Someone did a study and found that people assume that they are supposed to eat whatever is put in front of them, regardless of how big the plate is or how much food is on it.
If you're used to eating like there's no tomorrow, then finding your satiation point won't magically happen. You may actually have to practice stopping eating and managing portions or amounts for awhile before you can find it.
My satiation point now, having lost weight, is much lower than it used to be. In the past, I would have to be stuffed before I stopped eating. I was eating to repeat the taste, repeat the taste... Once I started seriously stopping when I had eaten the portion I had allotted myself, I discovered over time that I felt satisfied even though I was not stuffed--and more amazing, I felt full with less food. It has something to do with receptors in the stomach.
This is one reason I don't have "cheats" where I just pig out. It's the wrong model for me. Plus I list absolutely everything I eat, because my body counts it all.
I also have found that it's not necessary to keep on repeating the taste--at least with most foods. Some I just have to stay away from or make sure I have a limited amount available--like ice cream. I will eat all there is.
Like Spinymouse, I find it helps to be mindful, to pay attention to eating when I'm eating, and to go slowly.
It's an interesting thing--satiation--and it does change if you stay on plan!
Jay