I was sitting in a restaurant when I realized that it was relatively easy to read this list of a few locations in inverted English script. It made me curious about how it is possible to read this with such ease. It also seems that since these names may be familiar, I might just be engaging in "inverted image" recognition since the normal 'whole image' (e.g. Boston) seems so familiar. Perhaps if these locations were not familiar, it would be slightly harder to process the text.

I was conflicted between posting this in this or in the Linguistics StackExchange but felt that this would be more relevant since there will be multiple perspectives from those interested in neuroscience, psycholinguistics, machine learning and natural-language processing.

A search on the internet seemed to give a lot of instances of the freak-phenomenon of 'mirror writing' and the well-known phenomenon of irrelevance of spelling in comprehension. Furthermore, it is important to notice that this is different from writing of those who are diagnosed with Dyslexia who process language differently (the writing is whole-wise flipped as opposed to individually). However, there seemed to be a dearth of information on this topic in particular. Of course, I am not interested in one-word instances, another example would be like this.

My questions are :-

Are there any good experiments on the phenomenon of processing inverted text ?

Although very little is understood about the neuroscience of language, are there any neurolinguistic perspectives on this phenomenon?

What are the underlying mechanisms hypothesized by the quoted papers in processing such text?

Does there seem to be any evidence of rule-based processing
(e.g. flipping each letter individually)

Instance of Inverted English Script


1 Answer 1


Are there any good experiments on the phenomenon of processing inverted text?

This is probably the place to start:

Poldrack, Russell A., et al. "The neural basis of visual skill learning: an fMRI study of mirror reading." Cerebral Cortex 8.1 (1998): 1-10. APA

What are the underlying mechanisms hypothesized by the quoted papers in processing such text?

"Multiple regions in the occipital lobe, inferior temporal cortex, superior parietal cortex and cerebellum were involved in the reading of mirror-reversed compared to normally oriented text. For novel stimuli, skilled mirror-reading was associated with decreased activation in the right superior parietal cortex and posterior occipital regions and increased activation in the left inferior temporal lobe. These results suggest that learning to read mirror-reversed text involves a progression from visuospatial transformation to direct recognition of transformed letters. Reading practiced, relative to unpracticed, stimuli was associated with decreased activation in occipital visual cortices, inferior temporal cortex and superior parietal cortex and increased activation in occipito-parietal and lateral temporal regions. By examining skill learning and item-specific repetition priming in the same task, this study demonstrates that both of these forms of learning exhibit shifts in the set of neural structures that contribute to performance."

Does there seem to be any evidence of rule-based processing?


"Mirror-reading skill is letter-specific rather than being a general visual transformation skill"

  • $\begingroup$ Can you elaborate on your last answer about rule-based processing. $\endgroup$
    – Vakalate
    Oct 7, 2015 at 0:31
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    $\begingroup$ Based on this paper (you can read it online for free), the whole process requires effortful letter inversion prior to the comprehension of the word. So, it's pretty much as you have proposed: "flipping each letter individually". $\endgroup$
    – Izhaki
    Oct 7, 2015 at 0:44
  • $\begingroup$ I used to work for Oxfam. One of my jobs was to sort though about 2-4 tonnes of books once a week. I had to sort them by both condition and subject. Because there were so many books, I didn't have time to pick each one up carefully and inspect it. It got to the stage where I had usually already categorised the book before my hand reached it. The books were in a huge cage/ basket and were all jumbled up. I very quickly learned to read upside down and at weird angles. After that job I always had problems when I came up against glass doors, or when reading instructions written for pedestrians ... $\endgroup$ Dec 21, 2015 at 15:59
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    $\begingroup$ .... written on the opposite side of the road. My brain wouldn't recognise that the writing was mirror imaged or upside down. So I'd regularly read the signs meant for people on the other side of the door as if they were for me. I'd also get majorly confused by things written on the other side of the road. I strongly suspect that the "effortfulness" falls away very rapidly with a relatively small amount of exposure to having to do it. $\endgroup$ Dec 21, 2015 at 16:02

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