Want to learn more about your children? Then get out the marshmallows.

Here’s how it works: Tell them they can have one marshmallow now — or wait and have two in 15 minutes. According to the famous study first done by psychology professor Walter Mischel 40 years ago, children’s ability to wait (or not) says a lot about how well they’ll do in school, with friends, and with family. And, incredibly, waiting for that extra marshmallow can even predict their future success as adults — in work and relationships.

If your kids are the “I want the marshmallow now!” type, don’t worry. The news is still good: Learning to control emotions and behavior is a skill that can be taught. In fact, a recent study published by the Journal of Abnormal Child Psychology found that teaching self-control techniques to elementary school-age children who had difficulty reining in their emotions and behavior significantly reduced suspensions and other disciplinary problems.

That said, knowing how to think before acting can be especially difficult for very young children. But by helping them practice over and over (and over), parents are providing one of life’s most valuable skills.

Lay out expectations

Some kids react badly because they don’t know what to expect in some situations or what will be expected of them. So fill them in ahead of time if they need to wait for something or be asked to do a difficult task: “We’re going to visit Grandma, and she and I will be talking for a while. Let’s put together a bag of crayons and paper so you won’t be bored.” “My friend and her children are coming to visit. You might need to share some toys, so let’s put away the ones that are really special to you.”

Give them the words

Help children learn to recognize the troubling emotions they’re feeling before having an outburst or tantrum: “Boy, you were really mad when I said you couldn’t have a quarter for the gumball machine.” “You seemed sad when your sister said you’re too little to play with her and her friends.” Also, encourage children to give voice to what they are feeling: “I feel sad when …” or “I feel frustrated when … ” You can also help them learn to use self-control phrases (which, in turn, can help them refrain from impulsive, thoughtless behavior) like “May I borrow that?” “It’s OK, I can share with you,” “I’ll wait my turn,” and “I would like it now, but I’ll wait until later.”

Take a break

Create a quiet place at home where an out-of-control child can calm down. It can be a pillow-filled corner in the living room or a cozy spot in a child’s bedroom. By providing an at-home refuge, parents can teach kids that there’s a way, and a place, to collect themselves when things get out of hand.

Provide a reward

Young kids often do better at a task if they get a reward at the end. It doesn’t have to be a material reward (offering toys and treats can set a bad precedent), but a natural consequence for showing self-discipline. The reward might be picking out favorite stories after getting ready for bed when you ask, or getting to choose the dessert after helping to set the kitchen table.

Praise your children

When you see kids practicing self-control, let them know. This kind of positive reinforcement will help them think of themselves as people who can successfully control their behavior: “I love how you waited patiently for your turn.” “This is the third time this week you didn’t interrupt me when I was on the phone. I really appreciate that you waited to talk with me.”

Play at self-control

For young children, the best way to learn something is through play. So on the way to the bath, in the supermarket, or on the drive to school, have your children stop and start different actions, like freezing when you say “Potato!” In the car, every time there’s, say, a yellow sign, have your kids clap and say, “Yellow sign!” These types of games teach kids to stop and think before acting, a self-control essential.