Moyer MST: Understanding of stem cells

Jon Moyer
A comparative study of how high school students understand stem cells
Unpublished M.S.T. thesis, May 2007

In Spring 2004 an inquiry-based unit on stem cells was developed from chromatin dynamics research at the Jackson Laboratory in Bar Harbor, Maine. The unit was developed according to the backwards design model of curriculum development and implemented in Bangor area high schools in April 2005 and June 2005. With slight modifications, the stem cell unit was re-implemented in June 2006 and tested against a traditional, lecture-based unit.

Open response pre- and post-tests were used to capture initial student conceptions and measure learning gains. Pre-instruction interviews were conducted in order to gain a deeper understanding of pre-test answers. In addition, a two-tailed matched-pair analysis of post-test answers was performed in order to determine the effectiveness of inquiry- based instruction versus lecture-based instruction.

Comparison of pre- and post-tests shows relatively large learning gains after instruction. Analysis of pre-test responses and interview transcripts reveals many misconceptions, such as a fairly widespread belief that abortions are done specifically to obtain stem cells and beliefs that the amount of genetic information of stem cells is different from differentiated cells. Other findings include how students use a variety of terms to describe differentiation and the belief that stem cells are more prevalent early in life and “used up” during development.

The results of the two-tailed, matched-pair analysis for the most part do not indicate statistically significant differences between inquiry- and lecture-based instruction. However, results for a question on controversial aspects of stem cell research imply that the lecture-based instruction was more effective than the inquiry-based instruction at helping students understand the controversy. This result suggests that, given the limited time span of the unit, inquiry-based methods by themselves may not be the most appropriate pedagogy for teaching about controversies in stem cell research. A combination of lecture and inquiry, where the instructor gives a small series of initial lectures before assigning students a genuine inquiry activity, may be a better approach.