Working with artefacts: the potential of gestures as generalization devices

The paper will summarize the work of the Modena team on gestures. Such studies draw on the classical analysis of the shift from grasping to pointing in the social interaction of the pair baby-mother. We have studied the essential function of gesturing in classroom situations for the construction of scientific meanings and processes. In particular, in our previous papers concerning experiments in grades 4 and 5, we have focused the generalising potential of gesturing (in contrast with other iconic representation media, which, rather, risk to fix the particular emergences of phenomena). In the former we have studied the genesis of a germ theory of the functioning of gears, from gestures to arrows and to general, abstract and conditional statements. In the latter we have studied the construction of the meaning of painting as the intersection between a plane (the picture plane) and the visual pyramid as meant by the early theoreticians of perspective drawing, by means of ‘cutting’ gestures that mime in the space the intersection of an ideal solid, in situations of social interaction. Our results are consistent with the findings of Roth & Lawless who claim that “in terms of conceptual development, gestures express features of scientific concepts and relations prior to the equivalent representation in verbal discourse. That is, gestures appear to scaffold the emergence of students’ observational and theoretical language about the phenomena they study".