Nobody questions that the color of our eyes is encoded in our genes. When it comes to behavior the concept of "DNA as fate" quickly breaks down -- it's been long accepted that both genes and the environment shape human behavior. But just how much sway the environment holds over our genetic destiny has been difficult to untangle.

Scientists at the Salk Institute for Biological Studies have found a clever way to sort one from the other: They compared the social behavior of children with Williams syndrome -- known for their innate drive to interact with people -- across cultures with differing social mores. Their study, published in a forthcoming issue of Developmental Science, demonstrates the extent of culture's stamp on social behavior.