Why Reversals Are Normal … Until They Aren’t

I have a demonstration that I use for parents and professionals to show why letter reversals are a normal part of development.  It’s something that I visualized awhile back and that Toni Bristol helped me to put down on paper.  We refer to it in conversation as “The Chair Demo”.

Let’s consider an object such as a chair.  As you can see on the top row, there are many types of chairs and that each one looks quite different.  So what constitutes a “chair-like” quality?  Or more specifically, what are the components of an object that make it a chair?  Well you might be tempted to identify a chair by it’s legs, because that’s what enables it to stand upright, and a chair is four-legged – right?  Not necessarily!  If you look at the chair on the right end of the top line, you’ll see that it has only one molded leg that might have given Escher his original idea.  In fact there’s a bean bag category of chair that has no legs at all!  The reason even very young kids can group all those objects as chairs is that they share the common properties of a bottom for your bottom and a back for your back.

Now let’s go to row two of the demo.  Now you have four objects that look much more alike than the objects in row one.  In fact, they look so alike that we give them a specific name,  just like the bean bag chair is its own category.  We call it a folding chair because it has legs that can be tucked under it to lay flat.  The orientation of the folding chairs in row two don’t matter.  They can be facing up, down, left, or right – or even folded and stacked when their visual image is quite different -but they each have the same name:  folding chair!  Young children learn this as part of the rules of object constancy.  So when you ask little Johnny to bring you a folding chair, you’re impressed that he doesn’t come back with any of the chairs on the top row of the demo.

Ah … but now to the objects on row three.  Little Johnny goes to pre-K, and the teacher shows him this thing – and calls it the letter “b”.

Then the she shows him this letter:

At first little Johnny thinks it’s a “b”.  After all, I get congratulated when I know that this thing:

… has the same name as this thing:

But now the rules have changed, and we tell little Johnny – no, no, no!  The laws of object constancy don’t apply when it comes to lower case letters.  The single name category isn’t good enough, and the letter has a totally different name, symbolism, and purpose depending on whether the stick is on the right side of the ball or the left side of the ball.  Little Johnny is going to ponder the question along with little William: “The ‘b’ or not the ‘b’ … that is the conundrum”. And not only that, there are four stick and ball letters with the same orientations as the folding chairs, and when we get deeper into the alphabet they’re going to have to learn how to differentiate “p” from “q”!

The chair paradox came to mind when listening to an NPR piece the weekend before last titled “B and D Learning Process Debunks Dyslexia Jumbled-Letters Myth“.  From the transcript:

EMANUEL: And when you do learn how to read, this part of the visual cortex helps you recognize letters and words. But since the area’s original purpose was to recognize objects, it’s wired to recognize one object from many different angles.

GUINEVERE EDEN: When I see a chair from one angle and I see it from the other angle, I still know it’s a chair. I just know that it’s been rotated. But in reading, you have to overrule that system so that you know that B and D are two separate objects.

Actually Stanislas Dehaene was the first to tease this out, and you can get a taste of his thinking in this Scientific American piece or in his Trends in Cognitive Sciences article.