Michelle Trudeau

Bears do it, bats do it. So do dogs and humans. They all yawn. It's a common behavior, but why is a bit of a mystery. Researchers think yawning may perk up the brain and help with social bonding.

If your mom had to run through the name of everyone in the family, including the dog, before hitting yours, it's probably because you're all in a mental folder labeled "loved ones."

Angela Stimpson donated a kidney to a complete stranger. Why did she do it? Researchers found that the brains of Stimpson and other altruists are sensitive to fear and distress in a stranger's face.

Too stressed to get seven hours of solid shut-eye tonight? Prepare to be even less resilient tomorrow. Stress disrupts sleep, which feeds depression, anxiety — and more stress, scientists say.

When researchers asked young children to figure out an experiment using cause and effect, they did a much better job than young adults. That may be because their thinking is more flexible and fluid.

Maybe it's true that you never get a second chance to make a first impression. People are judging your personality from the first word you speak, scientists say. Try it yourself with our quiz.

It's easy to think that a shaking hand could be a sign of Parkinson's disease. But it's more likely essential tremor, an ailment that's not life-threatening but can become debilitating.

Most research on memory loss in the elderly focuses on dementia, Alzheimer's disease or other brain diseases.

But neuroscientist Emily Rogalski from Northwestern University's Feinberg School of Medicine knew there is great variation in how good memory is in older people. Most have memory loss to varying degrees, but ...