivist). Also, among unemployed, life satisfaction tended to be higher among those who perceived their use of time as more structured and purposive. The results suggest that unemployment may have less severe consequences in a collectivistic culture and for people with good time‐structure abilities.     

Simultaneous classification and multidimensional scaling with external information

For the exploratory analysis of a matrix of proximities or (dis)similarities between objects, one often uses cluster analysis (CA) or multidimensional scaling (MDS). Solutions resulting from such analyses are sometimes interpreted using external information on the objects. Usually the procedures of CA, MDS and using external information are carried out independently and sequentially, although combinations of two of the three procedures (CA and MDS, or multidimensional scaling and using external information) have been proposed in the literature. The present paper offers a procedure that combines all three procedures in one analysis, using a model that describes a partition of objects with cluster centroids represented in a low-dimensional space, which in turn is related to the information in the external variables. A simulation study is carried out to demonstrate that the method works satisfactorily for data with a known underlying structure. Also, to illustrate the method, it is applied to two empirical data sets.     

The effects of the constancy of location and order in working memory visual–phonological binding of children with dyslexia

It has been suggested that children with dyslexia have difficulties in visual–phonological working memory (WM) binding, supporting the hypothesis that this ability is crucial in the formation of associations between written forms and phonological codes required by reading. However, research on this topic is currently scarce and has not clarified to what extent binding may be supported by spatial and temporal information. The present study examined visual–phonological WM binding performance in a group of children with dyslexia compared to a control group of typically developing children matched for age, gender, and grade. Children had to memorize ephemeral associations between meaningless shapes and nonwords, with stimuli presented in either fixed or variable spatial locations, and in either fixed or variable temporal order across trials; performance was assessed using a recognition task. Results showed that children with dyslexia have a deficit in visual–phonological WM binding in every presentation condition and that, unlike control children, they are not able to use fixed spatial locations as an aid to bind information. Crucially, however, children with dyslexia still benefit from the presentation of stimuli in a fixed temporal order. These findings support the hypothesis that a WM binding deficit is crucial in children with dyslexia, and have potential implications for treatment strategies.