We spend roughly 60 per cent of our communication time listening, but we're not very good at it. We retain just 25 per cent of what we hear. Now not you, not this talk, but that is generally true. Let's define listening as making meaning from sound. It's a mental process, and it's a process of extraction. We use some pretty cool techniques to do this. One of them is pattern recognition. (Crowd noise) So in a cocktail party like this, if I say, 'David, Sara, pay attention,' some of you just sat up. We recognize patterns to distinguish noise from signal, and especially our name. Differencing is another technique we use. If I left this pink noise on for more than a couple of minutes, you would literally cease to hear it. We listen to differences, we discount sounds that remain the same. And then there is a whole range of filters. These filters take us from all sound down to what we pay attention to. Most people are entirely unconscious of these filters. But they actually create our reality in a way, because they tell us what we're paying attention to right now. Give you one example of that: intention is very important in sound, in listening. When I married my wife, I promised her that I would listen to her every day as if for the first time. Now that's something I fall short of on a daily basis.