Letter Confusion and Reversals: Why do they occur and how can we help students overcome them?

​I had a big “ah hah!” moment when I recently reread Stanilas Dehaene’s book Reading and the Brain: The New Science of How We Read. In a chapter titled Reading and Symmetry, Dehaene, a French scientist who researches the neural basis of reading (among other things), explains why students often confuse letters such as b / d  or d / p and sometimes read and spell words in reverse. It seems printing letters and words in reverse and reading certain words seemingly backwards typically has nothing to do with visual perception or visual memory. Rather, these things most often have everything to do with something called mirror generalization. 
 
Human brains
Like all animal brains, human brains have evolved in relationship to their environment and physiology. Because we live with gravity, our brains can quickly realize that up is very different from down. Also, because our eyes are fixed in the front of our head, our brains know that ahead is very different than behind. But what about left and right?
 
Consider these three objects, which are presented in Dahaene’s book. Do you recognize them instantly? 

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​Did you initially notice they were spatially backwards? In real life they appear this way:

Mirror generalization
Mirror generalization (sometimes called mirror invariance) arises from our body’s symmetrical nature and can be defined as the brain’s ability to recognize objects regardless of their spatial orientation. Imagine you are walking through a tropical forest and you come upon a bunch of monkeys. Some of the monkeys face you, some face away, some are on your left, others are on your right, and a few hang upside down from tree branches. Regardless of their spatial orientation, you instantly recognize all of them as monkeys. Why? Mirror generalization!
 
Through this generalization, our brains automatically recognize an object regardless of how it is spatially presented. A natural function found in children as well as adults, mirror generalization saves us time and energy and helps us survive. In other words, your brain doesn’t care if a tiger, for example, is leaping at you from the left or the right. You brain’s only concern is to instantly recognize the thing as a tiger and then trigger a response in your body – RUN! The same effect holds true if the object is a city bus and you’re stepping out from the curb – STOP!
 
When it comes to letters and words, however, an object rotated in space is not always the same thing. For example, consider this object - b. In the reading world, this object is the letter b and it represent the /b/ sound. Flip it and it becomes something different. Now it’s the letter d, representing the /d/ sound. Rotate it and it becomes something different again, the letter p. 
 
Mirror generalization is why many young children often confuse d / b and may read was as saw or spell stop as post. Simply put, they have not yet learned to suppress their brain’s tendency to register rotated letter forms and reversed letter sequences as the same object.
 
Here’s a Dahaene quote from a section of Reading and the Brain. Specifically it’s about dyslexia but it references all students. The underlining is mine:
 
“As a matter of fact, letter orientation does pose specific difficulties for large numbers of dyslexic children, who often confuse “b” with “d.”  However, these are problems that are present in all children and not just dyslexics…Furthermore, mirror errors peak at between seven and ten years of age, when children learn to recognize letters, and then vanish.… Visual difficulties do not seem to play a dominant role in most of them.” (page 295).
 
Unlearning is the new learning
To learn that an object in one orientation is a b, another a d, and in a third a p, children must unlearn mirror generalization. But this process of suppression (or unlearning) does not happen naturally. How does it happen? Like the unnatural act of reading itself, most children unlearn their tendency to see a d as a b and was as saw through the efforts of teachers. Through teacher instruction, the brains of students are subtly rewired and mirror generalization, at least when it comes to letters and words, is suppressed or unlearned. In the end, emerging readers and spellers are able to at first intentionally discriminate and later automatically discriminate between mirror letters like p / d and words like stop/ post , was/saw, and net/ten.

How can we helps students?
When it comes to helping students turn off their mirror generalization for letters and words, there are a number of things we can do, especially for students who have brain wiring that is resistant to suppressing or unlearning the tendency. Here are some suggestions, many of which are described and explained in my new Corwin book, How to Prevent Reading Difficulties, PreK-3: Proactive Practices for Teaching Young Children to Read. You can also find video examples of many of them on my YouTube Channel:  https://bit.ly/MWLit_YT_Channel​

• Multi-sensory activities like Sky Writing and palm writing can help some students.

• Consistently use repetition and distributed practice when teaching letter identification/formation and word spellings, as well as direct and explicit instruction. Unsure of what constitutes direct and explicit? Here’s a link to me using one type of direct and explicit instruction to teach a student vocabulary.   bit.ly/Direct_Explict_Vocab

• Directly and explicitly taught spelling activities can help students correct letter confusion within words. So can activities that clearly present correct letter sequences. Below are pictures of two such activities: turning sound boxes (elkonin boxes) into letter boxes or spelling grids.  Another idea is use Dr. Richard Gentry’s “Dot and Check Spelling.” And here’s a  link to a vid that shows me demonstrating Dot and Check.  bit.ly/Dot_Check_Spelling

• Directly and explicitly teach all children to “read through a word,” which means they pay attention to the letter sequence of each word, beginning to end. Don’t let young readers look at the first letters or letters and then make a guess based on meaning. This doesn't mean students shouldn't think about meaning or "cross check" with meaning. Reading is always about meaning! Rather, reading through the words means emerging readers must learn to pay close attention to letter sequence and patterns as they read the word, even as they constantly run this question through their mind: "does that make sense?"

• Conversely, after spelling a word, have students go back and “read through it,” meaning they pay attention to the letter sequence from beginning to end. Provide instant error correction if they use incorrect letters or an incorrect sequence.

• Some students may have weak phonological processing and/or deficits in phonemic awareness. Difficulty with or deficits in sound discrimination can mean subsequent difficulty with orthographically mapping letters and patterns. For these students, teach phonemic awareness to mastery and to the point it reaches an advanced level: sound ID, sound deletion, and sound manipulation. To do this use activities like Penny Pull and Sound ID in Elkonin boxes. Her'e s link to a demonstration:  bit.ly/Penny_Pull

• Be patient. To unlearn or turn off the tendency to mirror generalize letters and letter sequences, some students may need more instruction, at a greater intensity and for longer periods of time than others.

• Last but not least, some students benefit from cursive writing. Recently I've learned of some specialized school programs that teach cursive early, meaning the end of kindergarten or beginning of first grade - for students who may have dyslexia (or have been identified as such). 

 
A Final Thought
Here’s why I used the words typically and most often in my opening paragraph. Earlier I gave this Dahaene quote, “…Visual difficulties do not seem to play a dominant role in most of them.” But Dahaene goes on to say this about some students identified as having dyslexia: “In a few rare cases, however, left-right confusion does seem to be the true cause of dyslexia.” (page 295).
 
It seems one can’t completely rule out left-right confusion and mirror generalization as the root cause of dyslexic behavior in a very low number of students. If you are teacher who works with a student who is not responding to intense, frequent, and long-term reading interventions (such as Orton-Gillingham, LiPPS, or Barton), a team meeting and possibly more assessment are in order. 

Sources/Citations

• Dehaene, S. (2009). Reading in the brain: The new science of how we read. New York: Penguin Books.