Going through John Lehrer's text of "Don't", I see that he uses dialogue to further explain the theory. He is able to give the point of view of both the testee and the tester. Mischel, who is the mastermind behind the experiment, was saying that "What we're really measuring with the marshmallows isn't will power or self control. It's much more important than that. This task forces kids to find a way to make the situation work for them. They want the second marshmallow, but how can they get it? We can't control the world, but we can control how we think about it." John has put this in here because it gives you the real meaning behind the theories and the statistics. It shows how passionate Mischel was about this project. The dialogue also lets you see what the children (at the time) were thinking as they were contemplating whether to eat the marshmallow or not. One of the children Craig said that when he realized their was no adult in there to see him he took a marshmallow. This helps Mischel and the reader to see what the reason behind not waiting to eat the marshmallow besides the fact that they wanted it.
Another tool that John uses in his essay is giving a short introduction or biography of the characters in the story. He describes Mischel with a shaved head and brooklyn accent. Telling us that Mischel acts out his sentences behaving like a four year old. When he acted this way Mischel said it helped to understand the children. Giving little biographies and introductions helps set the mood and lets you imagine what and how the process of the experiment looked.