Charles Darwin was deeply interested in the origin and evolution of emotion--he saw it manifest not just in humans, but in other mammals, even insects. Psychological researcher Paul Ekman says that Darwin saw his exploration into emotions as an "important contribution showing the commonality of all people and a common descent."

In an episode of Science Podcast, host Robert Frederick talks with Ekman and other scholars of human and animal emotion who spoke at a symposium during the AAAS Annual Meeting.

A central line of thinking: By studying the complex emotions of apes--their happiness, fear, and even grief--we can see how emotions served as a crucial platform for human evolution. But here's an interesting thing that set humans apart: We can regulate our emotions, and our brain circuitry, by writing about our feelings.

Listen to the full report on Science Podcast.