Learning is invisible, as David Didau loves to point out. We can only observe current performance, and if we take current performance as a guide to long term learning, we are deluding ourselves.
The fact that learning is invisible renders graded lesson observations invalid. It is the height of hubris to claim to be able to observe progress, or lack of it, in the space of one lesson. The pernicious practice of grading lessons has been abandoned by Ofsted, but it is still poisoning the lives of many teachers across the country, as this blog post illustrates painfully and vividly.
The obsession with the lesson as a unit of time in which certain fixed things must take place has had another damaging result: the introduction of ever longer lessons. A colleague in an independent school where I previously worked once lamented the thirty-five minute slots used there, and reminisced about the eighty minute lessons of her former state school employer. She claimed that the pupils really went on a ‘learning journey’ in those longer lessons.
This ‘learning journey’ is precisely the kind of illusion which gives the appearance of progress, while slowing down the process of genuine mastery. In eighty minutes all sorts of performances can be extracted from pupils, and after having ‘journeyed’ through so many of them, they will doubtless be ready to perform some beautiful hoop-jumping that will impress an inspector who is suffering from the hubris mentioned above.
But does all this wonderful performance mean that they have actually remembered anything? In fact, this long period of time spent on one topic doing all sorts of activities is precisely the worst way of acquiring mastery.
Long term remembering is greatly aided by spacing and interleaving. Spacing is doing small amounts of practice separated by intervals of time. When you do this, the fact that you start to forget the material and have to make the effort to recover it helps to forge long-term memories. Interleaving works in a similar way, but instead of just space between practice, you do something different between each session. Doing something different is even more effective at causing that partial forgetting which is so useful in the long term for remembering (see Wrong Book, p192 and p228 for more detail on these principles).
In a traditional school timetable, with lots of brisk, short lessons in different subjects, spacing and interleaving is just part of normal business. Pupils continually have to make the effort to remember what they did last time, thus helping them to forge long term memories.
Of course, it’s hard work, and longer lessons could have a much greater feel-good factor, especially if the teacher has slaved away to make those eighty minutes a veritable theme park of thrilling educational rides. After all, one couldn’t actually expect them to work for eighty minutes, right?
UPDATE: Heather Fearn has written about this as well, here.