aged about 18 months old, my parents were at a loss to know how to entertain me. I diodn't really like toys. I did love clocks. In fact, whnever i saw one i would scream "Tic Toc" at the top of my voice in excitement. One day they took me to London Zoo. After about 2 hours of looking at all the animals (in silence), I suddenly saw the Zoo clock....i errupted into an enormous and iconic "Tic Toc" tirade.
So, i guess i started at 18 months.