I think humans have a compulsion to put things on their heads. Putting it on your head is fun! And, it provides a whole new sensory experience. Wearing a hat changes the weight and balance of your head, it does interesting things to peripheral vision if the object comes low enough. I've been a nanny and a preschool teacher and experience tells me it's a weird little human drive to put stuff on your head. I loved it when the kids would put purses on their heads as 'helmets'. Other things include books, pots, buckets, blankets, boots, and even chairs. Hilarity!