Instead of letting infants cry, American parents should keep their babies close, console them when they cry, and bring them to bed with them, where they'll feel safe, according to Michael Commons and Patrice Miller, researchers at the Medical School's Department of Psychiatry.

The pair examined child-rearing practices here and in other cultures and say the widespread American practice of putting babies in separate beds - even separate rooms - and not responding to their cries may lead to more incidents of post-traumatic stress and panic disorders among American adults.

The early stress due to separation causes changes in infant brains that makes future adults more susceptible to stress in their lives, say Commons and Miller.

"Parents should recognize that having their babies cry unnecessarily harms the baby permanently," Commons said. "It changes the nervous system so they're sensitive to future trauma."

Their work is unique because it takes a cross-disciplinary approach, examining brain function, emotional learning in infants, and cultural differences, according to Charles R. Figley, director of the Traumatology Institute at Florida State University and editor of The Journal of Traumatology.

"It is very unusual but extremely important to find this kind of interdisciplinary and multidisciplinary research report," Figley said. "It accounts for cross-cultural differences in children's emotional response and their ability to cope with stress, including traumatic stress."

The pair say that American child-rearing practices are influenced by fears that children will grow up dependent. But parents are on the wrong track. Physical contact and reassurance will make children more secure when they finally head out on their own and make them better able to form their own adult relationships.

"We've stressed independence so much that it's having some very negative side effects," Miller said.

The two gained the spotlight in February when they presented their ideas at the American Association for the Advancement of Science's annual meeting in Philadelphia.

In a paper presented at the meeting, Commons and Miller contrasted American child-rearing practices with those of other cultures, particularly the Gusii tribe of Kenya. Gusii mothers sleep with their babies and respond rapidly when the baby cries.

"Gusii mothers watching videotapes of U.S. mothers were upset by how long it took these mothers to respond to infant crying," Commons and Miller said in their paper on the subject.

The way we are brought up colors our entire society, Commons and Miller say. Americans in general don't like to be touched and pride themselves on independence to the point of isolation, even when undergoing a difficult or stressful time.

Despite the conventional wisdom that babies should learn to be alone, Miller said she believes many parents "cheat," keeping the baby in the room with them, at least initially. In addition, once the child can crawl around, she believes many find their way into their parents' room on their own.

American parents shouldn't worry about this behavior or be afraid to baby their babies, Commons and Miller said. Parents should feel free to sleep with their infant children, to keep their toddlers nearby, perhaps on a mattress in the same room, and to comfort a baby when it cries.

"There are ways to grow up and be independent without putting babies through this trauma," Commons said. "My advice is to keep the kids secure so they can grow up and take some risks."

Besides fears of dependence, other factors have helped form our childrearing practices, including fears that children would interfere with sex if they shared their parents' room and doctors' concerns that a baby would be injured by a parent rolling on it if it shared their bed, the pair said. The nation's growing wealth has helped the trend toward separation by giving families the means to buy larger homes with separate rooms for children.

The result, Commons and Miller said, is a nation that doesn't like caring for its own children, a violent nation marked by loose, nonphysical relationships.

"I think there's a real resistance in this culture to caring for children," Commons said. "Punishment and abandonment has never been a good way to get warm, caring, independent people."