Shakuntala Devi – The Human Computer

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Source-Scientist Prateek Kumar Das
Source-Scientist Prateek Kumar Das

Shakuntala Devi was born on November 4, 1929 in Bangalore, India to an orthodox   Brahmin kannad family. Her father worked as a trapeze artist, lion tamer, tightrope walker and magician.

Known For

Shakuntala Devi, one of the world’s most prodigious mental calculators on record, past or present, is especially remarkable for the incredible speed with which she performed mental calculations on very large numbers. Though Shakuntala Devi did not received any formal education but she possessed extraordinary talent and magnificent brain event faster than a super computer of her time. She had an amazing ability to complete the most complex mathematical calculations in double quick time that she became known as “The human computer”.

She was about 3 years of age and playing cards with her father when he discovered that she was a mathematical prodigy with an uncanny ability to memorize numbers. By the age of 5, she had become an expert at solving math problems. After having seen the exceptional skills and potential her father decided to left the circus and took her on road shows that displayed her ability at large calculation and Shakuntala Devi  did all this without any formal education. At that time she was the only source of income her family. At the age of 6, she presented her first major show at the University of Mysore, and this was the beginning of the marathon of public performances.”

In 1944, Ms.Devi departed to London with her father and started her performances in whole Europe in 1950. When she appeared on the BBC and her answer to a difficult calculation was different from the interviewer’s answer.  But later on it turned out that she was right. Similarly, at the University of Rome, one of her answers to a problem was found to be wrong, until the experts re-examined their own calculations. Lets see few more examples of her brilliance-

An article in the New York Times (November 10, 1976, cited in Smith, 1983, p. 306) reported that Shakuntala Devi added the following four numbers and multiplied the result by 9,878 to get the correct answer  i.e 5,559,369,456,432 in less than 20 seconds. The four numbers are- 25,842,278111,201,721370,247,83055,511,315. The article also said that, “She could give you the cube root of 188,132,517 – or almost any other number – in the time it took to ask the question. If you gave her any date in the last century, she would tell you what day of the week it fell on.”

In 1977, at Southern Methodist University in Dallas, she extracted the 23rd root of a 201-digit number in 50 seconds, beating a Univac computer, which took 62 seconds in solving the same problem. Her answer 546,372,891 was confirmed by calculations done at the U.S. Bureau of Standards by the Univac 1101 computer, for which a special program had to be written to perform such a large calculation.

In 1980, she correctly multiplied two 13-digit numbers in only 28 seconds at the Imperial College in London. Numbers were randomly picked by the computer department of college. The number was 7,686,369,774,870 and 2,465,099,745,779. After 28 seconds she correctly answered “18,947,668,177,995,426,462,773,730”, a feat that earned her a place in the 1982 edition of the Guinness Book of Records.

In 1988, Shakuntala Devi visited San Francisco,  United States, where the educational psychologist Professor Arthur Jensen tried to unlock the secret of her abilities. At Stanford University Shakuntala Devi, in a colorful silk sari, sat at a table in front of the blackboard in a lecture hall filled with mathematicians, engineers, and computer experts, who had come with their electronic calculators or printouts of large problems that had been submitted to the University’s main-frame computer.

When volunteers wrote problems on a blackboard, Shakuntala Devi would turn around, stare at the problem and come up with the right answer, always in less than a minute. Arthur Jensen Seated in the first row nearest to Devi, was equipped with a HP computer and a notebook with his wife  holding a stopwatch to measure Devi’s solution times.  According to Jensen , in a research study published in the journal Intelligence in 1990: “Devi solved most of the problems faster than I was able to copy them in my notebook.”
When Jensen handed  her two problems, the cube root of 61,629,875, and the seventh root of 170,859,375. Shakuntala Devi gave the correct answers – 395 and 15 – even before Jensen’s wife could start the stopwatch.
Then to “warm up” she requested a large number of cube root problems, that is, extracting the cube roots of large numbers, mostly in the millions, hundreds of millions, and trillions. The average time Devi took for extracting all of these cube roots was just 6 seconds, with a range of 2 to 10 s. Some examples are:
3√95,443,993                       Ans. 457                           Time: 2 s  
3√204,336,469                     Ans. 589                           Time: 5 s
3√2,373,927,704                 Ans. 1,334                        Time: 10 s

Then Devi took on more obviously difficult problems. For example:
8√20,047,612,231,936         Ans. 46                               Time: 10 s
Ans. 46,295                   Time: 40 s

The demonstration lasted almost 90 min. In all of the above examples the numbers have here been marked off with commas, as is customary, for ease of reading. But Devi refused to accept large numbers marked off with commas, claiming that the commas break up a number artificially. For Devi, grouping the numbers in triplets by commas hinders the solution process. Hence the large numbers written on the blackboard for Devi were always strings of equally spaced digits, ungrouped in any fashion. A given large number, as she takes it in, rather automatically “falls apart” in its own way and the correct answer simply “falls out.” Apparently she does not apply a standard algorithm uniformly to every problem of a certain type, such as square roots, or cube roots, or powers. Each number uniquely dictates its own solution. so to speak. Hence the presence of commas only interferes with the “natural” (and virtually automatic) dissolution of the number in Devi’s mind.

Other literary Work

Devi wrote a number of books, including novels and non-fiction texts about mathematics, puzzles, and astrology. She also wrote what is considered the first study of homosexuality in India; it treated homosexuality in an understanding light and is considered pioneering.