When the mental number line involves a delay: the writing of numbers by children of different arithmetical abilities

Our study focused on number transcoding in children. It investigated how 9-year-olds with and without arithmetical disabilities wrote Arabic digits after they had heard them as number words. Planning time before writing each digit was registered. Analyses revealed that the two groups differed not only in arithmetical abilities but also in verbal and reading abilities. Children with arithmetical disabilities were overall slower in planning Arabic digits than were control children with normal arithmetical abilities. In addition, they showed a number size effect for numbers smaller than 10, suggesting a semantically mediated route in number processing. Control children did not need more planning time for large numbers (e.g., 8) than for small numbers (e.g., 3), suggesting a direct nonsemantic route. For both two- and three-digit numbers, both groups of children showed a number size effect, although the effect was smaller each time for control children. The presence of the stronger number size effect for children with arithmetical disabilities was seen as a delay in the development of quick and direct transcoding. The relation between transcoding problems and arithmetical disabilities is discussed. A defect in the linking of numerical symbols to analog numerical representations is proposed as an explanation for the transcoding problems found in some children.     

The aftermath of 9/11: effect of intensity and recency of trauma on outcome

Does trauma exposure have a long-term impact on the brain and behavior of healthy individuals? The authors used functional magnetic resonance imaging to assess the impact of proximity to the disaster of September 11, 2001, on amygdala function in 22 healthy adults. More than three years after the terrorist attacks, bilateral amygdala activity in response to viewing fearful faces compared to calm ones was higher in people who were within 1.5 miles of the World Trade Center on 9/11, relative to those who were living more than 200 miles away (all were living in the New York metropolitan area at time of scan). This activity mediated the relationship between group status and current symptoms of posttraumatic stress disorder. In turn, the effect of group status on both amygdala activation (fearful vs. calm faces) and current symptoms was statistically explained by time since worst trauma in lifetime and intensity of worst trauma, as indicated by reported symptoms at time of the trauma. These data are consistent with a model of heightened amygdala reactivity following high-intensity trauma exposure, with relatively slow recovery.     

A Test and Refinement of the Demand–Control–Support Model in the Construction Industry

This study aims at a test and further refinement of the Demand–Control–Support (DCS) model among construction workers (N = 210). On the basis of theory and empirical evidence, we hypothesized that mental or physical job demands, low job control, and lack of social support at work have direct and synergistic effects on burnout. The model was expanded by hypothesizing that burnout mediates the relationships between these potentially demanding working conditions on the one hand, and health complaints on the other. Results of a series of structural equation analyses partly supported these hypotheses. The proposed model fitted adequately to the data, although some variables in the DCS model did not make a unique contribution to explaining variance in burnout and (indirectly) health complaints. Interestingly, lack of social support was the most important determinant of burnout and health complaints among construction workers. In addition, a significant three-way interaction effect partly confirmed the synergism hypothesis: Physical demands were only related to burnout if participants had poor job control and reported high social support. The implications of these findings for research and practice are discussed.     

Decade breaks in the mental number line? Putting the tens and units back in different bins.

Most models of number recognition agree that among other number representations there is a central semantic magnitude representation which may be conceptualized as a logarithmically compressed mental number line. Whether or not this number line is decomposed into different representations for tens and units is, however, controversial. We investigated this issue in German participants in a magnitude comparison (selection) task in which the larger of two visually presented Arabic two-digit numbers had to be selected. Most importantly, we varied unit-decade-compatibility: a number pair was defined as compatible if the decade magnitude comparison and the unit magnitude comparison of the two numbers would lead to the same response (e.g. 52 and 67) and as incompatible if this was not the case (e.g. 47 and 62). While controlling for overall numerical distance, size and other variables, we consistently found compatibility effects. A control experiment showed that this compatibility effect was not due to perceptual presentation characteristics. We conclude that the idea of one single number line representation that does not additionally assume different magnitude representations for tens and units is not sufficient to account for the data. Finally, we discuss why decade effects were not found in other experimental settings.     

Onset and termination of accessory facial movements during stuttering

In this study the onset and offset times of seven types of accessory facial movements during oral and silent prolongations were described in three severe stutterers. For each observed facial movement the onset and offset times were determined by means of slow motion analysis of video-recorded speech samples. For two of the three subjects significant differences in the onset and offset times at the various facial movements were found; however, no consistent patterns in the separate facial movements could be observed. On the contrary, the onset of most facial movements appeared to be located at the very start and their offset at the end of the stuttering moment. The implications of these findings with respect to the function of accessory facial movements in stuttering are discussed.