Dyslexia Doesn’t Work the Way We Thought It Did

Dyslexia Doesn’t Work the Way We Thought It Did

Anna Nowogrodzki

Studies find it’s the quick loss of recent implicit memory that is holding the brain back.

Dyslexia is not just about reading, or even language. It’s about something more fundamental: How much can the brain adapt to what it has just observed? People with dyslexia typically have less brain plasticity than those without dyslexia, two studies have found.

Though the studies measured people’s brain activity in two different ways and while performing different tasks, researchers at the Hebrew University of Israel, reporting in eLife, and researchers from MIT, reporting in Neuron, both found that dyslexics’ brains did not adapt as much to repeated stimuli, including spoken words, musical notes, and faces.

Both sets of researchers found that people with dyslexia more quickly forget recent events. This type of memory is called incidental or implicit memory, and includes anything you didn't know you needed to remember when it happened. Because of how quickly their implicit memory fades, dyslexics' brains don't adapt as much after reading or hearing something repeatedly—which is perhaps why it is harder for their brains to process the words they read.

Dyslexia Doesn’t Work the Way We Thought It Did

Anna Nowogrodzki

It’s more nuanced than that I think... network spacing is wider for dyslexics, so it’s harder to make the longer connections necessary for learning, thus small bits of unconnected information with little significance are too small to make the long connections necessary. Thus small bits of information are too small to connect up easily without lots of repetition... but finding and absorbing large concepts based on existing learning are far easier for dyslexics to connect up... indeed the increased spacing seems to have plenty of very useful abilities not available to the general population with average network spacing.

You can think of being in a wood, at night in the dark with a torch. The trees density of planting representing network spacing... a person with Aspergers may have very dense networks, analogous to very densely planted trees. If you turn the torch on, it’s light will not reach very far into the wood, because of the density of the trees. But it allows them to process tiny bits of data very easily. The dyslexic on the other hand is at the other extreme, and has really widely spaced networks, analogous to widely spaced trees planted far apart. In a dyslexic’s case, when you turn the torch on, it’s beam goes a long way into the wood, this allows them to process very widely spaced data, but struggling badly with the tiny stuff. It just falls through the gaps between the trees. The great bulk of people fit in the middle of the standard bell shaped curve, with average spacing.

But there are other aspects to network creation beyond spacing... there us also speed of network creation (also partly affected by spacing), and very importantly speed of network erosion. Neither of these are well understood, but they also clearly contribute to how different people learn, and how differently they adapt.

Fascinating subject area... the type of academic learning we favour today, may simply favour those with particular spacing, creation and erosion speed...

My own sneaking suspicion is that Dyslexia / autism/Aspergers is a natural adaptation to our types of society...