Social isolation can have a huge impact on health. It can be as detrimental as being obese, and only slightly less harmful than smoking. The feelings of loneliness are something all humans can experience, regardless of culture. And even social animals will die at younger ages when they are isolated from the group.

AAAS member John Cacioppo is the Director of the Center for Cognitive and Social Neuroscience at the University of Chicago. He has spent his career researching loneliness and depression in the field of social neuroscience. Social neuroscience is a growing interdisciplinary field. It looks at how the brain influences social behavior, and in turn, how social environments influence the brain.

Cacioppo and his colleagues complied a book about loneliness and how it affects your health, titled "Loneliness: Human Nature and the Need for Social Connection." In a reading from a section of his book, Cacioppo talks about how animals also share the need for, and benefits from, social connections. He talks about how the fear of loneliness contributed to Charles Darwin's theory of evolution. And, it introduces how important loneliness is to health as well as why it deserves more attention and study.

• Loneliness: Human Nature and the Need for Social Connection, by John Cacioppo and William Patrick