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It seems like a no-brainer. If we want to reverse our students’ stagnation in international science tests then some argue that we need to transform the way that we teach science. Instead of boring, teacher-dominated forms of instruction where students are expected to passively absorb facts, they suggest that we need to engage students in what real scientists do: Students should be working in groups, formulating their own hypotheses, discussing the science and carrying out investigations. In this vision, the teacher is a guide-at-the-side who is there to ensure that students have the right resources and don’t go off track. This approach is generally described as ‘inquiry learning’.
It doesn’t work
Unfortunately, the evidence to support inquiry learning is underwhelming. Approaches that have low levels of teacher guidance have repeatedly failed. Those where the amount of guidance is increased have more supporting evidence but, even then, under the favourable conditions of a research study, the effects are small.
Now, we have new evidence from the Programme for International Student Assessment (PISA) results for 2015. These are no experimental results and so we have to treat them with caution. Yet they do offer the chance of investigating inquiry learning in the wild and the results are striking. An increase in the amount of inquiry learning that students report being exposed to is associated with a decrease in science scores. On the other hand, an increase in traditional teacher-directed instruction is associated with an increase in these scores. What’s going on?
Schoolkids not scientists
Firstly, it is worth examining a couple of assumptions. The model of inquiry learning is based upon the idea that the best way of learning science is by behaving like a professional scientist. This is not necessarily true.
The second assumption is that inquiry is more engaging for students. However, it’s not clear that an investigation into which paper towel absorbs the most water is more interesting than a whole class discussion of the fate of the dinosaurs. Even if it were, how can we be sure that short-term interest in a particular activity will translate into a long-term love of the subject? A key driver of long-term motivation seems to be getting better at something. So we want to choose teaching styles that ensure students learn lots.
The cognitive science
If we consider how the brain works then we see a potential problem with inquiry learning. Students are novices who do not know a great deal of science. This means that they need to process everything in a very limited working memory that quickly becomes overloaded. When a professional scientist formulates a hypothesis, she has lots of background knowledge that she can draw upon. High school kids do not have this knowledge and this is likely to send them down a few dead ends – they might even learn the wrong things. Even if they manage to complete an investigation, there will be little cognitive capacity left over to learn from this process.
Teacher-directed instruction is effective because students don’t have to think about lots of things at once. Instead, the teacher can fully guide them through the important concepts and features and ask lots of questions to ensure that these have sunk in.
Ban the Bunsen burners?
This does not mean we should ban practical work or small group discussion or never allow students the opportunity to formulate their own questions; all hallmarks of the inquiry method. Science lesson would be dull if they consisted of the same thing all the time. There is cultural value in conducting scientific experiments at school and this needs to be retained.
What is clear is that we should not be basing science teaching on inquiry methods. Students need expert science teachers who spend a considerable amount of time explaining scientific concepts to them. This might not look very sexy but it is supported by the evidence and our knowledge of cognitive science.