In this back-to-school period, I decided to talk to you about the science of teaching, and the teaching of science! Oh, don’t worry, I’m not going to try to explain to teachers how they should do their job in general, but rather talk about a specific debate that I didn’t know had been the subject of many publications: the benefits of active learning .
In this post, we will see why it seems obvious that active pedagogy is much better than traditional teaching methods, and why in the end it may not be so sure!
Let’s do a thought experiment: you are a college physics teacher. You need to teach your students about falling bodies, including the fact that – in a vacuum – all bodies fall the same way, regardless of their mass or nature .
You are given the choice between two methods:
A so-called direct instruction method : you have your students take a notebook and a pen, you grab your chalk, and you solemnly write on the board “In a vacuum, all bodies fall in the same way with an acceleration equal to that of gravity. g = 9.8m/s2”. You repeat, you frame in red and you ask them to learn it well by heart.
A so-called “active” method : you form small groups and ask your students what they think of falling bodies. Then you have them experiment with falling into a tube in which you can evacuate and drop objects. They experiment with various objects (a feather, a coin) and time the trajectories in the tube. And they themselves arrive at the conclusion of an identical fall with constant acceleration, while being marked by the spectacular behavior of the feather falling into the void
For many, it is obvious that the second method is much better for learning and understanding. Besides, as Confucius said (it’s always classy to quote Confucius):
confucius_jean_piagetWhat Confucius summarizes in a clear way became a theory of pedagogy, which appeared in the 20th century under the term constructivism . Its essential idea is that learning is an active process: one retains and better understands the knowledge that one has constructed oneself , that one has discovered, as opposed to that which one has received “all cooked”.
Since we are in quotations, Jean Piaget (opposite next to Confucius), one of the founding fathers of constructivism told us:
If we follow the constructivist idea, it would therefore be more effective to learn (and therefore to teach) through practical activities, games and group discussions, than through a lecture, a book or a presentation.
From the idea of constructivism, several variants of active pedagogy have been developed, but they all revolve more or less around the same ingredients found in what has been called “problem-based learning”.
The idea is to start from a problem situated in its context, and not necessarily “well-posed” (for example “How fast do objects fall?”). Working in a group makes it possible to analyze the problem, to mobilize previous knowledge and to try to formulate hypotheses and strategies to solve it. And it is by solving the problem that one builds oneself the new knowledge to be acquired .
Of course in this type of pedagogy, the role of the teacher changes, since he is no longer there to deliver knowledge, but rather to facilitate its discovery by the students.
Problem-based learning applies particularly well to science, as in the example I cited at the beginning of this post. Through practical work or scientific projects, students can construct the knowledge they need to acquire themselves, by reproducing the path taken by professional researchers to make their discoveries.
(By the way, I often had the impression in my schooling that scientific practical work – from 2nd to university – was closer to direct instruction than to active pedagogy, with very directed statements like “do this and watch that”, and leaving little room for exploration).
Active learning, does it really work?
child sleeping in classAccording to proponents of this method of teaching, active methods improve students’ understanding, memorization and ability to solve problems, as well as their motivation to learn and work in groups. In short, that’s good.
It seems clear, and yet … this belief is based mainly on intuition, but not very much on in-depth studies! First, it is obvious that in some areas, direct instruction is much more effective than the active method . I doubt you would want to learn to fly an airplane from scratch, exploring the various aircraft controls on your own without any guidance!
But even in scientific fields, several studies have shown that direct instruction can be more effective than active methods. In mathematics, Sweller and Cooper found  that an exercise explicitly treated and solved by the teacher was better assimilated than the same exercise that the students had to solve by themselves . Similarly Clahr and Nigham  verified that the quality of memorization and understanding was identical, regardless of the type of pedagogy followed (active or direct).
A theory has been proposed to explain why the active method is not the universal panacea. It is based on the idea of working memory . We know that our working memory has a limited capacity (like your computer’s RAM). If a student has to solve a very open problem, he will saturate his working memory to try to explore the space of solutions, and will have no more available for learning and memorization. Whereas with direct instruction, all working memory is used to understand and learn.