Hey Don. >> Hi Scott. >> So, you've just been talking to us about swiping your ID card in a door. And this is a class about interaction design. What's the connection between the card in my wallet and the design interactions? >> There are some fundamental principles about designing for interaction. And they apply whether it's a card, whether it's your hand waving in the air, whether you're using a device. And they're very simple. How do I know what action is possible? How do I discover how to do it? And how do I know whether I've succeeded? Very simple. So for the card, I had to, well, realize that I had to do this. And there's no real way of knowing except having someone show me before hand. And then I had to have the right card, and I had to know which position to use. I also had to know when it succeeded because, you know in this building, sometimes this doesn't always work. There are rooms I'm not allowed in. So there's a little green light. That's feedback. Okay, you can come in. So, those same principles apply whether it's a device like this or a gesture device, a screen that I swipe on or whether it's in my new living room or I want the TV to come on, and I [SOUND] clap my hands, or say louder or softer. Same principles, discoverability, feedback. In the end I need a good conceptual model of how things work, and again, I get that through discoverability, feedback. >> So what makes a good gesture? >> Well, ideally, the gestures we use should be what we call intuitive, easy to understand. They're sort of a cultural standard. So, this, for example, culturally, across all the cultures of the world, it means more. It's a higher pile. You put more stuff, it gets higher. So, this means higher, which also means more, which therefore means more sound or more light. So, that means less in the same way. But, other gestures are very arbitrary. Well [LAUGH] I was trying to jump through an arbitrary one, but I'm not. Other gestures are more arbitrary. And sometimes they vary from culture to culture. So you have to be careful in designing them. The best way is if you can give some hints, some general sign that this is a gesture that's required. If you have a picture on the screen it's actually pretty natural to put two fingers on it and spread them apart to make it bigger or squeeze them together to make it smaller or even to rotate it this way. Those are natural, but most gestures, no. The number of total number of natural gestures is going to be 10, 20, yeah that means come here but what else? Does that mean yes? Does that mean no? It's really quite arbitrary. So what does that mean, which is the way they shake in India. They're very arbitrary. >> Here you have an artifact from the Mac culture. We were looking at a gesture earlier that seemed kind of confusing. Can you show it to us? >> This is a good example because it's a wonderful feature, but it's very arbitrary. In fact, I only learned about it today. Despite the fact that I had worked at Apple for ten years. And I've been using Apple computers since the Apple II. So here I have a webpage, happens to be my own. It has the word interaction on it. And if I put the cursor interaction and I take three fingers and I tap, look at that! Up pops a definition that says, interaction, a kind of action that occurs as two or more objects have an effect upon one another, etc. That's wonderful but how would you ever learn that? I had to be told. >> And when should somebody use, you know given that a gesture like this can be hard to discover but is convenient once you're an expert, at least some of the time. How should people decide whether to use a menu or to use a gesture? >> Menus are wonderful because, when you can't remember you just click on the menu, there's a list of possibilities. But you know, on small screens and on these beautifully laid out screens, they take up a lot of what we call screen real estate, a lot of space. And they often interfere with the task you're trying to do. Gestures are more fun. They're delightful. They're very powerful. But there's no sign of what they should do or where they are or how to move them, what to do. So why not have both? You know, in the normal computer, the old-fashioned type, we have a mouse. And usually the right button, you click the right button, up pops a little menu, giving you possibilities. So why not on these screens have a gesture, maybe a long push or something that's standardized? Whenever I do that, up pops a little menu that suggests, here are the gestures you can do, to give you important advice or move to the next screen or whatever. >> And the context menu you talk about that invokes on an action gets around some of the challenges, limited screen real estate, which is one of the appeals of clusters. >> Yes. Absolutely. >> So I was really curious about one thing that you said in your description about gestural interfaces is you used the word fun several times. And in our field historically where we talk about industrial ergonomics or things like that, fun wasn't part of the vocabulary 30 years ago. >> Yeah. No, I wrote this book, Design of Everyday Things, in 1988 and the word fun and emotions were not in there. I just rewrote the book in 2013 and there I have big sections on emotions because emotion is how people are built. We are emotional creatures, and emotion is a wonderful, and gestures have brought back emotions. I just love when I am on a list here. I love the fact that it bounces. You know, what does the bounce do? It gives no information, but it's just kind of fun. And sometime when I'm passing the time, I just bounce or I push how far can I get it over, you know. And yeah, it's fun. It's delightful. It's pleasurable. And it's because of the gestures. >> Well, it's been really fun having you here today, Don. Thanks so much for joining us. >> Thank you, Scott. You're welcome.