# Polynesians Developed a Binary Number System 600 Years Ago

Humans might be natural-born computers. Babies, we’ve discovered, are born to count, and now historical analysis suggests that hundreds of years ago, Polynesians on the island of Mangareva counted with a binary system that’s strikingly similar to that used by computers today.

Psychologists Andrea Bender and Sieghard Beller of the University of Bergen in Norway report that the island’s inhabitants needed a number system to log transactions from trade and tributes made to chieftans. So they developed a sort of hybrid approach to keep track of it all.

A binary system helped Mangarevans navigate murky mathematical waters long before Europeans put it into practice.

Philip Ball, writing for Nature News:

They find that the former Mangarevans combined base-10 representation with a binary system. They had number words for 1 to 10, and then for 10 multiplied by several powers of 2. The word takau (which Bender and Beller denote as K) means 10; paua (P) means 20; tataua (T) is 40; and varu (V) stands for 80. In this notation, for example, 70 is TPK and 57 is TK7.

Bender and Beller show that this system retains the key arithmetical simplifications of true binary, in that you don’t need to memorize lots of number facts but follow only a few simple rules, such as 2 × K = P and 2 × P = T.

Some cognitive scientists argue this ancient application of binary isn’t unique; the 64 hexagrams in the Chinese text I Ching, for example, have a binary arrangement. Still, it’s exciting to see yet another example of the way different cultures arrive at a cognitive commonality.