A Word is Worth a Thousand Pictures: A Systemic Functional and Multimodal Discourse Analysis of Intersemiotic Evaluation in University Science Textbooks.

摘要

Images are an invaluable medium in science textbooks for clarifying confusing concepts and establishing a visual foundation for field related topics. The integration of image and language within a single unit of discourse builds a larger meaning than the two semiotic forms are capable of producing separately. Visual representations are chosen for their functional value in aiding linguistic explanation and also for their aesthetic value in textual enhancement. Aesthetic choice is a matter of subjective opinion. Although science writing is generally classified as objective, authors embed personal opinion in written and visual discourse. The choice of visual medium has a profound effect on the author's linguistic choices, which manipulates the reader's interpretation of discourse. Through the application of the Systemic Functional Linguistic framework in conjunction with Systemic Functional Multimodal Discourse Analysis to university undergraduate level science textbooks, analysis indicates that not only do science textbook authors use images to evaluate in-text subjects, but also to reference images with heightened subjectivity. Findings further demonstrate that science authors use evaluative language to direct reader interpretation of the image using patterns of evaluation which is contingent upon the medium of the image and the functional relationship between image and language.