Phatcat that is some good info, that does seem like logical info, especially coming from webMD. However if you do a search you will find lots and LOTS of conflicting info on the subject. Many people say yes, many people say no. I DID find a happy medium though, and that is this:
The stomach cannot shrink past its original size, however it can expand greatly, and, like a muscle, the more it gets worked out (eating a lot), it gets used to expanding. When it is more used to expanding it leaves the body hungry for more food because its always expecting a larger meal, ready to expand to make room for more.
If you begin to eat less however, the stomach will get used to not having to expand all the time, and won't start expanding as soon as you start to eat. This leaves you with a full stomach quicker, as the stomach will want to stay at it's original size.
I don't know for sure if this is fully true, but it seems that there is no 100% answer on the subject. So it CAN expand and contract, but being full or hungry relies on if it is more used to expanding all the time from over eating, or being contracted most of the time because of smaller/more average meals.