ABSTRACT
In 1942 there was published in the 'Archives de Psychologie' a research paper on the Delboeuf illusion by Piaget and his colleagues Lambercier, Boesch and von Albertini. This was the first in a series of some fifty articles in that journal published during a period of over thirty years entitled 'Recherches sur le Développement des Perceptions'. The results of these researches in so far as they contributed to a detailed theory of perception in relation to Piaget's theories concerning the development of knowledge and intelligence were published in 1961 in a book called 'Les Mécanismes Perceptifs', first published in an English translation in 1969 under the title, 'The Mechanisms of Perception' (Piaget, 1969). This book included researches as yet unpublished in the 'Archives de Psychologie', but since then there has been some further work reported in that journal, as well as work related to Piaget's theory published in other journals. In this chapter however I shall confine myself to Piaget's book, because it constitutes a detailed description of his theory, and his theory is what I am interested in.
