Heuristic number six is recognition rather than recall. You want to minimize the user's memory load by making objects, actions, and options visible. The user should not have to remember information from one part of the dialogue to another. And instructions for use of the system should be visible or easily retrievable whenever appropriate. Why is this important? Well, as we've discussed in earlier lectures, a familiar stimulus triggers retrieval from long-term memory. So if the user recognizes something on the screen, it will be easier for them to remember that that's the action that they need, or that's the option that they need to take rather than having to recall it from long-term memory. Because if they have to recall it, it will force them to recreate the chain of associations themselves, rather than having it provided to them. Or it will force them to have to learn through elaborative rehearsal what the commands and operations are that they need to perform. And recall will fail unless the actions, or the information that users need to remember, are frequently used, recently used, or strongly associated with information that they all ready have. So let's look at an example of how recognition, rather than recall, is used in user interfaces that you might be familiar with. Let's say I wanted to make this dot on the screen animated, I wanted to make it move around. I'm going to switch into edit mode. So what I'm going to notice is this text right up here at the top that says, Animations. And so I can recognize that that's where I probably need to go in order to perform this operation. When I click on the Animations tab I'm presented with a whole set of options that I can chose from that will allow me to animate this dot in different ways. And again, I can recognize the option. I can decide, do I want this to fly in from the side? Do I want it to peek in? Do I want it to just appear? Or whatever it is, rather than having to remember or recall the command that would perform the operation that I need. What we just saw is an example of a direct manipulation interface, which is the style of interface that most graphical user interfaces use. A direct manipulation interface provides all of the objects that we might want to manipulate and all of the operations we might want to perform as visible options on the screen so that we can always recognize what it is that we need to do rather than having to recall it. And most interfaces work this way, and you want to make sure that your interfaces do, as well. There are a few places though where recall is still a part of a typical user experience. One of this is interfaces that require us remember textual commands that we type into a system. The most common places that this is seen is in command-line interfaces such as this one shown here. Where the user needs to remember command syntax like cd for changing directory. Ls with these options for listing the contents of a directory. And all this junk down here for listing the running programs and searching through the list and so on and so forth. And an interface like this just requires the user to recall and memorize all of these commands and the options for these commands and so on and so forth. Another place that recall comes up in typical user interaction is with passwords. And this is for very good reason, we don't want to display users' passwords on the screen. However, it's worth keeping in mind that this is a place where users are going to have to memorize something. And as designers, we can make that easier or harder through how we present passwords and what rules we put around the passwords that people are allowed to use. Finally, an area of user interaction that we're seeing more and more often where users have to rely on recall rather than recognition is with speech user interfaces. So for example, when interacting with Apple's Siri, Siri asks me what I can help you with and I need to either guess or remember what commands I can issue that will get Siri to do something for me. If I wait a certain amount of time, Siri will come back with some suggestions. Here's some things that you could ask me. What's the news for Chicago? Show me my tweets and so on and so forth. To give me some clues about the language that I can use. But ultimately, it's going to be up to me to recall how to interact with Siri. Because I can't recognize it from things that I see on the screen or for things that Siri says to me. So to sum up, we want to use recognition, not recall wherever possible. And if recall is required ask yourself, is it realistic to expect users to remember what you're asking them to remember? And are cues provided if recall fails?
