Page 17 - MONSOON EDITION

CURRICULAR ACTIVITIES

7: A HAPPY MAGICAL COINCIDENCE

There are 7 days in a week, 7 colours in a rainbow, 7 notes in a musical scale, there are 7 seas and 7 continents even the
code name for James Bond was 007. We have lived among all these things for such a long time without any explanation for
the one common absurdity that is 7. In fact there is one more place where the number 7 governs the rules but we don't take
notice of it. This was brought to the attention of common people by George Armitage Miller in his book ' The Magical Number
Seven, plus or minus Two.'

According to the author, it is natural if you are having a tough time trying to remember your grocery list or all the names of 12
historical figures no need to despair. Numerous psychological experiments have shown that on an average, the longest
sequence a normal person can recall an immediate task is about seven items. This limit dubbed as the “magical number
seven” which was discovered in the 1950s is the typical capacity of what's called the brain's working memory.

If we consider long term memory as a vast library then the short term memory can be considered as a black board where we
scribble things and erase them as when needed. That part of the brain is involved in activities like following a conversation,
instantaneous calculations, instinctual decisions and copying moves in a workout video. To test these conclusions you can
do a simple activity wherein a friend has to read a list of 12 to 13 random numbers and try to recall as many as possible after
the first read. It is seen that more often, the person will be able to remember 7 or less than 7 words.

The simplest way to explain this process is to imagine the sentence or words as a long input string and the brain as a
processor. As and when the string of inputs gets longer and complicated the processor finds it tougher to comprehend and
reciprocate to it and there comes a limit after which the processor crashes (to put it in a crude way) and there are errors in
the processor. This means that as the number of words or the complexity of the sentence increases it gets exponentially
difficult to recall it and we end up making mistakes. That limit in most humans is 7 (plus or minus 2). Of course since there is
a rule it is accompanied by exceptions in this case in the form of autistic individuals who easily skip past 7 or 8 items and are
able to remember even 50 or 100 random numbers in a single read. They seem to have a stronger processor. So try this
activity at home and who knows you might break the stereotype of 7. Is this just a coincidence or is there truly something
magical about 7 and how it controlled our memory? Who knows, but it is very interesting.

Also, 7 is the smallest happy number. What is a happy number? A happy
number is a number which eventually reaches 1 when replaced by the sum of the
square of each digit. So 7 ^2 = 49 and now square of 4 and 9 respectively is 16
and 81. 81 + 16 = 97. Square of 9 is 81 and square of 7 is 49 and 81+ 49 = 130.
If you repeat this process two more times the final answer will be 1.

So you can see that 7 is a magical number in its own rights and we may have just
scratched the surface yet. If we dip into the calendar we might find a whole new set
of magical properties about 7.

Sources: npr.org , dailymail, insidescience.
Based on the idea of the book 'The Magical Number Seven, Plus Or Minus Two'
written by George Armitage Miller

Written by -
Naman Badiani
Class 11-A
Mathematically Reviewed by
– Ms. Vaishali Lakhlani.
17