Practicing self-control consumes energy

 Practicing self-control consumes real energy  Annotated

While reading is a mental process , it feels like we’re expending more energy avoiding reading than we would to do the reading itself.

 Research led by Roy Baumeister has found that people who’ve resisted eating cookies gave up sooner on a task requiring persistence compared to those who succumbed to temptation and ate the cookies. Other research has associated low blood glucose levels with poor performance on the Stroop task — another task that requires people to avoid reading. Is it literally true that the sugar in our blood fuels our ability to control our impulses?

Matthew Gailliot, along with Baumeister and six other researchers, asked 103 psychology students to fast for three hours before watching a video where they had to resist reading  intermittenty flashing text that appeared in a corner of the screen.. Half the students were told to ignore the words, while the rest weren’t required to exercise any self-control. Blood glucose levels were measured before and after this task. The students exercising self-control had significantly lower glucose levels after watching the movie, while the other students did not. In another experiment, students performed the Stroop task after watching the movie. The students who had to resist reading the words performed significantly worse on the Stroop task; their lower blood glucose levels after watching the movie and avoiding reading seemed to impair performance.

Gaillot’s team repeated these experiments several times, with tasks ranging from avoiding displays of racial prejudice to dealing with thoughts about death. In each case, the results supported the idea that self-control literally relies on glucose. When blood glucose is depleted, we’re less able to exert self-control. The researchers say that the brain has a limited reserve amount of glucose, which allows us to handle the ial task demanding self control, whether it be watching a movie without reading accompanying text, or avoiding fattening snacks. Once that glucose supply is depleted, self control becomes much more difficult, across an array of different tasks.