Which is Better? Instant Gratification, or Long Term Rewards?

My boys always discover ridiculous videos to entertain our family, like Good Mythical Morning with Rhett and Link or Dude Perfect. Well, one time they found this video called Brain Games. The producers of the show conducted an experiment with nine elementary-aged kids. They were stuck in individual rooms, each sitting at a table with a plate of irresistible, fluffy, pink cotton candy. Here were their instructions. “You can eat this now, or wait fifteen minutes and get two more cotton candy balls just like this one.”