I just read a book called "The Mind in The Cave" of David Lewis-Williams about prehistoric people and cave wall art. The author says that the main difference between Neanderthal's and modern man's mind shows in modern man's ability to paint images. Can we therefore conclude that "paintbrush is a yardstick of civilization"?
http://photos1.hi5.com/0010/080/197/31D209080197-02.jpg
http://photos1.hi5.com/0010/080/197/31D209080197-02.jpg