It seems to me to make as much sense to talk about literature as a large-scale human phenomenon without bringing in evolution as it does to engage in cosmology while you're thinking the universe is still geocentric.

There is behavioral ecology, which looks closely at the difference different ecologies make to behavior and other features of animals and humans. There's evolutionary individual psychology, there's evolutionary social psychology. In Darwin's terms, evolution couldn't exist without variation, and variation is important in behavioral genetics. And so on, and so on. There are so many instances in which evolution actually sharpens the precision, I think, with which one can find out the importance of differences. We're interested in differences as well as commonalities.

Art and literature need extreme sociality to a degree that even dolphins don't have. We are the only large mammalian species that has such intense sociality. There are some small mammals that have become eusocial - the mole rats - but that's a different thing. Humans are able to understand one another at very high levels, to cooperate in very large groups. Humans depend on one another in ways that are an absolute precondition to sharing the kinds of information that makes narrative possible.

I would be very surprised if on another planet we discovered a species as intelligent as humans that didn't have narrative, or didn't have art in general.

There's a young Danish guy who has done a lot of work from an evolutionary perspective, Mathias Clasen. Basically, his argument is we've evolved to fear the monstrous, to be very wary of large, unknown, life-threatening forces. In art, we can play with these things in ways that allow us to feel the intensity of the horror, but in "safe mode," if you like, detached from real consequences.

I think that's an important part of art in general. Especially in literature, in stories, we play with eventualities that may put us through a lot of intense negative feelings - say, in horror films or tragedies as intense as King Lear - but we come out feeling richer. We've lived to the fullest, we've tested ourselves in these environments.

In fiction the story lives the more everyone comes to life, the more each character seems to exist in his or her own right.