Imagine that your mind is a bunch of Christmas trees. Note that I wrote, ‘imagine’. I am not claiming your mind is literally a bunch of Christmas trees, which may seem obvious but is nonetheless important, as we shall see later.
Anyway, go with it for now.
Every time you learn something new, you hang it on one of those Christmas trees. Most of the time this is not a problem. One of the trees might be something like, ‘People desire power’, and the thing you hang on it is a specific instance from history of someone seeking power. You are adding specific details to a broad idea you already hold.
This is how most learning proceeds and that is that.
However, some ideas end up on the wrong tree. You may have the right tree available but still hang it on the wrong one, or you may not even possess the right tree.
Possibly the most well-researched examples of this kind involve physics (although the idea extends to any conceptual change). For instance, our intuitive views of motion tend to be wrong. We have a tree that represents, ‘Things move because they feel a force,’ and then we hang observations onto this; observations like the motion of a football. Physics teachers instead want their students to think of moving footballs in terms of Newton’s first and second laws of motion.
Empirical data suggests that we can go to quite heroic efforts to hang things on the wrong tree. We will rationalise new observations. Even attempts to induce ‘cognitive conflict’ by demonstrating that a particular observation is inconsistent with a particular tree tend to be twisted into compatibility. If I point out that nothing is pushing a football through the air, you might decide there is some residual force still left over from the kicking foot.
And yet we do, rarely, manage to change our understandings of concepts and so there must be some mechanism by which this is possible.
Stellan Ohlsson has developed a theory to explain what is going on and I’ve already been using it in this post. In his view, we collect specific bits of knowledge, observations, beliefs and so on under different theories – my Christmas trees. The theories do not have to agree with each other and the specific bits of knowledge are not logical consequences of the theory. Instead, when we encounter something new, we look for the best theory to hang it under. These need to be locally coherent, but nothing more. We simply lack a system for going through each item and checking its logical consistency.
Ohlsson suggests that each of these bits of knowledge are subsumed under different theories. If you want to move them then you need to resubsume them under a different theory.
This is hard but not impossible. Once you have both theories available in your mind, you can start to try to hang each piece of knowledge under each theory. A process of competition begins between the two theories until with most useful one wins through. This is how conceptual change occurs: Resubsumption Theory.
Ohlsson is coy about suggesting implications for teaching, noting that other factors could be far more important in conceptual change than any implications of Resubsumption. However, he does note a few things that should give us pause for thought.
The idea of developing new ideas in supposedly ‘relevant’ contexts may be misconceived because it may lead to students hanging the new knowledge under the theories they already associate with those contexts. Instead, it may be better to first make the new theory available to the students in an abstract form such as a computer generated microworld. Instead of familiar footballs and rockets, we could develop Newton’s laws in a virtual world. Once the new theory is available in the minds of students, the process of competition and resubsumption can begin.
This is an interesting idea.
Like Cognitive Load Theory, Resubsumption derives from information processing theories that model the mind as a computer. This has led to some criticism on the basis that minds are not computers.
I do not believe that minds are computers any more than I believe that they are made of Christmas trees. But I think it’s a pretty good theory to subsume some of our findings under, for now.