Here's a weird one. Apparently there's a rare genetic disorder called Williams syndrome. Those with this syndrome have characteristic facial and physical features, certain cardiovascular problems and mild to moderate mental retardation.
They are also markedly social, and have greater language capabilities than you would expect from their general cognitive ability. They score significantly higher on tests measuring behavior in social situations, including their ability to remember names and faces, eagerness to please others, empathy with others' emotions and tendency to approach strangers. A little girl with the syndrome who was unusually shy for a Williams child has revealed why. She was found to have retained at least one more gene from the set of genes usually missing in those with Williams syndrome.

I find this interesting for two reasons. One, of course, is the finding of a gene that has such a strong effect on sociability. The other, probably more interesting (since it has more useful implications), is the connection between these "sociable" traits, and language skills, and memory for names and faces.