From Edge:

Kandel150 In keeping with the theme of this year’s Question: “What Are You Optimistic About”, Edge asked neuroscientist and Nobel Laureate Eric Kandel for a sampling of recent developments in neuroscience that inspire his optimism. “in a field as broad and as deep as neuroscience,” he writes, “it is difficult to select simply four contributions. I therefore consider this a sampling of the contributions that drive my optimism rather than a true selection of the top four. Moreover, I have simplified the task by dividing the field into four areas: Molecular Neuroscience, Systems Neuroscience, Cognitive Neuroscience, and Neuroscience of Psychiatric Disease.” 

In a larger sense, social cognition is an extreme example of a broader issue in biology of mind, and that is social interaction in general. Even here we are beginning to make some rather remarkable progress. Cori Bargmann, a geneticist at the Rockefeller University, has studied two variants of a worm called C elegans, that differ in their feeding pattern. One variant is solitary and seeks its food alone; the other is social and forages in groups. The only difference between the two is one amino acid in an otherwise shared receptor protein. If you move the receptor from a social worm to a solitary worm, it makes the solitary worm social.

More here.