When Morgan Moore invites her closest pals over for a slumber party, the Moore household in Wai'alae Iki inevitably bursts with peals of laughter and girly-girl chatter late into the night.

Morgan and her girlfriends enjoy the standard sleepover diversions: baking cookies, watching their favorite movies, painting each other's nails, and — of course — having pillow fights in their pajamas.

It's all about "giggling and staying up late at night," the 11-year-old said.

Morgan is among tweens (ages 8 to 12) who have discovered the joys of sleepovers. A national survey conducted earlier this year by Impulse Research, a marketing research firm, showed 71 percent of mothers say their kids attend the most sleepovers during the summer months, which lasts until Sept. 21.

While pillow fights and all-night snack fests may be loads of fun for kids, slumber parties may also be good for them developmentally, fostering independence and improving social skills such as intimacy- and trust-building, experts say.

"It can be a very helpful and a very important part of their childhood," said Jeffrey D. Stern, a clinical psychologist who specializes in child and family issues.

Stern likens sleepovers to other "mastery experiences," he said, such as sleeping with the lights out for the first time or learning how to ride a bike — experiences that involve an opportunity for children to overcome fear, trepidation and anxiety, he said.

"It is, for the child, a journey of independence, and for the parents, it's a letting go," Stern said. "So in both ways it's kind of a stepping stone."

Another advantage of a sleepover is it gives children a chance to see how other families live, Stern said, who's also an instructor in child development and research methods at the University of Hawai'i.

Morgan's mother, Robin Moore, agrees.

"I think it's important for kids to experience another family's home life," said Moore, 41, a business owner and stay-at-home mom of four children, ages 13, 11, 9 and 6.

Being exposed to another family's rules, morals and possessions helps give children perspective, both Stern and Moore said.

Mom and Dad also can benefit from slumber parties, Stern said.

"Parents can have impact on the choice of friends that their kids make and how to influence which friends your kids choose ..." he said. "You can be part of the friendship-making ... which will be so influential over them in the years to come."

By getting to know the parents of your child's sleepover buddy, you'll know what kind of parenting your child's friend is getting, if that's compatible with your parenting beliefs, and if "it's a safe friendship to have that will hopefully lead to responsible choice making," Stern said.

But most important of all, sleepovers are a way for kid to be kids.

"The key for kids is they like the company," Stern said. "Kids at this age, peers and friendships start to become more and more important."

Kailua resident Lori Kahikina-Moniz, the mother of three boys, ages 9, 6 and 4, hosts sleepovers for her eldest and allows him to sleep over his friend's house, as well.

"It's like a treat for my older son because being the oldest, he has a lot of responsibility to take care of his two younger brothers, so it's like a reward for him," said Kahikina-Moniz, 34, an engineer.

When Kahikina-Moniz holds slumber parties at her home, her son La'akea can count on a night filled with movies (preferably adventures or comedies) complete with popcorn topped with all the fixings — candy, arare or furikake — board games, card games and video games.

"Sleepovers are cool 'cause I get to go over my friend's house or my friend gets to come over (my house) and spend the night, which happens rarely, so it's just fun," La'akea said.

Reach Zenaida Serrano at zserrano@honoluluadvertiser.com.