Jon Hamilton

A large new government study should reassure parents who are afraid that kids are getting autism because they receive too many vaccines too early in life.

The study, by researchers at the Center for Disease Control and Prevention, found no connection between the number of vaccines a child received and his or her risk of autism spectrum disorder. It also found that even though kids are getting more vaccines these days, those vaccines contain many fewer of the substances that provoke an immune response.

Loneliness hurts, but social isolation can kill you. That's the conclusion of a study of more than 6,500 people in the U.K.

The study, by a team at University College London, comes after decades of research showing that both loneliness and infrequent contact with friends and family can, independently, shorten a person's life. The scientists expected to find that the combination of these two risk factors would be especially dangerous.

As far back as he can remember, George McCann lived in fear. When he was asleep he would have horrific nightmares filled with violent images. When he was awake, he often felt threatened by people, including members of his own family. And when he felt threatened, he would become aggressive, even violent.

George spent his childhood certain that something very bad was going to happen. And when he was 12, it did. His unrelenting fears led to a violent outburst at school. And George landed in a psychiatric hospital.

Alzheimer's disease doesn't just steal memories. It takes lives.

The disease is now the sixth leading cause of death in the U.S., and figures released Tuesday by the Alzheimer's Association show that deaths from the disease increased by 68 percent between 2000 and 2010.

Scientists are beginning to understand how people tune in to a single voice in a crowded, noisy room.

This ability, known as the "cocktail party effect," appears to rely on areas of the brain that have completely filtered out unwanted sounds, researchers report in the journal Neuron. So when a person decides to focus on a particular speaker, other speakers "have no representation in those [brain] areas," says Elana Zion Golumbic of Columbia University.