He contends that glucose role in increasing self-control is exerted by signalling high short-term resource availability, a stable environment, and thus low opportunity costs—but he doesn’t expect this effect to hold in the long-term. He predicts that unconscious signals of a stable environment will increase self-control, which helps explains why high social-economic status correlates strongly with self-control.
Seems related to http://en.wikipedia.org/wiki/Broaden-and-build