I read up on the subject of gestures, and here's a nice find that I already alluded to:
Desmond Morris, Bodytalk, 1994
Head Toss
Meaning: No!
Action: The head is tilted vigorously backwards.
Background: Most people, throughout the world, shake the head from side to side when saying "No!", but in a few regions there is an alternative head movement, the Head Toss. Both appear to have originated from a childhood action. When an infant has had enough to eat, but the parent insists in trying to push one more spoonful into its mouth, one of two reactions may occur. The child may either twist the head sideways, or tilt it upwards, in an attempt to reject the food offering. In other words, moving the head smartly sideways or upwards means 'No!' for the infant. The sideways head movement has developed into the familiar, negative Head Shake in most cultures, but in a few cases it is the other action, the upward tilt of the head, that has become the negative Head Toss.
Locality: This action has been observed in most Arab cultures. In Europe it is usually known as the 'Greek No' and has spread from there to modern-day Turkey, Corfu, Malta, Sicily and the southern parts of Italy. Of particular interest is the fact that, in Italy, its use only extends as far north as the Massico range of mountains between Naples and Rome. This is the point at which the Greek colonization of Italy stopped two and a half thousand years ago. This 'gesture barrier' reveals that ancient forms of body language can be extremely conservative and show little change over the centuries, despite the mobility of modern living.