Pierre Mounoud

Conservation of Weight in Infants.

Abstract Conversation of weight can be defined as the ability to affirm that the weight of an object remains invariant during the transformations of the form of the object. It is known to be achieved at a conceptual level at about 9 years of age. The behavior of infants seems to indicate that between 6 and 18 months of age they develop a sensorimotor form of conversation.

Perceptuomotor compatibility in pursuit tracking of two-dimensional movements.

In a previous article, we reported an investigation of visuomanual pursuit tracking of unpredictable two-dimensional targets. This article extends the study to the tracking of predictable stimuli. In both investigations, the target trajectory was elliptical. The experimental factors we varied were the orientation of the major axis of the ellipses (horizontal or vertical), the period of the movement (9.65 to 1.61 s), and the law of motion (natural vs. transformed). In the natural condition (L), the motion results from the combination of harmonic functions, as would be the case if the target were generated by a human. In the transformed (T) condition, the law of motion departs systematically from this natural model. The main results of the study are as follows: (a) Satisfactory performance is achieved only in the natural condition. Pursuit movements obey the same constraints observed in spontaneous movements. (b) Predictability affects significantly the average delay between target and pursuit. (c) Each component of the pursuit movements depends on both components of the targets. Thus, two-dimensional tracking generalizes significantly the classical one-dimensional condition. (d) The simple model developed previously to describe performance with unpredictable targets can be generalized to cover the present case as well.

Effects of lexicality and trigram frequency on handwriting production in children and adults

Recent studies of handwriting have shown that linguistic variables, such as phonology or lexicality, influence various aspects of the production of letter sequences. Following a previous experiment, in which a facilitation effect of words over pseudowords has been documented both in children and in adults, an experiment is reported concerning the effect of lexicality and of trigram frequency on handwriting production at different levels of handwriting mastery. In this experiment, 8- to 12-year-old children and adults were asked to write words, pseudowords ending with a frequent trigram, and pseudowords ending with a nonfrequent trigram. Results show that in adults there is a facilitation effect of words over pseudowords and of frequent trigrams over nonfrequent trigrams. In children, no clear effect of lexicality or trigram frequency could be observed. Developmental trends show that major changes in childrens handwriting occur between 8 and 10 years, whereas only minor modifications are observed between 10 and 12 years.

Motor Strategies in Lifting Movements: A Comparison of Adult and Child Performance

The experiment compares the performances of children six to nine years old and adults in a simple, monoarticular lifting task. Overt behaviors, as described by the kinematic features of the movement, do not differ qualitatively in the two groups. The patterns of motor commands, as expressed by the electromyographic recordings, are however strikingly different. Adults plan the movement with a careful balance between agonist muscle activity and passive, viscoelastic forces, whereas children use both agonist and antagonist active forces. It is argued that the motor strategy adopted by adults depends upon an internal representation of the properties of the motor system and of the size/weight covariation in natural objects, and that this representation is not yet fully developed at nine years of age.

Development of visuomanual tracking in 5- to 9-year-old boys ☆

Abstract Visuomanual sinusoidal tracking is investigated in 5- to 9-year-old children. The proportion of successful performances steadily increases with age, but adult proficiency is never attained even by those who can perform the task. Moreover, the progress in proficiency—as measured by systems analysis techniques—is not monotonic and suggests the presence of distinct stages in the development of visuomotor coordination. Qualitative analysis of unsuccessful performance demonstrates that failures cannot be ascribed only to insufficient motor coordination and emphasizes the role of cognitive and representational factors even in such a simple task.

Contribution of the Priming Paradigm to the Understanding of the Conceptual Developmental Shift from 5 to 9 Years of Age.

We conducted three experiments to study the role of instrumental (e.g. knife-bread) and categorical (e.g. cake-bread) relations in the development of conceptual organization with a priming paradigm, by varying the nature of the task (naming--Experiment 1--or categorical decision--Experiments 2 and 3). The participants were 5-, 7- and 9-year-old children and adults. The results showed that on both types of task, adults and 9-year-old children presented instrumental and categorical priming effects, whereas 5-year-old children presented mainly instrumental priming effects, with categorical effects remaining marginal. Moreover, the magnitude of the instrumental priming effects decreased with age. Finally, the priming effects observed for 7-year-old children depended on the task, especially for the categorical effects. The theoretical implications of these results for our understanding of conceptual reorganization from 5 to 9 years of age are discussed.

The emergence of new skills : dialectic relations between knowledge systems

Abstract At the beginning of every learning or developmental process behaviors can be described as determined simultaneously by two different knowledge systems. A rather achieved and automatized system integrating a large amount of information in a ‘direct’ way (bottum-up) reveals itself in practical forms of knowledge. Another system in elaboration reveals itself in conceptual forms which select and reinterpret subsamples of information that are relevant regarding the pursued goals. These two systems maintain hierarchical and fairly complex relations which reverse over time: The conceptual forms produced by the new knowledge system are initially directed or framed by the practical forms of the previous system, but finally end up controlling and integrating them. The term practical is attributed to every automatized behavior (material or mental) for which all the previous cognitive activities having constituted it are not accessible or explicitable anymore.

On the Relevance of Piaget's Theory to the Visual Arts

Piagets genetic epistemology [1], which treats of the formation and evolution of science, is based on the parallelism between the historic development of science and the development of intelligence in children. This parallelism reveals the mechanism common to these developments and thereby sheds a new light on the evolution of scientific concepts and theories. It is tempting to search in the same manner for a parallel between the evolution of an artist, and even between the progression of a work of art while it is being made, and the evolution of the way children represent the world of objects. If one attempts to make such a parallel, one must take heed that whereas children tend to progress in their knowledge and understanding of the outside world, and in their ability to act on it (a definition that can apply also to the activity of scientists), the aims of artists are difficult to define in a general manner. In this note, therefore, we shall restrict ourselves to endeavours of artists and of children that can be compared, and we will find that similar mechanisms underly their progress. We first must give some general considerations that are fundamental to Piagets theory and that apply to an artists work, just as they are known to apply to the way in which children or scientists proceed. These considerations shed a new light on the way artists proceed by placing their procedure in a framework different from that of aesthetics. We then go on to show some specific analogies between the mechanism governing the creation of a work of art or, more precisely, of representational art and the mechanism governing the manner in which children represent objects. In the execution of a work of art, an artist engages in a struggle comparable to that of a child when its means of understanding develops during the course of its activities. The execution of a work of art by an artist, like the construction of reality by a child, can be characterized by an adaptive and evolutive process that goes on until a temporary state of

Development of Motor Control in the Child: Theoretical and Experimental Approaches

This chapter is concerned with some general aspects of the ontogenetic development of motor planning and control in the child. According to classical theories on human development, psychologists describe the age of 2 years as a transition between two main steps in child development. However, this age can in no case be considered as an “endpoint” in the perceptuomotor development, nor as a “startingpoint.”

A Point of View on Ontogeny.

A contradiction arises from the transposition by Piaget of the phylogenetic problem of the appearance of new forms to the ontogeny of knowledge. Whereas Piaget ex