Before kids have friends or love interests, they have siblings. Brothers and sisters come earlier in life, and stay later. “Our brothers and sisters,” family sociologist Katherine Conger of the University of California, Davis told Time, “are with us for the whole journey.”
But that journey can be a complicated one, Conger’s research shows.
When designing a longitudinal study she started in 1989, she decided to add questions about siblings, to study the dynamics between them and their parents over time.
In one study, she and her co-authors sought to find out whether mom and dad treated kids differently based on their birth order. She wanted to know whether the kids perceived their treatment to be fair, and how it affected their self-esteem.
Mom and dad definitively have favorites, her research, published in the Journal of Family Psychology, showed: 70% of dads and 74% of moms reported preferential treatment toward one child.
But while that differential treatment didn’t seem to affect first-borns’ self-esteem all that much, it did take a toll on younger kids’ sense of self-worth (perhaps because it was the first borns who felt preferred).
“I was a little surprised by that,” she told Quartz. “Our working hypothesis was that older, earlier born children would be more affected by perceptions of differential treatment due to their status as older child—more power due to age and size, more time with parents— in the family,” she said.
She also found that everyone thinks they’re treated unfairly.
“Everyone feels their brother or sister is getting a better deal,” Conger said. “Regardless of how you look at it, both [earlier and later-born kids] are perceiving preferential treatment.”
Conger studied 384 adolescent sibling pairs (called dyads) and their parents across three years. To be in the study, kids had to be living with two biological parents, and each 7th grader had to have a sibling within four years of age (older or younger).
The data were collected once a year with two visits to a family’s home. In the visits, families answered certain questions about their relationships with each other, with friends, and described what kinds of activities the family liked to do.
In the second visit, the interviewer asked the family to solve three family conflicts, based on a short survey of each family member and the first visit. The sessions were videotaped. Behaviors were then rated by trained observers.
Perhaps the discovery that no matter what parents do, kids will think they are treated unfairly can be a liberating one. Next time you find yourself meticulously measuring ice cream scoops, or managing when to buy new clothes for one kid versus another, or paving the way for the “difficult” conversation with Jack about why Beatrix is going to see the dinosaurs without him, don’t. It won’t make a bit of difference.