Depends. To shift to a bigger gear you press the brake handles in, to shift to a smaller ring it was either have another lever just behind the brake lever that you hit with your index finger, OR it will have a lever at the top and inside part of the handle bar you hit with your thumbs. I prefer the former. It's sleek, easy, and I can do any shift from any riding position.
Not sure how much it would cost to go from the thumb shifters to the index ones. I got a allez too and it came with the finger shifters (STI)
Most of my components are tiagra and some are 105, sure can't complain, it's a great first bike!
*note* looking at your picture. It looks like it does not have the finger shifters, though it is hard to tell.
Last edited by Element GT; 07-04-09 at 02:12 AM.