(CNN) -- Humans have been doodling in snow, in sand and on cave walls for more than 30,000 years.
George Washington, Thomas Edison, John F. Kennedy, Lyndon Johnson, Ronald Reagan and Vladimir Nabokov were doodlers. Bill Gates and Frank Gehry are among today's active doodlers.
Yet most of us haven't reflected on why we feel compelled to draw.
In fact, many parts of our society -- including businesses, schools and colleges -- frown on doodling and consider it a waste of time. While we can't overcome cultural biases overnight, we can certainly ask a relevant question: Why is doodling so universal? What is doodling doing for us?