The impact of a prelaboratory discussion on non-biology majors' abilities to plan scientific inquiry

Non-science majors often have difficulty with the task of experimental design. This study addressed the hypothesis that a greater proportion of students in an undergraduate biology laboratory course would be able to plan scientific investigations if they were to discuss their predictions before each investigation. The “prediction discussion” approach engages students in explaining and discussing their scientific ideas. Three abilities for planning investigations were tested in this study: constructing a causal hypothesis; isolating and controlling variables; and the use of appropriate controls in the design of an experimental procedure. Prediction discussion did not help students design better experiments or construct a causal hypothesis. However, more students who participated in prelaboratory prediction discussions were able to isolate and control variables. Reasons for these results are suggested by a detailed look at the errors students made, indicating that students had problems with scientific terms and many were biased by their prior knowledge when considering factors to identify in their experimental designs.