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Number-form synesthesia

Also occasionally called number-space synesthesia

A type of spatial sequence synesthesia

(Image: Ailsa in Ailsa Brims Fine Art)

People with this type of synesthesia perceive numbers as a sequence visualised spatially, around them or in front of them. The spatial positioning is highly consistent and tends not to vary throughout the synesthete’s lifetime. For many of these people, each number also has its own colour (so number-form coexists with grapheme-colour synesthesia in this case), or their number maps have shading effects. These synesthetes frequently visualise the numbers spatially in relation to themselves, with a perspective that varies according to the number they have in mind at any given time. The maps are three-dimensional and assume many different forms: they can be straight or curving, with one or more changes of direction, with right angles, peaks and dips, spirals, zigzags, steps or ladder-like structures, going from right to left or vice versa, climbing up or disappearing on the horizon as the numbers get larger, and they may look tidy and well-organised or appear chaotic, only making sense to their “owner”. In any case, it can safely be said that there are as many spatial numerical maps as there are number-form synesthetes, as this type of synesthesia is just as idiosyncratic as any other.

(Image: Sarah, in the blog Terra Nomad.)

What percentage of synesthetes have this specific subtype? There do not appear to be any studies giving a conclusive number, but it probably occurs in the majority of people who have calendar synesthesia (estimated at 20%, N. Sagiv et al, 2005) and also in some others who do not have the calendar type, so it is likely to be relatively common.  

Projector synesthetes, who are a minority, see their sequences physically in the space around them, while associators perceive a well-defined and consistent map in their mind’s eye, always present in their lives.

(Image: from the book Des Phénomènes de Synopsie by Théodore Flournoy, 1893, p163.)


Having this type of synesthesia often helps the synesthete to perform mental calculations and these people sometimes excel at mathematics, as they can easily navigate through their visual numbers, handling and remembering them at will.

(Image: Francis Galton, 1881)


All the above examples are for natural numbers, but there are also synesthetes with mental maps for other numerical sequences: age, height and/or weight measurements, temperatures (meteorological or body temperature), clothes sizes, shoe sizes, salaries and so on.

(Images: Weight in lbs and people’s ages, by Rebecca Schulz Kluchnyk, posted to the Facebook group Synesthesia. 2020.)


Go to the page on spatial sequence synesthesia in general

Go to the page on alphabet-form synesthesia


4 comments:

  1. Re: Sarah, Terra Nomad photo above. Similar to mine and I remember forming mine around three years of age. Note, we are first taught numbers 1-10, then 11-20, then 21-100. Note the turns at each new lesson. I remember these lessons and how I responded to them. I was excited to learn and one to ten was wonderful! But the next day at school, I learned there were more! My 1-10 extended straight up and away from me, so I just continued the 11-20 on up. But! The next day! Even more! 21-100! I had to make a sharp right turn, as there were just sooo many numbers! So 21-100 went right. As you might imagine, there were more to learn. At 100, I made another right turn up to 1000. At that point, the numbers became more nebulous and I allowed them to continue on into infinity. I have many of these spacial forms, but number and letter are the only ones I remember forming in my mind at an early age.

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  2. My number form is very similar to the picture at the very top of this site. 1 ist at 3 o'clock and the numbers go clockwise until 12 at 11 o'clock, then it goes on diagonally to the top left until infinity, with a few slight kinks at 100, 1000... negative numbers go diagonally in the other direction. I always thought everyone sees numbers that way, because its so similar to a clock. Today I learned its synaesthesia...

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  3. I didn’t realize this was out of the ordinary until this year, and I’m 56. I got a puzzled look when I asked how somebody saw numbers in their head.

    I also didn’t know there was a term for it until today. I see whole numbers climbing up like steps, angling a bit for each group of ten. I see years and decades, starting this year going down to the left and then turning to the left a little bit more to the left each decade then right and down at about 1970.

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  4. Mine are similar to some of these - somewhat like a clockface for one to 12, then off to the left for 13-20. But then the twenties, thirties etc are also similar clock face like. And if I zoom out, the whole lot 1-100 are on a semi circular path, as is 100-1000. But I know mine are not 2D - 20 is higher than 12, 100 higher than 20. And mine include negative numbers, and there is a space for irrational numbers (eg square root of -1), not that I can see them, just a space for them

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