Students' Visualization of Diagrams Representing the Human Circulatory System: The use of spatial isomorphism and representational conventions

Abstract

This study investigated students' interpretation of diagrams representing the human circulatory system. We conducted an interview study with three students aged 14–15 (Year 10) who were studying biology in a Hong Kong school. During the interviews, students were asked to interpret diagrams and relationships between diagrams that represented aspects of the circulatory system. All diagrams used in the interviews had been used by their teacher when teaching the topic. Students' interpretations were expressed by their verbal response and their drawing. Dual coding theory was used to interpret students' responses. There was evidence that one student relied on verbal recall as a strategy in interpreting diagrams. It was found that students might have relied unduly on similarities in spatial features, rather than on deeper meanings represented by conventions, of diagrams when they associated diagrams that represented different aspects of the circulatory system. A pattern of students' understanding of structure–behaviour–function relationship of the biological system was observed. This study suggests the importance of a consistent diagrammatic and verbal representation in communicating scientific ideas. Implications for teaching practice that facilitates learning with diagrams and address students' undue focus on spatial features of diagrams are discussed.

Keywords:

• Diagrammatic representation
• Dual coding theory
• Structure–behaviour–function understanding
• Visualization

Notes

1. In Hong Kong, some schools use Chinese language as the medium of instruction; other schools use English. Therefore, there are two versions of the same set of textbooks in the market. Their contents are equivalent; only that, one is in Chinese language, and the other is in English. This diagram was obtained from the English version of the textbook that students used. The first author has checked that the annotations and the captions to the diagrams in both Chinese and English versions have equivalent meanings.

2. Biologically, the function of capillaries is to facilitate exchanges of materials. Based on the drawing, the student seemed to have missed an important structural–functional relationship of capillaries. However, the discussion here will not go into the ‘misconception’ the student might have.