How Decoding Dyslexia Can Help Decode the Mind

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During this school year, thou­sands of chil­dren will begin read­ing. Despite their best efforts, how­ev­er, up to a tenth of them will strug­gle. If we were aware of the early warn­ing signs, we could help these chil­dren by using research-based remediation. But dyslex­ia is poorly under­stood by the public. Unveiling these mis­con­cep­tions can help mil­lions of chil­dren. It could also help decode the human mind.

To shed light on the public view of dyslex­ia, let us take a moment to play clin­i­cian. Consider John and Jack, who suffer from read­ing dif­fi­cul­ties. John con­fus­es let­ters, like b and d, while Jack strug­gles to link let­ters with sounds; he doesn’t rec­og­nize that kat sounds like the name of a famil­iar animal. Which one has a read­ing dis­or­der?

If you are like most laypeo­ple, you would prob­a­bly think John’s letter rever­sals are the tell­tale sign of dyslex­ia. But read­ing sci­ence sug­gests oth­er­wise. Dyslexia, to be clear, is het­ero­ge­neous, and its many symp­toms include visual difficulties. But letter rever­sals are common in all preliterate children, not in dyslex­ia specif­i­cal­ly

Jack’s dif­fi­cul­ties, how­ev­er, are quite typ­i­cal of dyslex­ia. Skilled readers rou­tine­ly link let­ters to speech sounds, or phonemes (e.g., c→k), so they read­i­ly rec­og­nize kat and cat as homo­phones; they sound alike. This process (phono­log­i­cal decod­ing) is uncon­scious and auto­mat­ic, yet it’s an inte­gral part of read­ing. But in dyslex­ia, this process is disrupted.

The roots of the prob­lem arise much ear­li­er. Before a child learns to read, she needs to recognize that spoken words are com­posed of sounds (e.g., cat begins with a sound), or else, the func­tion of let­ters is mys­te­ri­ous. But for chil­dren with dyslex­ia, phone­mic aware­ness is difficult. Speech perception is like­wise atyp­i­cal. Infants who are at risk for dyslex­ia (because dyslex­ia runs in their fam­i­lies) show atyp­i­cal brain response to speech well before they ever read their first word. And since the read­ing brain net­work “recycles” the speech and lan­guage net­work, an atyp­i­cal speech system begets atyp­i­cal read­ing.

So read­ing and dyslex­ia illus­trate the rich ten­sion between nature and nur­ture. Reading is a learned skill; no one is born read­ing. But learn­ing to read relies on inborn human capac­i­ties for lan­guage and speech. And dyslex­ia is a genetic con­di­tion that com­pro­mis­es these brain networks.

Yet laypeo­ple are con­vinced that dyslex­ia results from “troubles with vision. And these errors matter. A parent who holds these views might fail to rec­og­nize her child’s dif­fi­cul­ties with rhymes and pig Latin (both require phone­mic aware­ness) as warn­ing signs. So why are we so wrong about dyslex­ia? Why do we mis­take dyslex­ia for “word blind­ness”?

At first blush, these mis­con­cep­tions seem rather inno­cent; laypeo­ple, by def­i­n­i­tion, aren’t read­ing experts, so per­haps they just don’t know better. But aspir­ing teachers, with ample edu­ca­tion­al train­ing, make sim­i­lar mis­takes. Moreover, the pat­tern of mis­takes sug­gests a deeper prob­lem.

Remember our “play clin­i­cian” exer­cise? When my lab pre­sent­ed these ques­tions to laypeo­ple, par­tic­i­pants not only failed to rec­og­nize phono­log­i­cal decod­ing dif­fi­cul­ties as a symp­tom of dyslex­ia; they also failed to view them as bio­log­i­cal.

This error is telling. If people believe that cog­ni­tion, such as phono­log­i­cal decod­ing, is ephemer­al and dis­em­bod­ied (it’s just “in your head,” not in your brain/body), but they cor­rect­ly believe that dyslex­ia is bio­log­i­cal­ly her­i­ta­ble, then it’s no wonder they con­clude that phono­log­i­cal symp­toms cannot pos­si­bly arise from an inborn source. Vision, on the other hand, seems patent­ly anchored in our body (eyes), so a priori, “vision trou­bles” sug­gest a bio­log­i­cal genet­ic eti­ol­o­gy. Consequently, laypeo­ple strug­gle to link dyslex­ia to its true cog­ni­tive ori­gins, and instead, pre­sume a sen­so­ry visual cause.

So if we grant people the irra­tional belief that phono­log­i­cal decod­ing is “ephemer­al,” then we can now under­stand why they strug­gle to link dyslex­ia to phono­log­i­cal decod­ing. But why would this irra­tional premise arise in the first place? Why do people believe that the cog­ni­tive process of phono­log­i­cal decod­ing is ephemer­al?

In a new book, I show that this pre­sump­tion applies to cog­ni­tion quite gen­er­al­ly. People read­i­ly assume that our sensations and emotions are inborn. But they deny the innate­ness of abstract cog­ni­tive con­cepts such as number (e.g., “two objects”). And they are wrong; new­borns demonstrably pos­sess such notions. Critically, the denial of innate cog­ni­tion is linked to its per­ceived “disembodiment”; the more “ephemer­al” a capac­i­ty seems, the less likely it is to be con­sid­ered inborn.

I thus believe that these errors — whether they con­cern typ­i­cal cog­ni­tive capac­i­ties of new­borns or the atyp­i­cal cog­ni­tion in dyslex­ia — arise from a single cause: from people’s tacit beliefs about how the mind works. Paradoxically, these beliefs are guided by the very prin­ci­ples that make our mind tick.

One prin­ci­ple, known as essentialism, sug­gests to us that the inborn essence of living things resides in their bodies. Children, for instance, believe that a dog is brown because it inher­it­ed some tiny piece of matter from its bio­log­i­cal par­ents. Another prin­ci­ple—dualism—sug­gests to us that the mind is ephemer­al, dis­tinct from the mate­r­i­al body. So if (per essen­tial­ism), inborn capac­i­ties must be embod­ied, where­as if (per dual­ism) the mind is dis­tinct from the body, then it follows that dis­em­bod­ied capac­i­ties cannot be innate. And since cog­ni­tion appears ephemer­al, we con­clude it cannot be innate, and this applies to both number and phono­log­i­cal decod­ing.

While these biases are uncon­scious, they demon­stra­bly veer off rea­son­ing in numer­ous areas, from our irra­tional fas­ci­na­tion with the brain to our fear of artificial intelligence; our trou­bles with dyslex­ia, then, are but one of its many vic­tims. To counter these errors, infor­ma­tion alone won’t suf­fice — a real change requires that we take a hard look within.

Reading, then, rests on decod­ing in more ways than one. For chil­dren to suc­cess­ful­ly decode print­ed words, we must all improve our decod­ing of the human mind.

Scientific American source|articles

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