Making student thinking about trophic relationships visible through classroom conversations in a general biology laboratory course
Biology laboratory teaching assistants (TAs) represent a unique group of novice teachers because they have little formal teacher preparation and, yet, they are increasingly responsible for implementing student-centered laboratory instruction. A critical component of student-centered instruction involves orchestrating classroom conversations to make student thinking visible and engage students in authentic scientific discourse. Facilitating classroom conversation is especially difficult for novice teachers, and variation in how different TAs implement student-centered instruction can result in different learning experiences for students enrolled in separate sections of the same course. The goal of this study was to describe how three different biology laboratory TAs orchestrated a whole class conversation to explore student ideas about ecological interactions. Each TA was videotaped teaching the same lesson in two different sections of a biology laboratory course for non-science majors. Using the conventions of conversation analysis, we analyzed each conversation to quantify the number and order of TA and student speaking turns, open-ended versus focused questions, wait time, interruptions, questions that focused on student ideas rather than on one correct answer, and pressing for evidence and explanations. These elements were compared both between the three TAs (Jess, Katie, and Caroline) and within each TA’s two different class sections.
The variation between the TAs was greater than the variation within each TA’s two sections. Jess elicited thinking from 18 students whose responses averaged ten words each. Additionally, the students contributed 40% of the total words spoken. Caroline elicited thinking from three students, averaging four words per turn, and the students contributed to 20% of the conversation. Katie elicited thinking from ten students, averaging two words per turn, and the students spoke 25% of the total words. Jess used several instructional moves that may have contributed to her success. She created a written record of student ideas as they constructed a model of the trophic relationships they observed in a local ecosystem, used student names, focused on student thinking instead of looking for one correct answer, and responded to students by re-voicing their contribution and probing their thinking further. In contrast, Caroline interrupted 45% of student turns and Katie enthusiastically praised a two-word, incomplete thought. This study illustrates how students in the same course experience different learning opportunities depending on TA implementation of the same lesson, which has important implications for the design of TA training to support TAs in developing student-centered practices aligned with research on how people learn.