WE FINALLY HAVE an answer to the nature/nurture debate, and it appears to be yes.
It took billions of years of biological evolution for bacteria to morph into humanity, but the human ability to learn and to teach each other new tricks means that useful behaviors and ideas don't have to take biological time to spread through the species. Their emergence, the ways we spread them, and the ways they change over time amount to a kind of cultural evolution.
A cultural discovery--our pre-human predecessors' capture of fire--externalized the digestive system that evolution had shaped for our variety of ape. That freed biological energy to grow a big brain. In Blueprint: The Evolutionary Origins of A Good Society, Nicholas Christakis argues that this coevolution has equipped us with a "social suite" of traits that arose through genetic evolution and that have been amplified by cultural evolution, which has in turn influenced our genetic evolution toward propensities that support the social suite. These include the "capacity to have and recognize individual identity," "love for partners and offspring," friendship, social networks, cooperation, "preference for one's own group ('in-group bias')," "mild hierarchy (that is, relative egalitarianism)," and "social learning and teaching."
Christakis, a physician and a sociologist at Yale, buttresses his arguments with evidence from social science, evolutionary biology, genetics, neuroscience, and network science. He presents evidence from beyond the laboratory, drawing examples from the history of shipwrecks and communes and from studies of elephants, bonobos, and dolphins. He even addresses philosophical objections to his claim that our genetic and cultural history prepared humans "to make a particular kind of society--one full of love, friendship, cooperation, and learning."
(If you're familiar with the "Halloween incident" at Yale, you might be surprised at Christakis' optimism: After his wife, at the time also a member of the Yale faculty, wrote an email to students pushing back against warnings about "culturally unaware and insensitive" costumes, both spouses were confronted and shouted at by students. He eventually stepped down from his role as head of a residential college but retained his tenured professorship, while she stopped teaching at the university altogether.)
Christakis embraces a "glass is half full" interpretation of human sociality, but he doesn't shy away from the inseparable shadow...