Jaren Wilkey, BYU
Laura Padilla-Walker

PROVO — They may steal your baseball cards or stain your favorite shirt, but despite the occasional tiffs, siblings bring big benefits, say BYU researchers.

A new study by BYU Family Life professors Laura Padilla-Walker and James Harper found that positive relationships between preteens or young teens and a sister or brother defended against depression, lowered the risk for delinquency and promoted pro-social behaviors such as kindness and empathy.

"Sibling affection, regardless of gender, was a really positive thing," Padilla-Walker said. "We know that siblings are important in early childhood, but this finding is interesting because it shows that they still matter in adolescence."

Sisters were especially good at guarding against depression, perhaps because they usually talk more than boys and can act like a sounding board, Padilla-Walker said.

The researchers studied nearly 400 families with at least two children where one child was 10 to 14 years old. They asked the target children about their relationship with their nearest-in-age sibling, older or younger, then repeated the questions one year later.

Children who reported that they shared with their sibling, did things together and showed physical affection were more likely to be charitable and less likely to act out or show depressive symptoms, according to the study.

The study also found that a sibling's influence was at least as strong as a parent's in promoting things like kindness or generosity.

Although parents are instrumental in teaching those attitudes to young children, by the time a child reaches 10 or 11, a sibling relationship may continue to drive that pro-social behavior, Padilla-Walker said. It's also due to a "horizontal" or peer-to-peer relationship between siblings where the child acts out of love or friendship, rather than out of obedience in a vertical, authority-based, parent-child relationship.

"We have decades and decades of information aimed at parents saying, 'You influence your children,'" Harper said. "But we don't have decades (of information) aimed at siblings saying, 'You influence your siblings.' In some ways that will relieve parents because they can say, 'It's not all me.' "

Benefits of siblings weren't as pronounced in single-parent families because siblings often took on more of a parent role, rather than that of a sibling.

And just having a brother or sister didn't ensure a benefit. If the sibling relationship was negative and hostile, there was a greater likelihood of delinquent behaviors and depressive thoughts, Padilla-Walker said.

Parents should encourage affection between their children and seek to quash fighting but remember that the real concern is a lack of affection that goes beyond the daily squabbles, she said.

"My kids will fight like cats and dogs, then the next minute they're snuggling and reading a book together," Padilla-Walker said. "I'm not worried about them."

The data was gathered as part of the "Flourishing Families Project," a longitudinal study involving nearly 700 families in Utah and Washington.