What's the point of classroom displays?

@OhLottie Big Questions board – child led, used as a basis for science investigations, P4C enquiry or just a chat.

@enlimcharas As an MFL teacher, I quickly learned not to display things like numbers – children became too reliant on the walls. Now have grammar rule prompts and key questions to help children think about how to improve quality of work and GCSE mark schemes.
Most of these responses were more or less what I might have expected, but I was really interested in James Theobald’s and Sarah Milne’s suggestion that simply allowing students to outsource their memory to the walls might not be a great idea. This wasn’t something I’d ever considered before. But as soon as I started musing it chimed with the theory of desirable difficulties I’ve been toying with.
For those who’ve missed me holding forth on this, the theory is basically that if we want students to retain information in long-term memory and transfer it between domains we need to induce forgetting. Yes, that sounds completely counter intuitive but one thing I’ve learned is that you can’t always trust your gut.
At the point at which we begin to forget, the theory goes, our brains are at their most receptive and we are most likely to absorb information if it’s presented again. One the many ways to induce forgetting is to introduce variability into students’ experiences. Why? Our memory very quickly becomes reliant on familiar cues. If we learn something in a particular room, our memories associate that room with what we’ve learned, and when we attempt to retrieve that information we use the cues in our physical surroundings to prompt us. So, unless you study in the room in which you will eventually be tested, your memory will be at a distinct disadvantage. But, if you learn in all kinds of different surroundings then the information will be retained without the reliance on familiar cues.
Still with me? OK, so few teachers have control over the rooms they get to teach in, but we do have fairly complete control over what we put on our walls. This adds weight to the idea that seating arrangements and displays should be changed often. As James says, anything which becomes too familiar just becomes wallpaper anyway.
So, what is the point of classroom display? Most people would readily agree that it should support students’ learning. If it fails this uncontroversial test, should we tear it down? And is beauty redundant? If so, how does this square this Ron Berger’s rallying cry that, “If it’s not perfect, it’s not finished”?
It’s certainly true that some of the most useful displays have a charmingly homemade quality, and if we’re going to display students’ work maybe we have to let go our perfectionist ideals. I’ve always enjoyed getting kids to slap post-its all over displays as a record of what they thought or were capable of at a particular point in time. And I loved Alex Quigley’s post on using multiple whiteboards to make learning visible. Great display can often have a temporary feel, and clearly, the more easily it can be changed, the more likely we are to change it.
I’m sure more research would turn up all sorts of alternative perspectives, but hopefully, dear reader, you can identify any gaps in my thinking and fill them with marvellous ideas of your own.