[Paleopsych] NS: Computer analysis provides Incan string theory

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Computer analysis provides Incan string theory
     * 19:00 11 August 2005
     * Will Knight

Computer analysis reveals that information is
collated from some Khipu into high level ones

The mystery surrounding a cryptic string-based communication system used by 
ancient Incan administrators may at last be unravelling, thanks to computer 
analysis of hundreds of different knotted bundles.

The discovery provides a tantalising glimpse of bureaucracy in the Andean 
empire and may, for the first time, also reveal an Incan word written in 
string.

Woven from cotton, llama or alpaca wool, the mysterious string
bundles - known as Khipu - consist of a single strand from which
dangle up to thousands of subsidiary strings, each featuring a
bewildering array of knots. Of the 600 or so Khipu that have been
found, most date from between 1400 AD and 1500 AD. However, a few
are thought to be about 1000 years old.

Spanish colonial documents suggest that Khipu were in some way used
to keep records and communicate messages. Yet how the cords were
used to convey useful information has puzzled generations of experts.

Now, anthropologist Gary Urton and mathematician Carrie Brezine at
Harvard University, Massachusetts, US, think they may have begun
unravelling the knotty code. The pair built a searchable database
containing key information about Khipu strings, such as the number
and position of subsidiary strings and the number and position of
knots tied in them.

The pair then used this database to search for similarities between
21 Khipus discovered in 1956 at the key Incan administrative base
of Puruchuco, near modern day Lima in Peru. Superficial similarities
suggested that the Khipu could be connected but the database revealed
a crucial mathematical bond - the data represented by subsidiary
strands on some of Khipu could be combined to create the strands
found on more complex ones.

This suggests the Khipu were used to collate information from
different parts of the empire, which stretched for more than 5500
kilometres.  Brezine used the mathematical software package Mathematica
to scour the database for other mathematical links - and found
several.

"Local accountants would forward information on accomplished tasks
upward through the hierarchy, with information at each successive
level representing the summation of accounts from the levels below,"
Urton says. "This communication was used to record the information
deemed most important to the state, which often included accounting
and other data related to censuses, finances and the military."

And Urton and Brezine go a step further. Given that the Puruchuco
strings may represent collations of data different regions, they
suggest that a characteristic figure-of-eight knot found on all of
the 21 Puruchuco strings may represent the place itself. If so, it
would be the first word to ever be extracted from an Incan Khipu.

Completely deciphering the Khipu may never be possible, Urton says,
but further analysis of the Khipu database might reveal other details
of life. New archaeological discoveries could also throw up some
more surprises, Urton told New Scientist.