Whenever they are immersed in the study of controversial techno-scientific questions, students are confronted by a 'sciencc-in-the-making' (to use Latour's expression (1989))that is, a context in which scientists arc seen not to be in agreement and in which controversies generate uncertainty. How will students react to these situations? What arguments will they devise in order to develop a position? My present research is dedicated to questions such as these. In the view of some researchers, students can be prompted to emphasize values (Fensham, 2002; Fleming. 1986; Grace & Ratcliffe, 2002). For others, the social and epistemological considerations raised by students are the determining factors in the decisions they reach (Aikenhead, 1985; Ryder, 2001). The relationship to risk is also fundamental to students' perspectives on these controversial questions (Kolsto, 2001). Finally, a number of researchers have questioned the worth of using scientific knowledges in decisions regarding socio-scientific issues (Irwin & Wynne, 1996; Kortland, 2001; Lewis, Leach, & Wood-Robinson, 1999; Ratcliffe, 1997; Solomon, 1988; Tytler, Duggan, & Gott. 2001). I have attempted to discern the justifications given by electronics technologies students for their positions concerning the uncertain and controversial issue of the danger posed by cellular telephones. Students' positions were gathered in writing before and after an in-class role-playing exercise that simulated a debate on this issue. A debate about a techno-scientific controversy constitutes an opportunity to question the authority of science, to inquire into the disagreements and different interpretations of phenomena within the scientific community, and to grapple with the uncertainty of unstable knowledges. This debate was staged from the perspective of citizen education in the nature of the sciences, the aim of which is to provide citizens with the education they need to think critically about interactions between science, technologies, and society, as well as to make informed decisions with respect to questions raised by the techno-sciences and their accompanying spillovers. As such, this debate drew on a training module constructed by Hind, Leach, & Ryder (2001a) for the epistemological education of students. The ten student participants were all training to become senior electronics technicians in Tunisia. They played the role of expert witnesses in a lawsuit in which an employee was suing his employer for his poor health, which had forced him to quit his job and which he ascribed to the use of a cellular telephone. The students were divided into two groups to defend the opposing theses that cellular telephones either were or were not dangerous to one's health. They studied seven excerpts from research focusing on the occurrence of disease in animals, epidemiological surveys, and memory tests. Pre-and post-debate questionnaires were used to gather the students' views concerning the danger posed by cellular telephones. For the most part, the students justified their positions on the basis of widespread notions about the effects of microwaves on human health, on the one hand, and on social and epistemological considerations, on the other. Factors weighing in changes in students' opinions about the danger of cellular telephones included the demand for scientific proof, the influence of telephone companies, and disagreements between scientists. Few students, it is clear, drew on the research excerpts studied during the debate exercise and their interpretations differed. The students appeared to have appropriated scientific language; further, the conceptual errors noted prior to the debate were no longer in evidence once it had been completed. Decision making was little influenced by scientific and technological knowledge, while social and epistemological considerations, on the other hand, played a larger role. In response to the uncertainties and lack of consensus surrounding the research findings available to them, students tended to abide by overvalued scientific expertise.
