Willpower, resolve, determination: Successful people become successful by working hard and sticking to their long-term goals.

So it's no surprise the "Marshmallow Test," one of the most famous research studies -- and a favorite of motivational speakers -- indicated a link between success and delaying gratification

If you aren't familiar, the Marshmallow Test is simple: Put a marshmallow in front of a kid and tell them they get a second one if they wait 15 minutes. If they eat the first one before 15 minutes is up, they don't get a second marshmallow; if they wait, they do.

Simple, easy to understand, easy to apply: Researchers said the test indicated the likelihood of a child's future success. Higher SAT scores. Better social skills. Less likelihood of obesity and substance abuse. Delaying gratification -- holding out while the researcher left the room and not eating the first marshmallow -- was the reason those kids turned out to be more successful. 

Or not. Correlation doesn't always mean causation.

The original study followed approximately 90 kids who were all enrolled in a preschool on the Stanford campus (conveniently for the Stanford researcher.) A new, larger study -- involving kids from a much broader range of races, ethnicities, parent backgrounds, etc. -- reveals that kids who wait to get two marshmallows instead of giving in and eating the first one tend to come from wealthier households.

In short, kids with affluent parents are more likely to delay gratification. 

Why? Maybe those kids are more willing to wait because they haven't been conditioned by experiencing relatively scarce resources. Give me something I almost never get... and I might not be willing to wait to get another one -- I might decide I need to grab what I can now.

Or maybe those kids are more willing to wait because they've learned to believe that a bird in the hand is always better than two in the bush. If I hope to get something later, but financial hardship makes later never come... now naturally becomes much more attractive.

Or maybe it's easy for those kids me to wait for the second marshmallow because they like chocolate chip cookies even more... and they know that when they get home, there are usually plenty of cookies in the pantry. 

All of which means the ability of a child to delay gratification may not be a driver of future success, but the result of his or her family and financial circumstances.

As Captain Obvious might say, environment and experience play a huge role in shaping the people we become.

What to Do If You're Not "Rich"

Even so, the ability to delay gratification -- to resist temptation, to take the long view, to choose between a smaller, more immediate financial return and a larger return at a later date, to embrace the idea that work always proceeds reward -- is a crucial factor for long-term success. 

As no less an authority than Steve Jobs once said, "I'm convinced that about half of what separates successful entrepreneurs from the non-successful ones is pure perseverance."

Which is why, as a parent, one thing you can try to do is only make promises you know you can keep, or at the very least, to be willing to do everything you possibly can to keep. 

And if, in spite of your best efforts, you can't keep a promise, to explain why you weren't able. By explaining why you couldn't, your kids will begin to gain perspective.

And begin to understand that no matter how hard they try, occasionally things outside of their control will cause them to fail.

And that failures are, while regrettable, also necessary steps on the road to success. Every successful person has failed, Numerous times. Many more often than most; that's why they're successful now.

Explaining why you failed, and owning that failure, will help your kids learn to not just embrace failure but learn from it... and work hard to make sure that next time things will turn out differently.

That's one of the best ways to help them learn to delay gratification, because they'll see, firsthand, how hard work and perseverance help you eventually succeed... and how hard work and perseverance can take them wherever they wish to go.

Regardless of where they may start.

Because now may be good... but later is almost always better. 

Especially if you're willing to bet on yourself.

And do the work.