Something you can try to do, is give them their food at the same time. Eat your food slowly, giving them plenty of time to eat theirs. If they sit there and stare at you the whole time instead of eating their food, when you are done, put their food away and don't give it to them for a while. It will teach them: If you don't eat your food right away, you have to wait until the next chance to eat it.
When they start to learn, and eat their food at the right time, slip a little something into ther bowls for a prize.