b and d Reversals: Normal or Not?

Reversing b and d is ordinary in kindergarten and first grade, and it is poor evidence of dyslexia on its own. The best study on this point followed 130 children and found that although overall letter writing accuracy predicted later reading skill, the specific tendency to reverse letters did not. Reversals matter when they sit alongside reading and spelling difficulty, not when they turn up in a five year old’s name practice.

What the research actually shows

Rebecca Treiman and colleagues had children write letters to dictation at a mean age of five years and eight months, then measured literacy at a mean age of eight years and four months. Their 2014 paper in Scientific Studies of Reading reports that children who later scored poorly on literacy measures reversed letters at almost exactly the same rate as children who did not (roughly .59 of left facing letters versus .55). The authors state the implication directly: “Educators and clinicians, therefore, should not assume that reversal errors in writing are indicative of dyslexia.”

That is worth holding onto, because the reversal myth is durable. It survives partly because reversals are visible. A parent can see a backwards d on the fridge, whereas weak phonemic awareness is invisible without testing. The visible thing gets blamed.

Why d gets reversed more often than b

Reversals are not random. Treiman’s group found children reverse letters that face left, such as d and j, far more often than letters that face right, such as b and c. The reason is statistical: most Latin letters carry their appendage on the right, so children implicitly absorb a rule that letters face right, and they fall back on it whenever they cannot recall a particular letter’s orientation.

Jean-Paul Fischer found the same pattern in French children and named it the implicit right writing rule. In a study of 300 five and six year olds published in Cortex, the effect was strong enough that the preceding character changed the outcome: 73 percent of children who correctly wrote the letter C then mirror wrote a following digit 3, while only 10 percent of children who mirror wrote C also reversed the 3.

Two practical consequences follow. First, “b and d confusion” is slightly misleading. The dominant error is writing b when d was intended, because b is the default. Second, a child who reverses letters is not confused about b and d as a pair. They are guessing at orientation for a single letter, and the guess has a direction.

The deeper cause is a feature of vision, not a defect. The brain treats a mirrored object as the same object, which is useful for recognizing a chair from either side and unhelpful the moment letters arrive. Felipe Pegado’s 2022 review in Frontiers in Human Neuroscience describes this mirror invariance as a pervasive difficulty at the start of literacy that “can persist even after 2 to 3 years of literacy practice.” Brain imaging fits: Blackburne and colleagues found in PLoS One that adults show widespread visual and parietal responses to letter orientation while children show far less, and concluded that the specialized processing for distinguishing letter orientations develops slowly and stays immature even in older children.

Normal, or worth a second look

Pattern	How to read it
Occasional reversed b, d, p, q, or digits in kindergarten and first grade	Expected. Correct in passing, do not drill it
Whole words written right to left in preschool or kindergarten	Common at this age and usually self resolving
Reversals concentrated on left facing letters (d, j, p)	The typical developmental pattern, described above
A left handed child reversing letters	No more likely than a right handed child. See below
Reversals still frequent through second grade and slow, effortful reading or spelling	Worth a literacy screen
Reversals when copying a letter that is right there on the page	Worth attention, this is a different problem from recall
Reversals plus poor letter formation, illegible spacing, and avoidance of writing	Worth an occupational therapy conversation

The pairing in those last rows is the point. Reversals alone are weak signal. Reversals plus a reading or spelling difficulty, or plus broad handwriting breakdown, are worth acting on, and the reading or handwriting difficulty is the reason to act, not the reversals. If that is where you are, when to ask for an OT handwriting evaluation and dysgraphia or just messy handwriting cover the next steps.

One myth to retire while we are here. Mirror writing has long been blamed on left handedness. Fischer and Koch compared 59 left handed and 59 right handed writers matched for age and school experience and found clear evidence against the handedness explanation and in favor of the right writing rule for both groups. An earlier pilot study by Cubelli and Della Sala reached the same conclusion, describing mirror writing as age related but independent of handedness.

Why the bed trick is weaker than it looks

The bed mnemonic asks a child to picture the word “bed” as a bed frame, with b as the headboard and d as the footboard. It is not useless, but look at what it requires at the moment of writing: stop, recall an image, orient the image correctly (which is the exact skill in question), map the left post to b, then map back to the letter being written. That is four steps of visual recall in the middle of composing a sentence, and the second step asks the child to do the thing they cannot yet do reliably.

Teaching the formation difference asks for one step, and it happens before the ambiguity arises:

• b starts with a straight line down from the top line, then the pencil retraces up and pushes the bump out forward.
• d starts with a curve. Round back and around first, the same opening stroke as c and a and g, then a tall line down through it.

The child never has to decide which way the bump faces, because the bump is a consequence of where the pencil started. That converts a visual memory problem into a motor sequence, and motor sequences are what handwriting practice actually builds. It also matches the mechanism in Fischer’s account: reversals appear when orientation memory fails and the default takes over, so the fix is to give the letter a second retrieval route that does not depend on orientation memory at all.

What to do about it

Teach the two letters far apart. b and d are a classic example of why alphabetical order is a poor teaching sequence. Introduce b with the downstroke family (l, i, t, h, r, n, m) and d with the curve family (c, a, o, g, q). Putting weeks between them means the child builds two separate motor habits instead of one confusable pair. More on this in why the alphabet is the wrong teaching order.

Name the starting stroke out loud, every time. “d starts like c.” Say it while the child writes, not after they finish. The correction has to land before the pencil moves, otherwise you are only marking errors.

Practice in words, not in rows. Twenty copies of d teaches nothing about choosing between b and d, because there is no choice to make. Short words that mix both letters force a decision on every letter: bed, dab, bad, bid, bud, dib. The worksheet generator will set any word list you type on three line paper with dotted tracing, so you can build exactly that mix rather than the single letter pages most printables offer.

Keep the letter pages for formation, not repetition. Our letter b page and letter d page show the stroke order and starting point for each, which is the part worth reviewing before a practice session. The full set is at /letters/.

Correct lightly and move on. Circling every reversal on a page of writing tells a six year old their writing is wrong without telling them what to do. Pick one word, model the starting stroke, have them write it twice, and leave the rest.

Do not use mirrored or reversed practice material. Worksheets that ask a child to identify the wrong version give practice looking at the incorrect form. The evidence base for or against this is thin, but there is no reason to spend limited practice time producing the error you are trying to eliminate.

If reversals are still routine well into second grade, the useful next move is not more handwriting drill. It is a reading and spelling screen, because that is where the actionable information is. Handwriting practice will keep improving formation either way, and the broader sequence is in how to teach handwriting, step by step.