There has been some interesting work on self-control at Stanford, looking at individual variations and contributing factors. They ran the well-known “marshmallow” experiment, where 4-year-olds were given the following choice: A marshmallow and a bell were put in front of them and they were told that they could eat the marshmallow right away, but the researcher said that he was going to leave the room for a few minutes, and if the kid would wait until he returned the kid could have two marshmallows. Also, while the researcher was out of the room, the kid could ring the bell and the researcher would run right back in and give the kid the one marshmallow, but not two.
So the kid knows that if he waits long enough, he’ll double his take. But only about 30% of the kids could hold out for the full 15 minutes. As researchers followed these kids into adulthood, there was a strong correlation between how much self-control they exhibited in the marshmallow test and subsequent academic success. Those who could wait averaged 210 points higher on the SAT and had few behavior problems and more stable relationships.
As researchers looked for reasons for the individual variation, they found that the level of desire for the marshmallow was the same for “waiters” and “non-waiters”. The main factor seemed to be attention control. Those most likely to wait were those who could employ various strategies to put the object of desire out of mind. The “non-waiters” just fixed their attention on the object and couldn’t break out of its spell.
The age group for these studies was at a transitional development stage of the brain. It’s at about this time that the top portion of the anterior cingulate becomes more active. The anterior cingulate integrates signals from several brain regions, rational and emotional, and is instrumental in formulating behavioral strategies. But the top of the AC listens particularly to the prefrontal cortex, which tips behavior to favor the logical over the emotional.
To what extent this shift happens seems to depend on several inherited and environmental factors. Kids raised in cultures that emphasize self-control have a much easier time with this. The American culture sends very mixed messages concerning self-control. We have our Puritanical streak that values restraint, true, but nowadays that message is overshadowed by constant appeals for instant gratification and self-indulgence. Kids watch a lot of TV, and they get a steady media diet of “you need this and you need it now”.