ABSTRACT
Perceptual activities, in their various forms and at their various levels of development, thus seem, in principle, to lead to advances in the structuring of perception (decentration) with age. However, because of the new relationships which they entail, they also lead to fresh deformations which derive from the recentrations demanded by those new relationships. It also seems that perceptual activities occur at every age (but, of course, in different forms according to the level involved) and that field effects are merely the by-products of these activities once they have become automatic (field effects having an influence on both deformations and structurings).
