Teacher-student co-construction processes in biology: Strategies for developing mental models in large group discussions
The aim of this study was to describe co-construction processes in large group discussions. Co-construction, as used here, is a process by which the teacher and the students work together to construct and evaluate mental models of a target concept. Data were collected for an in-depth case study of a single teacher instructing middle school students with an innovative curriculum on human respiration. Data came from transcripts of video taped lessons, drawings, and pre- and post-test scores. Quantitative and qualitative analyses were conducted. In the quantitative analysis, differences in gains between one and two standard deviations in size were found between the pre- and post-test scores indicating that the students increased their understanding about human respiration. In the qualitative analysis, a generative exploratory method followed by a convergent coded method was conducted to examine teacher-student interaction patterns. The aim of this part was to determine how learning occurred by attempting to connect dialogue patterns with underlying cognitive processes. The main outcome of the study is a hypothesized model containing four layers of nested teaching strategies. Listed from large to small time scales these are: the Macro Cycle, the Co-construction Modes, the Micro Cycle, and the Teaching Tactics. The most intensive analysis focused on identifying and articulating the Co-construction Modes—Accretion Mode, Disconfirmation Mode, Modification Mode, Evolution Mode, and Competition Mode—and their relations to the other levels of the model. These modes can either describe the construction and evaluation of individual model elements or of entire models giving a total of ten modes. The frequency of these co-construction modes was then determined by coding, twenty-six hours of transcripts. The most frequent modes were the Accretion Mode and the Disconfirmation Mode. The teacher's and the students' contributions to the co-construction process were also examined. It was found that both the teacher and the students generated ideas in approximately equal proportion to build the models, that the teacher usually evaluated the ideas, and that both modified or disconfirmed the ideas. Thus the study is an attempt to develop a vocabulary for describing strategies that facilitate student model construction.