(CNN)The premise is simple: You can eat one marshmallow now or, if you can wait, you get to eat two marshmallows later.
It's an experiment in self-control for preschoolers dreamed up by psychologist Dr. Walter Mischel. While the rules of his experiment are easy, the results are far more complex than he ever could have imagined. In fact, what they tell you about your child at age 4 could have repercussions for the rest of their lives.
Mischel first administered this experiment, dubbed the "marshmallow test," to preschoolers in the early 1960s. They were brought into a barren room, empty of any distractions except a table upon which sat a very tempting treat: the marshmallows. The children were given the choice of eating one marshmallow whenever they wanted or, if they could hold out until the adult instructing them returned to the room, they were rewarded with the two marshmallows.
"We were interested in creating an intense conflict for the child," said Mischel. The children were left alone in the room for 15 minutes -- an eternity to wrestle with the choice between instant marshmallow gratification and delayed marshmallow reward. "That conflict was crucial, because without it, you don't have a situation for testing self-control."
Mischel devised the marshmallow test through a combination of his own expertise in psychology and consulting with an important advisory board: his three young daughters. "I was watching this miracle that occurs when our kids ... really begin spontaneously to show dramatic changes in their ability to control their impulses," said Mischel, adding, "I realized that I didn't have a clue about what was going on in my children's heads that allowed these changes to occur and that's what I wanted to understand."
During the experiment, Mischel noticed that the children who were able to wait for two marshmallows displayed creative ways to distract themselves from temptation. "I'm going to push this stuff as far away from myself as I can. I'm going to distance myself. I'm going to turn around in my chair and look the other way so that I don't see the stuff. I'm going to distract myself strategically. I'm going to sing little songs," explained Mischel.
He learned that the techniques that children showed to delay gratification would have a profound effect on them for decades. Mischel has continued to study his original test subjects for the past 50 years and what he discovered is shocking. On the whole, the preschoolers who were able to wait for two marshmallows, over the course of their lives, have a lower BMI, lower rates of addiction, a lower divorce rate and higher SAT scores. He writes about his findings in the newly published, "The Marshmallow Test: Mastering Self-Control."
Children who displayed self-control were already wired to conquer stress in pursuit of goals and "more able to sustain effort and deal with frustration," said Mischel. That has played out in myriad ways over the last 50 years.
Does that mean children who can't wait for two marshmallows are destined to live less fulfilling lives? Not necessarily. "I have no doubt that self-control skills ... are imminently teachable," said Mischel. It all comes down to training your mind to cool its emotional need for something it's trying to avoid.
In the case of young children, Mischel said the preschoolers who waited for the marshmallows showed strategies that any parent could teach their child. Beyond that, he said, techniques for self-control can be learned at any age.
"(For adults) you can turn something that's very appealing into something that's very aversive," said Mischel. He used the example of how to quit smoking because as a young man, his insatiable appetite for nicotine led to a three-pack-a-day habit augmented with a pipe and even an occasional cigar.
"If you're a smoker and as you approach the cigarette you're thinking lung cancer ... and imagining it very vividly, your picture of your lung with a black spot and your physician telling you 'I'm so sorry to have to tell you etc.' that visualization can be very powerful," said Mischel.
While his techniques for measuring and mastering self-control may be relatively new, Mischel is quick to point out that a focus on self-control is not. "I'm not the first person to think willpower is very important. It's been with us from the story of Adam and Eve and the loss of paradise." If only the Garden of Eden had the marshmallow test, the world might be a very different place.