Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal

Corballis, Michael C.

doi:10.3389/fnhum.2018.00140

Cited by 28 publications

(33 citation statements)

References 92 publications

(101 reference statements)

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“…Consequently, the representation of the character in the child's memory has no orientation. We do not exclude that the absence of orientation can in fact result from two differently oriented representations, perhaps one in each hemisphere [60], whose accesses are random or determined by situational or cultural constraints. However, the analysis for the digits [38], on the basis of a character feature set [71], suggests rather a single representation.…”

Section: Discussionmentioning

confidence: 95%

“…Many authors make play a differentiated role to the two cerebral hemispheres in their theory of mirror writing [58][59][60]. Whereas Orton's theory [58] was shown to be difficult to reconcile with the data by Fischer and coworkers (see Section 3), Corballis' theory [60] was estimated to be compatible with these data [61].…”

Section: Is There a Differentiated Role For The Cerebral Hemispheres?mentioning

confidence: 97%

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A Synoptic and Theoretical Account of Character (Digits and Capital Letters) Reversal in Writings by Typically Developing Children

Fischer

Luxembourger

2018

Education Sciences

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Reversing characters (digits and letters) when writing, and complete mirror writing, raise one of the oldest and most mysterious questions in developmental and educational psychology: Why do five-year-old children write symbols (e.g., ∃ for E) they have neither learnt nor seen? Attempts to draw up a complete explanatory theory of character reversal in writings by typically developing children were long hindered by the existence of a seemingly satisfactory explanation (left-hand writing), the failure to bring together research in neuropsychology and educational psychology, and the failure to consider the shape and structure of the characters. The present paper remedies this situation by describing a new, comprehensive theory based on recent neuropsychological findings and extensive empirical observations. The theory assumes that a character's orientation, detected in the early visual processing area, is deleted (or made inaccessible) by the mirror generalization process during transfer to memory. Consequently, there is a period, usually around age five, during which children have representations of the characters' shapes but not their orientations. Hence, when asked to write a character, children have to improvise its orientation, and the orientation they choose (implicitly, non-consciously) is often derived from the writing direction in their culture. Introduction: Historical BackgroundCharacter reversal, which results in left-right reversed characters (letters and digits) that appear normal when read in a mirror, is a major component of mirror writing. In the scientific literature, it was first described in 1878 by Buchwald, who reported several cases of character reversal in writing by patients with brain lesions and by healthy individuals, most notably children, nearly all of whom wrote with their left hand [1]. This pioneering study launched a new field of research and triggered numerous reports of mirror writing by both pathological and non-pathological individuals. Less felicitously, Buchwald's implicit suggestion that mirror writing was restricted to people who wrote with their left hand, whether naturally or deliberately, would cloud research for over a century.Erlenmeyer immediately included Buchwald's paper in his book on "Writing", quoting at length the paragraph describing children who mirror wrote with their left hand, but, when alerted to the incorrectness of their writing, wrote correctly with their right hand [2]. Furthermore, by suggesting "abductive left-hand writing" (linkshändige Abductionsschrift in German) as a more appropriate name for "mirror writing", Erlenmeyer reduced mirror writing to a mechanistic result of writing with the left hand: Characters and words are reversed when an individual writes abductively (outwards from the body midline) with the left hand.

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Section: Discussionmentioning

confidence: 95%

Section: Is There a Differentiated Role For The Cerebral Hemispheres?mentioning

confidence: 97%

A Synoptic and Theoretical Account of Character (Digits and Capital Letters) Reversal in Writings by Typically Developing Children

Fischer

Luxembourger

2018

Education Sciences

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“…Literacy-related processing of mirror images (i.e., 180 • reflection around image axes; e.g., d-b) is perplexing because it requires the 'unlearning' 1 of evolutionary-old and cross-species mechanism of mirror invariance, i.e., tendency to process mirror images as equivalent, possibly consequence of convergent evolution by similar ecological demands. Natural objects are often symmetric; hence, mirror-image discrimination would delay recognition (Bornstein, Gross, & Wolf, 1978;Corballis, 2018;Dehaene et al, 2015;Lachmann & van Leeuwen, 2008Logothetis, Pauls, & Poggio, 1995). Investigating it is critical for understanding cultural re-shaping of evolutionarily-inherited cognitive mechanisms.…”

Section: Introductionmentioning

confidence: 99%

The role of the written script in shaping mirror-image discrimination: Evidence from illiterate, Tamil literate, and Tamil-Latin-alphabet bi-literate adults

2021

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Learning a script with mirrored graphs (e.g., d ∕ = b) requires overcoming the evolutionary-old perceptual tendency to process mirror images as equivalent. Thus, breaking mirror invariance offers an important tool for understanding cultural reshaping of evolutionarily ancient cognitive mechanisms. Here we investigated the role of script (i.e., presence vs. absence of mirrored graphs: Latin alphabet vs. Tamil) by revisiting mirror-image processing by illiterate, Tamil monoliterate, and Tamil-Latin-alphabet bi-literate adults. Participants performed two same-different tasks (one orientation-based, another shape-based) on Latin-alphabet letters. Tamil monoliterate were significantly better than illiterate and showed good explicit mirror-image discrimination. However, only biliterate adults fully broke mirror invariance: slower shape-based judgments for mirrored than identical pairs and reduced disadvantage in orientation-based over shape-based judgments of mirrored pairs. These findings suggest learning a script with mirrored graphs is the strongest force for breaking mirror invariance.

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“…These accounts do not clearly differentiate between the confusion of the characters in seeing them and their reversal in writing them. Orton's theory was then mainly improved by Corballis and coworkers [3][4][5]. The double representation, one writing in each hemisphere, offers a simple explanation of confusion between a character and its mirror; that is, the use of the "wrong hemisphere" [6].…”

Section: Introductionmentioning

confidence: 99%

The Battle between the Correct and Mirror Writings of a Digit in Children’s Recognition Memory

Fischer

Luxembourger

2020

Education Sciences

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Recent research into character reversals in writings produced by occidental children has shown that they mainly reverse the left-oriented digits (1, 2, 3, 7, and 9) and therefore appear to apply a right-orienting rule. But do they produce similar reversal errors when asked to recognize the digits? In an experiment, based on eye-tracking observations of 50 children (Mage = 5.4 years), children had to point towards a target digit in a 2 × 2 matrix also containing three distractor digits, one of which was the mirror-reversed writing of the correctly written target digit. This recognition task led to a true “battle” in children’s memory between the two writings of the target digit. This battle is shown in the graphical abstract that represents a heat map from a sub-sample of children (on the left side) and the fixation points map from an individual child (on the right side). Rather than following the predicted right-orienting rule, the children’s responses appeared to be biased towards digits in the right-hand column of the 2 × 2 matrices (when the reversed target digit was not in the same column as the correctly written target digit). As a whole, these findings support the hypotheses that many 4- to 6-year-old’s representations of the digit writings are unoriented in their memory and that these children may adopt different solutions to overcome this lack of orientation depending on whether they write or read.

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Mirror-Image Equivalence and Interhemispheric Mirror-Image Reversal

Cited by 28 publications

References 92 publications

A Synoptic and Theoretical Account of Character (Digits and Capital Letters) Reversal in Writings by Typically Developing Children

A Synoptic and Theoretical Account of Character (Digits and Capital Letters) Reversal in Writings by Typically Developing Children

The role of the written script in shaping mirror-image discrimination: Evidence from illiterate, Tamil literate, and Tamil-Latin-alphabet bi-literate adults

The Battle between the Correct and Mirror Writings of a Digit in Children’s Recognition Memory

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