A turkey vulture makes quick work of a dead rabbit at Martin Luther King Jr. Regional Shoreline park in Oakland, Calif. Sebastian Kennerknecht/Minden/Corbis hide caption

itoggle caption Sebastian Kennerknecht/Minden/Corbis

"What I'm saying is that culturally we need a much better balance. We need more of a yin and yang between [introverts and extroverts]." - Susan Cain James Duncan Davidson/TED hide caption

itoggle caption James Duncan Davidson/TED

Environmentalist John Francis speaks about the 17 years of his life during which he never spoke a word. Andrew Heavens/Courtesy of TED hide caption

itoggle caption Andrew Heavens/Courtesy of TED

"I began to learn at least what other people felt and what they wanted to say before cutting them off with my own diatribe. I used to do that." - John Francis Andrew Heavens/TED hide caption

itoggle caption Andrew Heavens/TED

In sighted people, the part of the brain that recognizes faces is linked to the brain's visual system. But in blind people it seems wired to circuits that process sound. Tina Zellmer/Ikon Images/Corbis hide caption

itoggle caption Tina Zellmer/Ikon Images/Corbis