Human children 18-24 months of age and 3 young chimpanzees interacted in 4 cooperative activities with a human adult partner. The human children successfully participated in cooperative problem-solving activities and social games, whereas the chimpanzees were uninterested in the social games. As an experimental manipulation, in each task the adult…

In this paper we describe an ontological and semiotic model for mathematical knowledge, using elementary combinatorics as an example. We then apply this model to analyze the solving process of some combinatorial problems by students with high mathematical training, and show its utility in providing a semiotic explanation for the difficulty of…

Math-education reformers encourage the incorporation of mathematical modeling activities into K-12 curricula. Many of the purported educational benefits derive from the authenticity of the activities-how well they reflect the everyday and occupational mathematical practices of adults. But a paucity in the literature of observational descriptions…

This brief article describes how classroom group time can be "talk central" for children to discuss problems, imagine solutions, even role-play hypothetical situations. It is often in the safety and support of the large group that children develop the tools they need to learn how to resolve the inevitable conflicts that arise throughout life.…

One of the most important review topics the author teaches in middle school is the use of metric measurement for problem solving and inquiry. For many years, she had students measuring various objects around the room using the tools of metric measurement. She dutifully taught hypothesizing, data collecting, and drawing conclusions. It was…

From the start of the year, the author's goal is to teach his students to be metacognitive thinkers. This means that they will think about what they are doing during each step of the inquiry process. The author uses a variety of methods to enculturate students into using the thinking processes and developing the dispositions necessary for them to…

The Framework for School Leadership Accomplishments (FSLA) is designed to facilitate thinking about, developing, and implementing school outcomes that improve student learning. The FSLA at once provides a means to organize knowledge in educational administration, an approach to practice that frames what schools can do to improve student learning,…

In university mathematics courses, the activity of proof construction can be viewed as a problem-solving task in which the prover is asked to form a logical justification demonstrating that a given statement must be true. The purposes of this paper are to describe some of the different types of reasoning and problem-solving processes used by…

The efficiency of infants' actions was observed as they picked up and used food-laden spoons that varied in orientation. Two interventions were designed to facilitate efficient action beyond when infants were presented with one spoon in alternating orientations: one spoon was presented in the same orientation for several consecutive trials to help…

This paper develops a mathematical model for the nonselective harvesting of a prey-predator system in which both the prey and the predator obey the Gompertz law of growth and some prey avoid predation by hiding. The steady states of the system are determined, and the dynamical behaviour of both species is examined. The possibility of existence of…

A simple car following model based on the solution of coupled ordinary differential equations is considered. The model is solved using Euler's method and this method of solution is itself interpreted as a mathematical model for car following. Examples of possible classroom use are given. (Contains 6 figures.)

Sexual minority youth are among those most likely to report suicidal thoughts, plans, and attempts (suicidality). This article reviews suicidality risk factors among sexual minority youth, considering both that are common to all youth as well as factors unique to these young people. (Contains 1 figure and 1 table.)

This article illustrates the fact that unless tempered by algebraic reasoning, a graphing calculator can lead one to erroneous conclusions. It also demonstrates that some problems can be solved by combining technology with algebra.

In a 2-phase study with a total of 392 participants, depressive symptoms mediated the association between disordered eating and lower problem-solving confidence and an avoidance problem-solving style. Depressive symptoms did not mediate the association between the ability to generate competent solutions to hypothetical stressful situations and…

The association between nonverbal requesting (as measured by the Early Social Communication Scales) and problem-solving skills (as measured by an object retrieval task) was examined in 16 toddlers who had Down syndrome, 18 toddlers with developmental disabilities of mixed etiologies, and 19 typically developing infants and toddlers. Toddlers with…