Yup, partially comes from there and partially from a lot of the other research on willpower that has been coming out lately. While some of it has proved to be a bit overstated (at least in the press) and there probably isn't literally a such thing as "cognitive energy", I find it a helpful metaphor. Once you realize that you and others have a finite amount of it, you can start thinking clearly about how you spend it and why. The concept in your head doesn't have to be a 100% accurate reflection of reality to produce useful changes.