Diversity and unity of modularity

Since the publication of Fodor's (1983) The Modularity of Mind, there have been quite a few discussions of cognitive modularity among cognitive scientists. Generally, in those discussions, modularity means a property of specialized cognitive processes or a domain-specific body of information. In actuality, scholars understand modularity in many different ways. Different characterizations of modularity and modules were proposed and discussed, but they created misunderstanding and confusion. In this article, I classified and analyzed different approaches to modularity and argued for the unity of modularity. Modularity is a multidimensional property consisting of features from several dimensions specifying different aspects of cognition. Among those, there are core features of modularity, and these core features form a cross-dimensional unity. Despite the diverse and liberal characterizations, modularity contributes to cognitive science because of the unity of the core features.     

转基因技术安全性的生态伦理浅析

以转基因技术为基础的生物技术是本世纪最具影响力的高新技术产业带。转基因技术在农业、食品、医药、环保等方面有广泛应用,它给人类社会的发展带来巨大的经济效益和社会效益的同时,也存在着潜在危险,即有可能影响生态环境,危害人类健康。本文试图从生态伦理的角度来思考转基因技术的安全性问题。     

消化内镜医师培训的现状及计算机模拟训练系统的应用

传统的以患者为基础的消化内镜医师培养模式已不能适应消化内镜的快速发展和病患对内镜操作技术的高要求,通过多媒体和虚拟现实技术建立的计算机辅助的内镜模拟训练系统相对于传统的消化内镜医师培训方式是一个巨大进步,它能帮助初学者较快掌握消化内镜诊疗操作的基本技能,使各级消化内镜培训中心的规范化教学成为可能.但是,模拟内镜训练必须结合实际病例的操作才能巩固从模拟内镜得到的内镜操作技能.本文总结了目前消化内镜医师培训的现状,重点对消化内镜模拟训练系统在内镜医师培训中的作用和存在的问题进行探讨,并提出了自己的观点.     

Numerical approximation abilities correlate with and predict informal but not formal mathematics abilities

Previous research has found a relationship between individual differences in children’s precision when nonverbally approximating quantities and their school mathematics performance. School mathematics performance emerges from both informal (e.g., counting) and formal (e.g., knowledge of mathematics facts) abilities. It remains unknown whether approximation precision relates to both of these types of mathematics abilities. In the current study, we assessed the precision of numerical approximation in 85 3- to 7-year-old children four times over a span of 2 years. In addition, at the final time point, we tested children’s informal and formal mathematics abilities using the Test of Early Mathematics Ability (TEMA-3). We found that children’s numerical approximation precision correlated with and predicted their informal, but not formal, mathematics abilities when controlling for age and IQ. These results add to our growing understanding of the relationship between an unlearned nonsymbolic system of quantity representation and the system of mathematics reasoning that children come to master through instruction.     

Child Care in The Netherlands: Trends in Quality Over the Years 1995-2005

The authors assessed the quality of child care in a representative national sample of 42 child-care centers in the Netherlands and compared it with the quality of care that researchers have found using similar samples in 1995 (M. H. van IJzendoorn, L. W. C. Tavecchio, G. J. J. M. Stams, M. J. E. Verhoeven, & E. J. Reiling, 1998) and 2001 (M. J. J. M. Gevers Deynoot-Schaub & J. M. A. Riksen-Walraven, 2005). In the present study, results showed a low level of overall process quality for the 2005 sample, measured by the Infant/Toddler Environment Rating Scale-Revised (T. Harms, D. Cryer, & R. M. Clifford, 2003) and the Early Childhood Environment Rating Scale-Revised (T. Harms, R. M. Clifford, & D. Cryer, 1998). The present authors found a significant decline in process quality in comparison with the 1995 and 2001 findings. They concluded that, from an international perspective, the Netherlands has lost its leading position in child-care quality compared with that from 10 years ago.     

Strategie Calibration and Spatial Alignment: A Model From Prism Adaptation

Two types of adaptive processes involved in prism adaptation have been identified: slower spatial realignment among the several unique sensorimotor coordinate systems (spatial maps) and faster strategic motor control responses (including skill learning and calibration) to spatial misalignment. One measures the 1st process by assessing the aftereffects of prism exposure, whereas direct effects of the prism during exposure are a measure of the 2nd process. A model is described that relates those adaptive processes and distinguishes between extraordinary alignment and ordinary calibration. A conformal translation algorithm that operates on the hypothesized circuitry is proposed. The authors apply the model to explain the advantage of visual calibration when the limb is seen in the starting position prior to movement initiation. Implications of the model for the use of prism adaptation as a tool for investigation of motor control and learning are discussed.     

Variability and Determinism in Motor Behavior

In investigations into perception-action systems, variability of observable behavior may be considered to (a) interfere with inquiry, (b) be neither detrimental nor particularly useful to inquiry, or (c) play a crucial role in inquiry. The authors underscore recent suggestions that alternative (c) is a preferred strategy for the study of many motor behaviors. In tutorial fashion, the authors review the concepts of variability and determinism with respect to postural and rhythmic movements. Study of the variability of those behaviors has revealed crucial features suggestive of underlying mechanisms and control, such as particular blends of noise and determinism (piecewise determinism). It has also revealed general lessons (for example, more variable does not mean more random and more controllable does not mean more deterministic) that may extend to other classes of perceptual-motor behavior.     

Force Control Is Greater in the Upper Compared With the Lower Extremity

The authors investigated whether force control is similar between the upper and lower limbs and between contractions that involve 1 or 2 joints. Six volunteers (27.5 ± 11.2 years of age) attempted to produce consistent discrete rapid force responses of 30, 60, and 90 N by using 6 different body postures, 3 with the upper and 3 with the lower limb. One of the postures for each limb involved 2 joints. The standard deviation of peak force and impulse (aggregate of the force-time curve) was significantly greater (?25%) for the lower limb than for the upper limb (p < .01). Contractions that involved 1 or 2 joints within a limb had similar variability. Therefore, the upper limb might have better control of force than the lower limb because of its extensive use in fine motor tasks in daily activities.     

Interplay of Biomechanical Constraints and Kinematic Strategies in Selecting Arm Postures

In this study, the authors examined the interplay between biomechanics and control strategies in the resolution of excess degrees of freedom at the joint level. Seven participants made aimed arm movements from 30 starting points and several starting postures to targets. Final arm postures for movements to a target exhibited substantial joint angle variation. Through regression modeling and by comparing observed final arm postures with biomechanically plausible postures, the authors identified 3 kinematic strategies: (a) Maintain deviations from the average angle at the starting point to the joint's final posture; (b) make torso rotations that are a fixed proportion of shoulder rotations; and (c) adopt a characteristic combination of 4 wrist-positioning approaches. The results demonstrated that kinematic strategies can account for substantial variance in final arm postures, if one takes into account 2 types of individual differences—those that arise inevitably from biomechanical constraints and those that reflect choices in movement strategy.