ABSTRACT
In this contribution we describe the evolution of a field of research in which we have been involved for some 15 years, investigating cognitive and social aspects of mathematics learning. Our aim is not to present a succession of research results but rather the progressive modification of the issue under study. The visible outcome was sometimes answers to the questions raised, but often also of the modification o f the research questions, and as a consequence the search for changes in methods appropriate for their investigation. We will also refer to other work, which is not directly centred on the learning and teaching of mathematics, to which we have contributed and which has played a part in the progress of our studies of children and school mathematics.
