Playing with a pal is not just board games, backyard soccer, slime, bikes, and lemonade stands. It’s actually shoring up your child’s mental health, banking trust and security that she can draw on for years to come.

Kids don’t need a big group of friends to see these benefits. In fact, quality matters more—a lot more—than quantity. Whether it’s with one, two, or three people, it is the “experience of having a really close, trusting, supportive relationship that goes really far,” says Rachel Narr, a Ph.D. candidate in clinical psychology at the university and the lead author of the study.

What It Means to Be a Friend, Age by Age

Friendships grow and change a lot in childhood—just as kids do. Roughly, here’s what you can expect as relationships become more complex.

• Six- and seven-year-olds make and relate to their friends based on who’s nearby and who’s similar to them—say, a neighborhood kid who is close in age, or a classmate who likes the same playground games. It’s all about location!
• Seven- to nine-year-olds are becoming choosier about playmates. They are likely to friend those who share common interests. And as they mature, kids are learning to see things from another person’s perspective, and to act accordingly.
• Nine- to twelve-year-olds start to take the next step, building relationships based on trust. They are recognizing what it means to be part of a group, and that friendship means giving as well as, or more than, taking.

The BFF Bonus

Aside from the strengthened self-worth and sunnier outlook that Narr found, kids have more to gain from friendship. Through their relationships with their pals, they learn and practice the social skills they’ll need for life—how to make conversation, to negotiate and collaborate, to read and react to others’ emotions. Friends help each other figure out appropriate behavior, and they can protect each other from bullying. Hanging out with friends makes kids feel good, reducing stress they might be feeling from school or family issues.

If your child is having a hard time with friendship, step in. Help him set up playdates. During those get-togethers, offer support by suggesting some activities the kids can do, or just by being nearby in case they need some guidance on getting along. Often it helps to start small, with short get-togethers of an hour or so. Experiment with neutral locations, like the playground. And recognize that your child might need coaching on strategies like how to introduce himself to new people or cope with disagreements.

Other options: Try extracurricular activities, including sports like soccer and gymnastics, or classes for music, theater, and art, to expand your child’s social circle. And check with her teacher or her school’s guidance counselor to ask for suggestions. They have been around this block!