The keys to success have finally been revealed by just one experiment done by psychologist Walter Mischel in the late 1960s to early 1970s. Walter Mischel was a professor at Stanford University. In the experiment, a child was offered a choice between one small reward provided immediately or two small rewards if they waited for a short period, approximately 15 minutes, during which the tester left the room and then returned. (The reward was sometimes a marshmallow, but often a cookie or a pretzel)
If you're still confused on how the experiment was done, watch this video and notice the reactions of the kids in the experiment:
See how the kids really struggle very hard to resist the temptation of eating that one marshmallow just to get another one if they wait patiently.
Some parts of the video were really funny looking at the kids faces of how they wait ......