A Compassionate "Human Computer", RIP
April 23, 2013 10:49 AM   Subscribe

Shakuntala Devi, the Indian "human computer," passed away on Sunday. The NY Times first did a profile on her when she visited the US in 1976, during which she computed the cube root of a 9 digit integer in her head, but could not remember that she had been to the US once before -- over 20 years prior. Bob Bemer (inventor of the Escape key previously) remembers meeting her in 1953 on the TV show You Asked For It (which had previously featured a race between an abacus and a calculator). Psychologist Arthur Jensen (who did controversial research on race and IQ) wrote a paper on Shakuntala's exceptional ability in 1990. Shakuntala made her living as an astrologer and authored numerous books mostly on mathematical puzzles and tricks, but also The World of Homosexuals (1977), one of the earliest ethnographic studies of gay people in India. Specifically about gays in her hometown of Bangalore, Shakuntala called for "not only the decriminalisation of homosexuality in India, but also its 'full and complete acceptance' by the heterosexual population so that the Indian homosexual may lead a dignified and secure life."
posted by bluefly (28 comments total) 31 users marked this as a favorite
posted by MisantropicPainforest at 11:12 AM on April 23, 2013

. × 916748676920039158098660927585380162483106680144308622407126516427934657040867096593279205767480806790022783016354924852380335745316935111903596577547340075681688305 620821016129132845564805780158806771
posted by mrzer0 at 11:15 AM on April 23, 2013 [3 favorites]

Fascinating, thanks.

Parting notes: human computers aren't novel, but her skill is beyond what the vast majority of human computers were doing before the wide-spread availability.

Her book, Figuring the Joy of Numbers, is available as a preview on Google books. In it, she offers some methods and tricks for quickly process calculations in your head, or with limited use of pencil and paper.
posted by filthy light thief at 11:56 AM on April 23, 2013 [1 favorite]

Wow. I'm shocked that this is the first I've heard of Devi and I'm sorry it had to be through an obit post. Still, grateful to have had the chance to read about her.

posted by en forme de poire at 11:56 AM on April 23, 2013

Etymologically, "human computer" is like "acoustic guitar" or "analogue clock" or "snail mail" or "manual transmission"
posted by straight at 12:01 PM on April 23, 2013 [6 favorites]

posted by Renoroc at 12:20 PM on April 23, 2013

posted by infini at 12:24 PM on April 23, 2013

posted by madcaptenor at 12:36 PM on April 23, 2013

Her book, Figuring the Joy of Numbers, is available as a preview on Google books. In it, she offers some methods and tricks for quickly process calculations in your head, or with limited use of pencil and paper.

That book is really neat; thanks for linking. From looking through it, she seems to have had really good pattern memory and recognition skills when it comes to arithmetic.

Also, if you only read one link from the post, I suggest the Jensen paper. The descriptions of both her ability and her personality/background in the beginning of the paper are super interesting.
posted by bluefly at 12:51 PM on April 23, 2013

She also authored/edited a book of puzzles. The kind of puzzles that used to be the norm in IT interviews. I am quite certain that every Indian IT guy has gone through the book and is thankful to her for his first job at least.
posted by vidur at 1:11 PM on April 23, 2013

posted by peacheater at 4:42 PM on April 23, 2013

Indians and math - Bose, Chandrasekhar, Ramunajan, Brahmagupta and now Shakuntala Devi.

posted by marienbad at 6:00 PM on April 23, 2013

made her living as an astrologer

Which in itself is a feat of legerdemain.
posted by Twang at 7:30 PM on April 23, 2013

Sorry to hear she passed. I had her book "Figuring: The Joy of Numbers' as a kid. (Imagine how popular that made me!) Whatever skill/talent she has, I've got a smattering. Let's say the average person is at 1, she's at 85, then I'm at about a 6 or a 7. (If you're wondering what 100 corresponds to, it's Ramanujan.)

It's kind of fun in that certain numbers, or patterns of operations on numbers, are like old friends. So when you see them in the wild you think "Oh, hey, there's 13 ✕ 17 again." I'm pretty sure I got some stuff from her book, but it quickly becomes clear that she just has a staggeringly huge memory, and even knowing how she did things you still couldn't do them yourself.

(That's a decimal point, not a period.)
posted by benito.strauss at 8:14 PM on April 23, 2013

If you're not good at arithmetic then some apparently difficult problems are actually rather easy. Consider the cube root of 2,373,927,704 (which she calculated in 10 seconds). I presume that she had memorised a table of logarithms to, say, three decimal places. Log 2,373,927,704 (base 10) rounded down is 9.375. Divide that by three, the answer is 3.125. The antilog of that is 1,333.5 and since we rounded down before we round it up to 1,334 - which is the correct answer.

So yes, she was very good at arithmetic, but this article comes off like some rube describing a magic act. How did he cut that lady in half? Where did the pigeon come from? It's amazing! Well, no, you just need to know how to do it and practise a lot.
posted by Joe in Australia at 8:33 PM on April 23, 2013

That should be "if you ARE good at arithmetic ...". Apparently if you're not good at words then mumble mumble mumble.
posted by Joe in Australia at 8:44 PM on April 23, 2013

Joe in Australia: Isn't it kind of like a magic trick then?

(In fact mentalism often uses very specific memory tricks to facilitate the effects).
posted by el io at 9:36 PM on April 23, 2013

I suppose you could call this a variety of mentalism, yes, and Jenken's study would have been a lot better if he had approached it from that angle. I have to stress that she was obviously very, very good at what she did - but there's no reason to think that she was born with it the ability, any more than Penn and Teller were born with theirs.
posted by Joe in Australia at 10:46 PM on April 23, 2013

So the kind of tricks her book had was this: You don't need to sweat the last digit when taking the cube root, because the last digit of the cube uniquely determines the last digit of the root (so long as you know you're dealing with integers).
It's a trick (i.e. not a general procedure) because it just happens to work for cubes, but not square, and relies on the number being a perfect cube. Check it out:
last digit of number - last digit of cube
1 - 1
2 - 8
3 - 7
4 - 4
5 - 5
6 - 6
7 - 3
8 - 2
9 - 9
0 - 0
So for the example given we already know that the final digit is going to be four.

It's also interesting to think about the fact that it took 10 seconds. If she was taking logarithms she could have done that calculation in 3-4 seconds. Unless her internal table of logarithms was memorized in a way where it took 5 seconds to look up a number. That'd be different from the way most of us memorize something, where we generally either know it or don't know it.

Also, she must have some other methods in her bag, when you consider this picture of her taking the 23rd root of a 201-digit number.
posted by benito.strauss at 10:55 PM on April 23, 2013

Very interesting post - thanks!
posted by Dr. Wu at 7:26 AM on April 24, 2013 [1 favorite]

I'm a little curious as to why or how they chose that particular 201 digit number, which is 369 × 2023603323.
posted by Rhomboid at 8:35 AM on April 24, 2013

Hmm, I can't think of how that would make it easier. If all the factors were small numbers, she could just keep factoring out 2s and 3s and 7s and keep track of whether there where 23, 46, or 69 ..... of each factor. But that second factor is still 168 digits. Amazing.
posted by benito.strauss at 10:01 AM on April 24, 2013

I can't see that picture but I think this must be the one you're referring to. "Joy of numbers", indeed.
posted by Joe in Australia at 5:52 PM on April 24, 2013 [2 favorites]

Yeah, that's what I was trying to link to. Thanks, looks like my link went bad. I'd love to know what was going on in her mind in that picture.
posted by benito.strauss at 10:17 PM on April 24, 2013

Oh good lord *sinks down on knees*

Contrast that to Shakuntala’s list of reasons to take an interest in math, enumerated in her book Mathability: Awaken the Math Genius in Your Child. Here are just three:
1) “It gives you a purpose, an aim, a focus that insures you against restlessness.”
2) “It makes you regard yourself with greater respect and in turn invokes respect from others around you.”
3) “It makes you more aware, more alert, more keen because it is a constant source of inspiration.”

I just recognized Mrs Narasimhan who embodied these principles so much that would routinely recieve results 100% and A's in GCE O Levels.

posted by infini at 9:59 PM on April 25, 2013 [1 favorite]

Now if I flunked my maths straight throughout Engineering school is due to switching between the British and the American system of teaching mathematics. How can you learn Algebra in the absence of Geometry?
posted by infini at 10:01 PM on April 25, 2013

This website has some interesting PDFs on mental arithmetic.
posted by Joe in Australia at 10:41 PM on April 28, 2013 [1 favorite]

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