How do we know he is not talking about himself? Demonstrations in Science Classroom Lilian Pozzer-Ardenghi a,1, * , Wolff-Michael Roth b,2 a University of Victoria, Faculty of Education, Department of Curriculum and Instruction, Chat@UVic Research Group, MacLaurin Building A420, PO Box 3100 STN CSC, Victoria, BC, Canada V8W 3N4 b University of Victoria, Faculty of Education, Department of Curriculum and Instruction, Lansdowne Professor Applied Cognitive Science, MacLaurin Building A548, PO Box 3100 STN CSC, Victoria, BC, Canada V8W 3N4 Received 29 November 2005; received in revised form 4 November 2008; accepted 9 November 2008 Abstract Although the development of the sciences was mediated in crucial ways by the development of visual representations, language continues to be treated as the dominant representational mode in science teaching. In this study, we focus on instances where demonstrations occur, in which self-references are to be understood as references in general, and investigate the semiotic resources provided by the lecturer to disambiguate references from self-references. Our data corpus is derived from a 3-month study of twelfth-grade biology lessons in human anatomy and physiology. We analyzed all those instances where the lecturer makes reference to someone else in his speech but gestures with or points to his own body. We describe the different resources (markers) used to disambiguate the conflation of self-reference and reference and theorize the phenomenon by building on a dialectical framework for understanding communication. # 2008 Elsevier B.V. All rights reserved. Keywords: Demonstrations; Verbal and nonverbal markers; Communication; Gestures; Reference and self-reference; Science teaching; Dialectical unit 1. Introduction In everyday conversation, people make reference to places, objects, other people, and time. They also refer to themselves and to the direct interlocutor(s) during the conversation. Besides verbal reference—achieved through using pronouns such as ‘I’ and ‘you’—and demonstrative terms (e.g., ‘this’ and ‘there’), one can also use gestures to refer or point to something. In fact, gestures may contribute to disambiguate crucial aspects that help us to understand what the person is trying to communicate (e.g., Roth and Lawless, 2002; Roth and Pozzer-Ardenghi, 2006). Another way through which reference can be made is in the form of a demonstration, 3 when a person speaking performs and www.elsevier.com/locate/pragma Available online at www.sciencedirect.com Journal of Pragmatics 41 (2009) 684–698 * Corresponding author. Present address: Department of Integrated Studies in Education, Faculty of Education, McGill University, 3700 McTavish Street, Montreal, QC, Canada H3A 1Y2. Tel.: +1 514 398 2462; fax: +1 514 398 4529. E-mail addresses: lilian.ardenghi@mcgill.ca (L. Pozzer-Ardenghi), mroth@uvic.ca (W.-M. Roth). 1 Tel.: +1 250 398 2462. 2 Tel.: +1 250 721 7885; fax: +1 250 721 7598. 3 We use the following definition of demonstration: a show or display; the act of presenting something to sight or view (Source: WordNet 1 2.0, # 2003 Princeton University). 0378-2166/$ – see front matter # 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.pragma.2008.11.002