Sunday, March 29, 2020

Mirror-writing intersects with fundamental questions about the neural representations for reading and writing, and for object recognition and purposeful action more generally

Reflecting on mirror-writing. Interviewing Robert McIntosh and Sergio della Sala. The Psychologist, April 2020 Vol.33 (pp.32-35), Mar 2020. https://thepsychologist.bps.org.uk/volume-33/april-2020/reflecting-mirror-writing

So, would it be normal for children to mirror-write?
Mirror-writing, though striking to see, is an absolutely normal occurrence when learning to write. It would surprise us if there are any children who never make at least some mirror reversals. Rather than being regarded as a mistake, mirror-writing can be viewed as an impressive act of generalisation from a child, who is able to produce mirrored forms that they have never been taught. Parents with a young child who mirror reverses letters or words should enjoy the variety, and should not worry. Such reversals would only be of concern if they persisted well beyond the age by which most children have securely learned letter direction (7-8 years), in which case they would be part of a broader profile of slow literacy development.

Is there any update on mirror-writing from your own research or other sources?
Mirror-writing is still a ’niche’ research topic, but a few recent papers have been published on developmental mirror-writing. Jean Paul-Fischer’s group in Lorraine (France) had previously shown that children learning a dextrad (left-to-right) language like French (or English) are much more likely to reverse characters that face to the left (like j, z, or 3) than those that face to the right (like k, s, or 6). They inferred that the child may implicitly learn that most letters they see face to the right, and then over-apply this rule, so that they are more likely to flip a left-facing character to the right than vice-versa. We recently confirmed that this bias really is driven by character orientation, and not by differences in frequency, or how hard it is to remember certain shapes. We taught primary school children to write four novel pseudo-letters, two of which were left-facing and two of which were right-facing. We used identical but mirror reflected character sets for different groups of children, to control for any incidental differences between the shapes. Children were three times more likely to mirror-write a novel character they had learned in a left-facing format than to mirror-write one they had learned in a right-facing format.

Interestingly, it turns out that the bias may not be so much about whether the character faces left or right, but whether it faces in the direction of writing. Fischer and his colleagues used a simple technique to bias children to start writing in a right-to-left (i.e. reversed) direction, and they found that the pattern of reversals was also reversed, so that right-facing letters were now more likely to be flipped than left-facing characters. So, it seems that children may generally learn to face characters in the direction of writing before they know which way each of the individual letters should face.

And there is one point in our previous article that we would now revise. We suggested that mirror-writing in children was driven mainly by uncertainty about the direction of writing actions, and not by perceptual uncertainty about how the letters should look on the page. We have now tested this idea more directly, and found that there is in fact a close relationship between a child’s likelihood of mirror-writing and the errors they make when perceptually judging whether normal and reversed characters look correct or not. This relationship was significant even when controlling for age; and the letters that were most often mirror-written were also more prone to recognition errors. These new data indicate that perceptual uncertainty does accompany mirror-writing in children, and that visual and motor representations of letters develop in parallel.

What questions on mirror-writing are still unanswered?
One major shortcoming is that most of what we know about mirror-writing relates to dextrad (left-to-right) languages based on the Latin alphabet, which is only one class of directional writing system, so cross-cultural studies seem essential. How do these phenomena compare in other language systems, especially sinistrad (right-to-left) written languages such as Arabic or Hebrew? Bilingual children, being schooled both in dextrad and sinistrad languages, might be particularly interesting to study. We have unpublished data suggesting that children learning to read and write both English and Arabic make more orientation errors for left-facing characters in English and for right-facing characters in Arabic, consistent with a general bias to prefer letters that face in the script direction. It might also be interesting to examine the relation of reading and writing to other culturally-specified directional behaviours (such as turning taps or screws).

In adults, we would be interested to investigate a possible association of mirror-writing ability with atypical language dominance. We have functional magnetic resonance imaging data showing an unusual pattern of bilateral language representation in a skilled mirror writer. This result is intriguing, but it is not yet known whether it is typical of people who have a facility for mirror-writing. The extensive email correspondence that our Psychologist article has elicited has convinced us that there would be plenty of candidates for a larger-scale study. However, in pursuing this question it would be essential to define more precisely what should qualify a person as being a ‘natural’ mirror-writer; because mirror-writing is also a skill, like any other, that can be developed and made automatic through practice.

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