  The framing of issues in the mass media plays a crucial role in the public
understanding of science and technology. This article contributes to research
concerned with diachronic analysis of media frames by making an analytical
distinction between implicit and explicit media frames, and by introducing an
automated method for analysing diachronic changes of implicit frames. In
particular, we apply a semantic maps method to a case study on the newspaper
debate about artificial sweeteners, published in The New York Times (NYT)
between 1980 and 2006. Our results show that the analysis of semantic changes
enables us to filter out the dynamics of implicit frames, and to detect
emerging metaphors in public debates. Theoretically, we discuss the relation
between implicit frames in public debates and codification of information in
scientific discourses, and suggest further avenues for research interested in
the automated analysis of frame changes and trends in public debates.
