Backchannels evolve through time, and they are differentiated by culture. They frame our words. But while these backchannels come to us almost as easily as breathing and are as much a product of thousands of years of history as art and music and religion, they're foreign to computers. Scientists could program the whole of the Oxford English Dictionary and countless combinations of “heuristics” — or problem solving formulas — for proper grammar and machines would still have trouble learning this natural language. The notion that virtual humans might have unscripted conversations with humans and one another may seem like science fiction. Real humans themselves often struggle to communicate with one another; whether we're participating in complex international negotiations or wooing a mate we weave a quilt of words and body language meant to express our needs and desires. Computers communicate in strings of ones and zeros, a vocabulary of closed and open circuits determining how they “decide” to run programs. They have no other culture, no thousands of years of history to determine their identity.