ST. LOUIS — If your child forgets his lunch or struggles with school work, a little more loving might turn things around.
Supportive mothers who practice positive reinforcement seem to help their kids' brains grow, according to new research from Washington University.
Brain scans show that the hippocampus — the region of the brain that plays a role in memory, learning and stress response — is 10 percent larger in the children of nurturing mothers compared to the brains of children whose mothers were deemed less supportive.
The take-home message for working and stay-at-home parents is to praise children more than you scold them, the researchers said.
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"Parents might feel guilty because they're working, and we work a lot as well," said Dr. Kelly Botteron, a professor of child psychiatry and co-author of the study. "But when you're home in the evening and you're trying to rush through homework and trying to get dinner ready, if you remember to say a couple nice, really positive things ... I think a lot of parents could do that and it's a practical thing that has very little risk to it."
It's long been known that orphans and other neglected children who are placed in loving homes can improve their behavior and health. And while a link between nurturing mothers and their offspring's brain growth has been established in rats, the study is the first to show the same anatomical process in humans.
As part of their ongoing research on childhood depression, staff members watched how two groups of 92 children ages 3 to 5 interacted with their caregivers (usually mothers) during a stressful task. One group of children had symptoms of depression and the others were assigned to a control group.
For the task, the mothers were told to fill out a questionnaire. The child was given a wrapped present but told not to open it right away. The eight-minute "waiting task," as it's known, has been used previously by researchers as a reliable indicator of parental nurturing skills. The task is thought to simulate situations at home, such as a parent distracted by cooking dinner while the child needs to focus on homework.
Researchers who reviewed the taped interactions rated the mothers' responses to their children's behavior. Mothers received points each time they praised the child's patience or offered encouragement to not open the gift.
The researchers acknowledged they're not getting a complete picture of family life, especially if Mom was having a bad day. But they are confident the results of the MRI brain scans on the kids, performed four years after the "waiting task," indicate that children who have more supportive mothers also have bigger brains.
Children with less supportive mothers had a hippocampus volume that was 9.2 percent smaller than the children of more nurturing mothers. In children with depression, the effects of nurturing were not as positive, and the researchers think the disease process has a greater effect on their brain development.
The researchers plan to run second and third MRI brain scans on the children, who are now pre-teens, to watch brain development over time.
Although the study wasn't designed to look at fathers, foster parents or grandparents, the researchers said the positive effects of nurturing can come from any caregivers, which can be reasonably stretched to include teachers.
"If you know your child is in a difficult situation, to reinforce to them that you know it's a hard situation but they're doing such a great job, that's the kind of parenting we would try to encourage," Botteron said.
The researchers were careful to point out they're not opposed to disciplining children or giving them boundaries.
"You should be supportive and nurturing, which is not the same as spoiling and not the same as smothering," said the study's lead author Dr. Joan Luby, a professor of child psychiatry.
One mother said it was exciting to hear that something she already believes in could have an effect on her children's intellectual, and not just emotional, development.
"For a nurturing parent it's both beautiful and frightening because many of us who spend a lot of nights wondering whether we're doing everything we possibly can for our children, this falls into the category of one more thing to worry about," said Danielle Smith of O'Fallon, Mo., who has two young children and writes the blog Extraordinarymommy.com. "It sounds like a bonus to me, but I have to embrace the idea that what I'm doing is enough.