Researchers have trained rhesus macaque monkeys to recognize two sets of symbols, with 26 symbols in each set. And the monkeys demonstrated an ability to add them together!

English chemist-physicist John Dalton starts using symbols to represent the atoms of different elements.

Using Symbols As Nurturing Tools By Tatiana Morales June 13, 2003 / 1:07 PM EDT / CBS Most parents strive to provide a nurturing home environment, but achieving that goal can be challenge.

It has been long thought that one of the characteristics that makes humans unique is our ability to learn and manipulate symbols for communication. However, this notion is starting to slowly unravel.