Effects of contiguity, regularity, and age on children's causal inferences.

Investigated the effects of contiguity and regularity on the causal inferences of 96 5- and 6-yr-old and 8- and 9-yr-old children, using a discrimination task whose novelty precluded any reliance on previously gathered information; responses were thus solely a product of the children's firsthand evaluation of the data. Contiguity affected the causal statements of those in each age group, while regularity influenced the statements of the older but not the younger children. Results are basically consistent with Piagetian theory, although several other explanations are viable. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Playing linear number board games—but not circular ones—improves low-income preschoolers’ numerical understanding.

A theoretical analysis of the development of numerical representations indicated that playing linear number board games should enhance preschoolers’ numerical knowledge and ability to acquire new numerical knowledge. The effect on knowledge of numerical magnitudes was predicted to be larger when the game was played with a linear board than with a circular board because of a more direct mapping between the linear board and the desired mental representation. As predicted, playing the linear board game for roughly 1 hr increased low-income preschoolers’ proficiency on the 2 tasks that directly measured understanding of numerical magnitudes—numerical magnitude comparison and number line estimation—more than playing the game with a circular board or engaging in other numerical activities. Also as predicted, children who had played the linear number board game generated more correct answers and better quality errors in response to subsequent training on arithmetic problems, a task hypothesized to be influenced by knowledge of numerical magnitudes. Thus, playing linear number board games not only increases preschoolers’ numerical knowledge but also helps them learn from future numerical experiences. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A comparison of the geometric reasoning of students attending Israeli ultraorthodox and mainstream schools.

Effects of schooling on a geometric misconception were examined by comparing the performance of Israeli students attending ultraorthodox schools with that of peers attending mainstream schools. These groups were of special interest because both value education highly and send essentially all children to school, but 1 group receives extensive instruction in mathematics and science and the other receives almost none. Despite the ultraorthodox 12–14 yr olds' having received no instruction in geometry, they more often solved the geometric misconception problems than did mainstream peers who had received extensive instruction in the subject. Mainstream 16–18 yr olds did somewhat better on the misconception task than did orthodox age peers, but even there, the advantage of the mainstream students was limited to those exposed to the most advanced mathematics curriculum. How mainstream and orthodox schooling may have contributed to these findings is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Aspartame in conjunction with carbohydrate reduces insulin levels during endurance exercise

Background

As most sport drinks contain some form of non-nutritive sweetener (e.g. aspartame), and with the variation in blood glucose regulation and insulin secretion reportedly associated with aspartame, a further understanding of the effects on insulin and blood glucose regulation during exercise is warranted. Therefore, the aim of this preliminary study was to profile the insulin and blood glucose responses in healthy individuals after aspartame and carbohydrate ingestion during rest and exercise.

Findings

Each participant completed four trials under the same conditions (45?min rest?+?60?min self-paced intense exercise) differing only in their fluid intake: 1) carbohydrate (2% maltodextrin and 5% sucrose (C)); 2) 0.04% aspartame with 2% maltodextrin and 5% sucrose (CA)); 3) water (W); and 4) aspartame (0.04% aspartame with 2% maltodextrin (A)). Insulin levels dropped significantly for CA versus C alone (43%) between pre-exercise and 30?min, while W and A insulin levels did not differ between these time points.

Conclusions

Aspartame with carbohydrate significantly lowered insulin levels during exercise versus carbohydrate alone.     

"Hey, would you like a nice cold cup of lemonade on this hot day": Children's understanding of economic causation.

Three experiments were performed to examine development of understanding of functional relations in economics by children between ages 4 and 10 years. Results of Experiment 1 indicated that preschoolers understood the effects of demand, and 2nd graders also understood the effects of supply, but even 4th graders often failed to demonstrate understanding of the effects of motivation and morality. In Experiment 2, 4th but not 2nd graders proved able to explain how motivation and morality might influence sales when told that these variables had an effect. In Experiment 3, 2nd and 4th graders' evaluations of the plausibility of other children's explanations of effects of motivation and morality showed evidence of understanding, though those of kindergartners did not. The data supported the 3 hypotheses that motivated the experiments: (a) direct links between causes and effects are understood before indirect ones, (b) positive correlations between causes and effects are understood before negative ones, and (c) variables that produce effects are understood before ones that do not. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Constraints on learning in nonprivileged domains

Constraints on learning, rather than being unique to evolutionarily privileged domains, may operate in nonprivileged domains as well. Understanding of the goals that strategies must meet seems to play an especially important role in these domains in constraining the strategies that are generated and in allowing children to evaluate strategies even before they use them. The present experiments showed that children can use their conceptual understanding to accurately evaluate strategies that they not only do not yet use but that are more conceptually advanced than the strategies they do use. In Experiment 1, 5-year-olds who did not yet use the min strategy for adding numbers judged it to be smarter than an equally novel illegitimate strategy, and to be just as smart as their typical strategy of counting from one. In Experiment 2, 9-year-olds who did not yet use the forking strategy to play tic-tac-toe judged it to be even smarter than their own win/block approach. The results demonstrated a large number of commonalities between the functioning of constraints in privileged and nonprivileged domains, as well as suggesting some possible differences.     

Plasma prostaglandin E concentrations from birth through childhood

The prostaglandins are synthesized in a variety of tissues and participate in an extensive number of physiologic processes. As prostaglandin concentrations have not been reported in infants and children, we measured PGE levels from birth through childhood. PGE levels in cord blood were significantly higher than those in adults. By 48 to 72 hours of age, however, they had fallen to levels that were significantly lower than those in adults. Although PGE concentrations increased with age, they remained significantly lower than did adult levels. These low levels may be related to some of the functional pecularities of the immature kidney.     

An automated neck flexibility tester

We investigate automation and control options for the neck flexibility tester (NFT) (P. McClure et al., 1998), a device originally used to measure the flexibility of the human cervical spine. The motivation is to lay the foundations for design and implementation of investigative devices that would allow studies of mechanical properties of the spine under repetitive dynamic loading. We derive the equations of motion for an automated NFT (ANFT) using a Lagrangian formulation. These equations, which represent a simplified first-order model of the dynamics, are used to simulate the ANFT using the software package Simulink. Two control schemes are examined: proportional plus integral plus derivative (PID) control and dynamic inversion. Both are simulated for setpoint and tracking control. It appears that PID control is preferred due to its simplicity of design and relative insensitivity to the dynamic model of the ANFT.