How decoding dyslexia can help decode the mind

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 k 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.