Heuristics versus direct calculation,and age-related differences in multiplication: an evidence accumulation account of plausibility decisions in arithmetic

We offer a new theoretical angle for cognitive arithmetic, which is that evidence accumulation may play a role in problem plausibility decisions. We build upon previous studies that have considered such a hypothesis, and here formally evaluate the paradigm. We develop the finding that performance differences, due to variations in strategy use and aging effects, can indeed be reasonably explained through these accumulation-to-bound cognitive models. Results suggest that these models may be effectively used to learn more about the underlying cognitive processes. In this study, we modelled young (18–24) and older (68–82) adults’ solution times in performing arithmetic verification (e.g. whether 8?×?5?=?41 is true/false). The domain-relevant factors in strategy use (problem-verification heuristics) and aging differences (older/younger adult groups) were analyzed by a response process model of the latency data, that is fit by participant and item. Lower thresholds accounted for the faster response times (RTs) for problems solved with heuristics (arithmetic rule-violation checking strategies), as opposed to problems solved by calculation approaches. A more rapid accumulation accounted for faster RTs on problems in which two arithmetic rules were violated (strategy combination) rather than one. Third, higher thresholds (i.e. preferring to have greater certainty before responding) accounted for older adults’ slower speed. These findings are in support of accumulation models being relevant for more complex cognitive tasks, as well as to account for the age-related differences therein.     

Rate of Torque Development and Feedforward Control of the Hip and Knee Extensors: Gender Differences

The purpose of this study was to determine whether women demonstrate decreased rate of torque development (RTD) of the hip and knee extensors and altered onset timing of the vastus lateralis and gluteus maximus during a drop-jump task when compared with men. On average, women demonstrated significantly lower normalized RTD of the hip extensors (women: 11.6 ± 1.3 MVT.s^?1, men: 13.1 ± 0.9 MVT.s^?1; p ≤ .01); however, there was no significant difference in knee extensor RTD. Women also demonstrated significantly earlier activation of their vastus lateralis (women: 206.0 ± 130.6 ms, men: 80.9 ± 69.6 ms; p ≤ .01) and gluteus maximus (women: 85.7 ± 58.6 ms, men: 54.5 ± 35.4 ms; p = .02). In both men and women, there was a significant negative correlation between the hip extensor RTD and the vastus lateralis electromyographic onset time (men: r = –.386, p = .046; women: r = –.531, p = .008). The study findings suggest that women may utilize a feedforward control strategy in which they activate their knee extensors earlier than men to compensate for deficits in hip extensor RTD. The impaired capacity to rapidly stabilize the hip and knee joints during dynamic maneuvers may contribute to the increased risk of anterior cruciate ligament injury observed in women.     

乡镇小学生的数学焦虑与数学成绩:数学自我效能感和数学元认知的链式中介作用

采用儿童数学焦虑量表、小学生数学学习自我效能感量表和小学生数学元认知问卷,对508名乡镇中、高年级小学生进行测量,并运用结构方程模型探讨数学焦虑影响数学成绩的内在作用机制。结果发现：（1）数学焦虑显著负向预测数学自我效能感、数学元认知和数学成绩,数学自我效能感显著正向预测数学元认知和数学成绩,数学元认知显著正向预测数学成绩;（2）在数学焦虑对数学成绩的预测中,数学自我效能感和数学元认知均发挥了部分中介作用;（3）数学自我效能感和数学元认知在数学焦虑和数学成绩之间起链式多重中介的作用。因此,数学焦虑除了直接作用于小学生的数学成绩,还可通过数学自我效能感或数学元认知间接影响数学成绩,而且可通过数学自我效能感进而通过数学元认知间接影响数学成绩。文章讨论了上述发现的理论及教育实践含义。     

Higher visuo-Attentional Demands of Multiple Object Tracking (MOT) Lead to A Lower Precision in Pointing Movements

Multiple object tracking (MOT) requires visually attending to dynamically moving targets and distractors. This cognitive ability is based on perceptual-attentional processes that are also involved in goal-directed movements. This study aimed to test the hypothesis that MOT affects the motor performance of aiming movements. Therefore, the participants performed pointing movements using their fingers or a computer mouse that controlled the movements of a cursor directed at the targets in the MOT task. The precision of the pointing movements was measured, and it was predicted that a higher number of targets and distractors in the MOT task would result in a lower pointing precision. The results confirmed this hypothesis, indicating that MOT might influence the performance of motor actions. The potential factors underlying this influence are discussed.     

Extracurricular Participation and Course Performance in the Middle Grades: A Study of Low-Income,Urban Youth

The transition to middle/junior high school is associated with declines in students’ academic performance, especially among low‐income, urban youth. Developmental psychologists posit such declines are due to a poor fit between the needs of early adolescents—industry, identity, and autonomy—and the environment of their new schools. Extracurricular participation during these years may act as a buffer for youth, providing a setting for development outside the classroom. The current study examines participation within and across activity settings among low‐income, urban youth in New York City over this transition. Using the Adolescent Pathways Project data, this study explores how such participation relates to course performance. We find that a large percentage of youth are minimally or uninvolved in extracurricular activities during these years; that participation varies within youth across time; and that the association between participation and course performance varies by activity setting. Youth who participate frequently in community or athletic settings or have high participation in two or more settings are found to have higher GPAs in the year in which they participate and youth who participate frequently in the religious setting are found to have lower GPAs. High participation in more than two settings may be detrimental.     

Qualitative elements of early motor development that influence reaching of the erect posture. A prospective cohort study

The proposed assessment sheet aims to show in detail, which qualitative elements of motor performance are performed correctly in the 2nd month of life by children who in the 9th month reached the erect posture. Similar analysis was performed for the qualitative assessment in the 6th month. The prospective investigation of motor development involved a group of 109 children (40 girls and 69 boys). The study was based on the previously described quantity and quality assessment sheet of motor performance, validated for the 2nd and 6th month. Final investigation took place in the 9th month of life and was based on a neurological assessment.It could be shown that a completely correct assessment at the age of 2 months precludes future severe motor development disorders, especially cerebral palsy, although it does not rule out a slight delay. Prematurity and the analyzed risk factors, particularly IVH, impair the motor performance. The absence of axial symmetry, the shoulders protraction and improper position of the pelvis are the most important alarming features at the 2nd month. Distal elements observed in the prone position at the 6th month show a good prognosis for the motor performance in the 9th month. Any abnormalities, mainly related to the body axis and symmetry observed at 2 months of age should encourage one to put a child under observation.     

Fine and gross motor skills: The effects on skill-focused dual-tasks

Dual-task methodology often directs participants’ attention towards a gross motor skill involved in the execution of a skill, but researchers have not investigated the comparative effects of attention on fine motor skill tasks. Furthermore, there is limited information about participants’ subjective perception of workload with respect to task performance. To examine this, the current study administered the NASA-Task Load Index following a simulated shooting dual-task. The task required participants to stand 15 feet from a projector screen which depicted virtual targets and fire a modified Glock 17 handgun equipped with an infrared laser. Participants performed the primary shooting task alone (control), or were also instructed to focus their attention on a gross motor skill relevant to task execution (gross skill-focused) and a fine motor skill relevant to task execution (fine skill-focused). Results revealed that workload was significantly greater during the fine skill-focused task for both skill levels, but performance was only affected for the lesser-skilled participants. Shooting performance for the lesser-skilled participants was greater during the gross skill-focused condition compared to the fine skill-focused condition. Correlational analyses also demonstrated a significant negative relationship between shooting performance and workload during the gross skill-focused task for the higher-skilled participants. A discussion of the relationship between skill type, workload, skill level, and performance in dual-task paradigms is presented.     

Constrained paths based on the Farey sequence in learning to juggle

In this article we report the results of a study conducted to investigate the learning dynamics of three-ball juggling from the perspective of frequency locking. Based on the Farey sequence, we predicted that four stable coordination patterns, corresponding to dwell ratios of 0.83, 0.75, 0.67, and 0.50, would appear in the learning process. We examined the learning process in terms of task performance, taking into account individual differences in the amount of learning. We observed that the participants acquired individual-specific coordination patterns in a relatively early stage of learning, and that those coordination patterns were preserved in subsequent learning, even though performance in terms of number of successful consecutive throws increased substantially. This increase appeared to be related to a reduction in spatial variability of the juggling movements. Finally, the observed coordination patterns were in agreement with the predicted patterns, with the proviso that the pattern corresponding to a dwell ratio of 0.50 was not realized and only a hint of evidence was found for the dwell ratio of 0.67. This implies that the dwell ratios of 0.83 and 0.75 in particular exhibited a stable coordination structure due to strong frequency locking between the temporal variables of juggling.     

Soldiers Lead Themselves to More Success: A Self-Leadership Intervention Study

Neck and Manz (1999) Neck, C. P., & Manz, C. C. (1999). In search of the self-led soldier: Army leadership in the twenty-first century. In J. G. Hunt, G. E. Dodge, & L. Wong (Eds.), Out of the box leadership: Transforming the twenty-first army and other top organizations (pp. 153–176). Stamford, CT: JAI Press. [Google Scholar] elaborated in their article “In Search of the Self-Lead Soldier” on the need for continuous improvement of personnel qualities such as increase in self-efficacy, increase of performance, and decrease of perceived strain. Self-leadership is a tool that fosters exactly these personal resources. This study examines self-leadership training effects on soldiers participating in a military training course over 14 weeks. It is the first self-leadership training study to evaluate performance improvement using objective criteria (examination marks, physical tests) in intervention and control group consisting of soldiers of the Austrian army. Its design features a large sample (N = 130), duration of self-leadership training over 10 weeks, and evaluation over 4 time points. The intervention group accomplished significantly higher educational achievements in examinations and physical tests. Also levels of self-efficacy were significantly higher and levels of strain were marginally to significantly lower.