As we traveled the world investigating what makes us human, we always were sure to ask our interviewees just what they think the human spark is. While there was plenty of overlap, there were also a lot of different ideas put forward. And people tended to approach the question differently depending on what their own fields of expertise were.

Alan Alda recently chatted with Steven Pinker in his office in the Psychology Department at Harvard University. Much of Pinker’s research has focused on language – and not surprisingly language is central to his conception of what makes us human.

Watch this video clip to learn more about three big things Pinker thinks set us apart from other animals.