抄书

the most surprising discovery made by his group shows, as he puts it, that the idea of mental energy is more than a mere metaphor. the nervous system consumes more glucose than most other parts of the body, and effortful mental activity involved in difficult cognitive in the currency of glucose. when you are actively involved in difficult cognitive reasoning or engaged in a task that requires self-control, your blood glucose level drops. the effect is analogous to a runner who draws down glucose stored in her muscles during a sprint. the bold implication of this idea is that the effects of ego depletion could be undone by ingesting glucose, and he and his colleagues have confirmed this hypothesis in several experiments.