(CBS News) Does the saying "A friend in need is a friend indeed" mean that a person who stands by you when you need them is a true friend? Or, does it mean that someone who needs your help is eager to prove their friendship? Either way, the latest science proves friends are very good to have, as Rita Braver reports now in our Cover Story:
If you have any doubts about the value of friendship, meet "The Girls," as they call themselves.
"It stands for 'Gee, I Really Love Shopping," laughs Barb.
These seven friends, pouring over scrapbooks of treasured memories, all grew up and still live around Dale, Wis. They've been hanging out three or four times a month for more than a dozen years.
"We all accept each other for who we are," said Molly. "We just get along. You don't find that often that this many people, you know can get along so well."
There's Molly Tews, Barb Nieland, Mary Fieser, Jane Thiel, Chris Schuelke, Dori Krueger and Kathy Peters.
What do they talk about? "Oh, lots," said Kathy. "They're a good venting group when you need to vent about work or your husband, or your children who are adults but, . . . and we love to talk about our grandkids, too."
"Do you feel safe telling these people your deepest personal secrets and know that it's not going to be all over town?" asked Braver.
"Oh absolutely," said Barb. "Sometimes when you complain to them, they're going to go, 'Really, you're complaining about that?'"
Friends can help you shoulder burdens, literally. At the University of Virginia, psychology professor Dennis Proffitt and a team of graduate students demonstrated how they've been asking students -- either alone, or with a friend standing by -- to put on a heavy backpack and estimate the steepness of a hill: on paper, by looking at a pie chart, and by using a tilting device. The overall results are unequivocal:
"They find the hill to be steeper if they're alone, and less steep when they're with friends," said Proffitt. "Moreover, if you look at the strength of their friendship, the more time they spend together with their friend, the shallower the hill appears."
"You're made stronger by having a friend with you?" asked Braver.
"Or, 'I'm less strong if I'm alone,'" he said.
In fact, many studies have shown that people with a circle of friends tend to be healthier and live longer.
But scientists still don't understand exactly why.
"One of the big questions that we're interested in, in our lab, is how the brain takes social relationships and translates that into better health outcomes," said James Coan, associate professor of clinical psychology at the University of Virginia.
He put Braver through the same test he's been doing on a series of subjects, telling her that while getting an MRI she would be given a series of mild electric shocks, but would not know when.
"It's what we call anticipatory anxiety," said Coan, "and that is our interest, because that's the kind of anxiety we're interested in generalizing to our everyday lives. For most of us, the stuff that we worry about is uncertain."
Braver went through one series of shocks alone, and another holding the hand of a good friend, "Sunday Morning" producer Kay Lim. And like all of the other subjects, the parts of my brain that sense danger were less -- much less -- active when she was holding her friend's hand. "I would say it was a bigger difference even than we had predicted," said Coan, examining Braver's scans.
So what does the test tell about what it means to have a friend?