Visual representations in the construction of mathematical meanings 1

The impact on the teaching and learning processes of the use of material instruments is the focus of the educational research carried out by our group. The parallel issue concerning the use of ‘virtual’ objects (also much cheaper and easier to distribute to distant locations) included in multimedia is now being studied by educators, who already have some results on the condition of functioning in the classroom. A special issue of Learning and Instruction 13 (2003, 117-254) has been devoted to this question. In the introduction of the topic, the editors Schnotz and Lowe emphasise that multimedia resources can be considered at three levels: the technological level (i.e. software features), the semiotic level (referred to the representation format) and the sensory level (i.e. visual or auditory modality). With regard to these three levels, the authors have found some misconceptions among educators because of a failure to distinguish them. One of these misconceptions is that the technical medium is only level to be considered and it is presumed to have an impact on learning. The authors suggest that: “