How Do We Read? It's Magic (Almost) (1)
Hey smart people, Joe here.
Today I'm going to teach you how to read. Which is something that you already know how to do,
obviously, but you probably have no idea how you're actually doing it.
But first I need to let you in on a secret:
There's a trick being played on you every time you read something.
In fact it's right in front of you right now. Do you see it?
Let's take a closer look at just a couple of letters and see if you can see it then.
Here's just the C and T. These two letters are exactly the same weight,
or “size” in this typeface, so you'd figure they're the exact same height.
But watch what happens when I lay them on top of each other. The C is ever-so-slightly taller.
It's true for other letter pairs too. Like E and S. The S is taller.
It's even true for other typefaces, like this one.
Letters that look the same size are actually… not the same size.
And this… is on purpose.
Because if they actually were the same size, mathematically speaking
they wouldn't look the same size.
Letters with rounded tops have to be slightly taller than letters with flat tops in order for
them to appear the same size. This illusion is hiding
in just about everything you've ever read. Yes, it's even in Comic Sans!
Your letters are lying to you! But if this illusion
wasn't there, words would look really weird.
And that's because we don't read with a ruler.
We read with our brain. And our brains like to lie to us.
The reason all this happens is related to another illusion that maybe you've seen before.
This line appears longer than this one. But in reality the two lines are the same length.
This is one of the most famous illusions in visual science.
And there's lots of different versions of it. I mean, this is one of the most
powerful illusions I've ever seen. Even when you know the lines are the same length,
it doesn't change the story your brain tells you. It's really weird!
So what does this have to do with letters?
Well, we can explain what's happening here
if we turn the Müller-Lyer illusion on its side:
This line, with its ends, looks kinda like the letter O.
The other line is more like an I or a T.
Our brains decide round letters like O look smaller than more squared off letters nearby,
so we have to make the O bigger just to look the same size.
So that's a really cool illusion that fools you probably
hundreds of times a day. And it shows us that there's a lot more going on with how
we recognize letters and words and turn them into meaning than you might expect.
In other words: Reading is really weird.
Now, a good reader can recognize hundreds of words per minute.
And once you learn how to do it, most of us don't have to actually think about reading.
It just happens.
But while it feels automatic, there's a lot going on under the hood.
Or under the skull really.
You're just not consciously aware of any of it.
When ya think about it it's actually pretty weird that we can read at all.
I mean, our brains evolved, pretty much in their current form, a hundred thousand years ago or so.
But writing is only a few thousand years old.
And standardized movable type, that was only invented like one thousand years ago, in Asia.
And then Gutenberg invented it again like 600 years ago.
I mean think about this: As recently as the 1800s maybe 1 in 8 people actually knew how to read.
It's clearly not something that we evolved to do. But we can. So what's up with that?
Luckily I happen to know a language expert, and she just so happens to have her own YouTube show.
So I asked her. Thanks, Joe! I'm
Dr. Erica Brozovsky, sociolinguist and certified word nerd. On my show Otherwords,
we delve into the amazing facets of human language,
and the ability to read is one that almost defies logic.
How can a brain that evolved like a hundred thousand of years ago be so naturally good
at a skill that we only invented 5,000 years ago? It's been called the “paradox of reading”
The answer may be that we've repurposed some existing brain functions for new uses.
It's a theory neuroscientist Stanislas Dehaene called "neural recycling"
By studying the neural patterns of monkeys, scientists have been able to identify how
their brains identify and make sense of the contours and lines that make up visual scenes.
A corner here, an edge there, some intersecting edges here. And it seems like there's a basic
"alphabet" of simple shapes that their brains use to decode any number of possible scenes.
What's interesting is these shapes are remarkably similar to the strokes that
make up most human writing. Whenever one object is behind another, you get a T
shape. Corners of objects make L's and F's and Y's.
And an O can be found in anything from a delicious fruit… to the eye of a predator.
What these shapes have in common is that they're "non-accidental". If you threw a bunch
of toothpicks on the floor, very rarely would three land with their ends perfectly touching.
So if you see this pattern in real life… it's probably worth paying attention to,
and our brains are especially adept at spotting it.
Each pattern in this “shape alphabet” triggers neurons,
and when certain combinations of neurons fire together,
they trigger higher order neurons that help us eventually decode the meaning of an image.
So this combination from our shape alphabet triggers the meaning
“cat”. And so does this combination. Only, one is a group of shapes in nature,
and one is just a collection of lines on paper.
Early alphabets that used such shapes allowed more people to read, and let them read faster,
eventually replacing cumbersome pictographic writing systems like Egyptian hieroglyphics.
As Dehaene says, "...our cortex did not specifically evolve for writing…
writing evolved to fit the cortex."
That… is amazing.
So let's take a closer look at what's happening
when your brain decodes all these shapes and tries to make meaning out of them.
How do we read?!
One thing that we know about reading
is that your brain isn't sounding out words as you scan the page, like
speaking them in your head. I mean, you might be able to make yourself consciously do that…
One fish, two fish, red fish, blue fish
That's not how it works.
When you read, your brain is directly turning those printed symbols into meaning.
Now, words are made of letters.
And we've already seen that we're really
sensitive to the shapes combinations of letters have when they're put together.
So the big question to figure out is: When we recognize a word, do we see a whole word and just
recognize it by its shape? Or do we actually read the letters?
You can think of the question this way: When I see an elephant, do I see all the individual parts:
it's big, it's gray, ears, trunk, tusks, and recognize it that way?
Or do I just see the whole thing and say “that's an elephant”?
To figure that big question out, in the 1880s a psychologist
flashed words or letters in front of people for just a few milliseconds.
And people more accurately recognized the whole words than letters all alone.
And later experiments in the 1960s flashed either real words or nonsense words in front of people
then asked if they recognized some particular letter
And people recognized the right letter better when it was in a real word.
These were a pretty good hint that, to our brains, there's something special about
whole words over just letters. The “Word Superiority Effect.”
And this is kind of strange when you think about how we learn to read. When we're young
we make words by sounding out the letters or combinations of letters in the order they appear.
av-o-cah-do
That's the “phonics” in “hooked on phonics”
But the word superiority effect says that once we learn to read,
we don't actually process words like that. We just… see the word. And we recognize it.
Now, at first scientists thought we recognized the literal shape of the word.
Like if your brain sees this shape it analyzes that pattern of ascending and
descending characters, and the word “shape” must be inside.
And this makes sense! We tend to read lowercase faster than all caps,
where the letter shapes aren't as prominent.
And (unless you're super emo) we are terrible at reading AlTeRnAtInG upper and lower case.
But that word shape explanation turned out to be a little too simple. Because
you can't spell READING… without the eye.
Because . . . eye . . . reading . . . never mind.
Now, obviously your eyes move when you scan a page. But they're not scanning
smoothly across lines of text. They jump around. Sometimes they even jump backwards.
These little movements are called saccades. And they're
really fast. One jump takes 20 to 35 milliseconds. Around 10 times faster than the blink of an eye.
You don't even notice this jumping because it happens so fast it doesn't even have time
to register in your brain. But why can't we see those jumps? Does anyone know a neuroscientist?!
So here's the crazy thing about saccades: Your eyes are jumping around about
three times a second, and in between that they're making these little micro
saccades, they're making little tiny jitters.
But you can't see the whole world streaking by.
Why not? Well it's because when your eyes go on this ballistic jump if we
were actually seeing that it would look like the world is streaking around all the time
So we don't experience that. Instead we just experience the world out there. Why?
It's a very deep reason actually. It's because all you're ever seeing
is your internal model of the outside world. You're not seeing the world as it is.
Because it actually takes time for your eye to move from one place to another.
So what happened to that time? Well it turns out
your brain says okay i'm going to fill in the gap with whatever I land on.
When your eyes land on the thing you've got this gap in time
and so your brain essentially retrospectively fills that in.
Thanks David Eagleman! Your eyes stop on a word for about 200 milliseconds,
then they jump forward 7 to 9 letters. But somehow your eyes never land in between words.
And some types of words: like short words or connector words like “the” and “and”
Your eyes just skip right over them altogether.
Now, how much information we gather each time our eyes stop is limited by how our eye is built.
The fovea is the area in the center of your vision where the photoreceptors are most densely packed,
and where your vision is the sharpest. It senses an area about the size of your fingertip
at arm's length. Around that is an area called the parafovea.
The photoreceptors are less dense, and it can see some details but things are kinda fuzzy.
And beyond that is basically your peripheral vision, where the photoreceptors can basically
just tell that there's something there, but are absolutely terrible at figuring out what.
Each time your eyes stop, in that split second you're
gathering information from three different zones.
In the center, your fovea clearly identifies 3 to 4 letters around
where your eyes stop. This is usually enough to recognize that single word.
The second zone is in the parafovea. It's much more blurry,
but can get at least a hint at what the first few letters of the next word are.
