So here we are in our first class of user interface design, and perhaps the first thing we should ask ourselves is: what is a user interface anyway? We get all our information from screens nowadays, whether it's a desktop or a laptop or a tablet or a phone. We're constantly looking at screens and learning how to do things and how to interact with the world through the screen. And there are certain conventions to the interface of the screen that we're used to, whether those are buttons or menus. We understand how we access the information through a screen through the interface. And these conventions are things that we become used to. But within those conventions, there are levels of flexibility that can shape the experience the user has with the content. We know we always have to scroll down to get content on a website or swipe from side to side on a phone, but what is the actual user interface itself and how does it work? The key components are the user and the interface. The user is the viewer or the person interacting with the content and the interface is the way that the user gets to that content. How they access that content. So in a lot of ways, you could think about the interface as being a bridge between the user and the content. But that bridge is not totally passive. That bridge can shape the way the user experiences the content. And there are lots of models in the real world for how interfaces work. If you think about a book for instance, that's an interface in itself. It's an interface between the reader and the story. The book is just type on paper, but what the reader receives or experiences is the novel or the story itself. You could look at something like road signs, where the driver is the user and what's being conveyed are the rules of the road through a graphic medium of a road sign. Nowadays, everyone receives pretty much everything through a screen, and that screen can act as a mediating device. And what that means is, the screen can change the experience. If you think about something like a news event for instance, that news event could be perceived in different ways depending on how the story is told, upon how the story is mediated. So if the basic story is that self-driving cars have been approved, on the one hand you might think that that's good news, but depending on how it's reported, how it's mediated, you might think that that's bad news. Marshall McLuhan famously said that the medium is the message. But with interface design, I think it's more of a case of the medium affects the message. The medium can shape the message. And that medium is the interface. So the interface shapes the experience. So if everything everyone experiences is through the screen, through the interface, then the interface designer has a lot of power. Because the interface designer is shaping every experience that everyone has. And this gets at the heart of what we're going to look at next: the interface shapes the experience. And the interface is the UI part, the user interface design. And the experience is the UX part, the user experience design. And you put those two together and you've pretty much got control over how everybody experiences every kind of content.