jackson has been shaking his head from side to side for a couple of months for no particular reason, he just does it out of the blue. i looked it up in our baby book and it says that if they arent using it as a signal it basicallly means that they have discovered they have got rythm!! now i can see that he does it more when he hears sounds or music, or has a rattle or noisy toy in his hand. his daddy is a drummer, so perhaps we have a born musician on our hands!!