I have never seen a country with so many people talking to themselves like here in Japan. They even have a compound noun for the action as in the photo I posted above: 独り言（hitorigoto）.
When I first came to Japan, seeing grannies pushing carts around the supermarkets and murmuring their consideration out gave me creeps. After all these years, I got so much used to it that sometimes at work I happen to mumble to myself.
There goes a theory, as my friend told me today, that as one person has to much to think at the same time and cannot manage it, the thoughts overflow out of his mouth into words. Like a computer, he continued, when it uses up all its physical memory, it resorts to the virtual memory on a hard disk. In other words, the data overflow into storable electronic bits on to the hard disk. Similarly, a person’s overflowing thoughts come out in the shape of words.
I am very fond of this comparison. We human create computers and we use computer processes to explain human’s behaviors. Both the irony and the uniqueness of this explanation charm me with this little elation which still tinkles at the back of my head.