I recently was reading about how children's ability to delay gratification corellated with their prospects for success later in life. The article referenced "The Marshmallow Test" for children, so I conducted my own informal research study on the back deck with the kids.
Gracie, Gemma, Luke, Marshall and Nyla were each given one large marshmallow with these instructions. "You may eat this marshmallow at any time. However, if you can wait for five minutes before you eat it, I will give you a second marshmallow."
Gracie, 12: walked off to visit with a friend and came back 5 minutes later. No sweat.
Gemma, 10: sat still and tried to get Luke to eat his marshmallow.
Luke, 8: stared at his marshmallow and fought the good fight against his instincts.
Marshall, 5: held his marshmallow in his hands and licked his fingers--but didn't take a bite.
Nyla, 3: Nyla waited mere miliseconds before shoving the entire marshmallow in her mouth. With gusto.
After five minutes, I announced, "Congratulations to those of you who were able to wait! You may have your marshmallow AND here's a second one to enjoy. Don't tell your mother that I gave you two large marshmallows in the name of science, please."
"Nyla, you don't get a second marshmallow because..." Like a lioness after its prey, Nyla LEAPED up on the deck table and crossed it as she lunged at my throat. "I WANT A MARSHMALLOW!!!!!! I WANT A MARSHMALLOW!!!!
Study conclusion: Delayed gratification skills are helpful but not necessary to get marshmallows when the subject can take the entire bag using hostile force. :)