Scientists have been talking about Darwin's finches and orchids and barnacles for a solid 150 years now, but the focus this year was on Darwin's humans. Specifically, why humans are emotional, social and even moral beings. Here's Darwin on the origins of human communities, in The Descent of Man:
It has often been assumed that animals were in the first place rendered social, and that they feel as a consequence uncomfortable when separated from each other, and comfortable whilst together; but it is a more probable view that these sensations were first developed, in order that those animals which would profit by living in society, should be induced to live together. ...For with those animals which were benefited by living in close association, the individuals which took the greatest pleasure in society would best escape various dangers; whilst those that cared least for their comrades and lived solitary would perish in greater numbers.
At the conference, there were presentations on "The Evolution of Emotion and Emotional Expressions in Humans and Other Primates," "The Evolution of Human Social Cognition," "The Origins of Complex Societies in Primates and Humans," and many others along this line. As Barbara King of the College of William and Mary pointed out, people study great apes and other primates to get clues about how our shared ancestors behaved to each other, and even what emotions they felt. "We wouldn't be humans if ancient apes hadn't been deeply emotional and social," she says.
All evolutionary theorizing aside, the best part about attending these types of talks is that you get to see fun film clips of chimps or gorillas or orangutans playing or fighting with one another—basically, apes going ape. This one is from King's work at the National Zoo. Here's how she describes it:
When a conflict breaks out between a silverback and a blackback male, the family members (not biological but social family members) literally line up in support of the younger male. The juvenile male...even tries to intervene, only to be swatted away effortlessly. We see emotion here: not just on the screaming nervous face of the blackback (I should add, the defecating and screaming blackback) , who shows his fear even as he refuses to do what the silverback wants him to do—but also in the ways that the social bonds become visible to us in the apes' actions.