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One of the top10 usability heuristicsadvises to promote recognition over recall in user-interface design. What are recognition and recall and why is recognition better than recall?
心理学家喜欢在两种类型的内存检索之间进行区分：识别与召回。想想在街上遇见一个人。如果你以前见过她，你经常可以很容易地讲述，但是以她的名字来（如果这个人熟悉）是艰难的。第一个过程是认出(you recognize the person as familiar); the second involves记起.Recognitionrefers to our ability to “recognize” an event or piece of information as being familiar, while记起designates the retrieval of related details from memory.
To better understand the differences between recognition and recall and why recognition is preferable in user interfaces, we need to take a small excursion into how the human memory works.
Often psychologists think of memory as organized in块：基本互连单位。每个块都可以由其描述activation: a measure of how easily that chunk can be retrieved from memory. For example, your name is a chunk in memory; it has very high activation — if someone woke you up in the middle of the night and asked you what your name was, you’d be able to produce it fairly quickly. On the other hand, if you had to remember the name of your first-grade teacher, that answer would likely be harder to come up with: its activation is lower.
The activation of a chunk is influenced by three different factors:
- 实践: how many times a chunk has been used in the past
- Recency: how recently a chunk has been used
- Context: what is present in the person’s focus of attention
We’ll briefly review each of these individually.
常见的lore说practicemakes perfect. Indeed, the more you practice a piece of information, the more likely you are to remember it: a chunk’s activation depends on the amount of practice that it has received. That’s part of the reason why your name is so much more familiar than that of your first-grade teacher: it has received a lot more practice.
但实践不是影响激活的唯一影响：recency, or how far away in the past you’ve used a chunk, also dictates how well you remember information. In other words, something that you’ve used very recently has a higher activation than a piece of information that has not been used for a while (like the name of your first-grade teacher).
Besides practice and recency, the third factor that affects activation iscontext. To understand what that means, we need to take a step back and talk about associations.
In the beginning of this section, we said that chunks are interconnected memory units. The connection between two chunks is calledassociation. If I say the wordParisand ask you to tell me what words come to mind when you hear it, you may come up withFrance,food, Eiffel Tower,orNapoleon.All these words are strongly associated withParis, and whenParisgets in the focus of attention (that is, you’ve just heard it or read it), it spreads activation to other chunks associated to it. The most active chunk in your memory is the one selected as your first response; the next most active chunk will be your second response, and so on. (Note that the associations between concepts are highly personal and depend on previous experience: a French person may have totally different associations to the wordParis比美国人。）
The concept of association is tremendously important in psychology: it forms the basis of learning and problem solving. It allows us to have a relevant conversation and it helps us discover new things. It is the link between the present (the current context in which we are) and our previous experience and history.
(Our seminarThe Human Mind and Usabilitydiscusses the concepts of memory and activation in more detail.)
The big difference between recognition and recall is the amount of cues that can help the memory retrieval; recall involves fewer cues than recognition.
Answering a question such asDid Herman Melville write Moby Dick?involves recognition: you simply have to recognize whether the information provided is correct. If instead I asked youWho wrote Moby Dick?you would use a process of recall to retrieve the right answer from your memory.
Recognition is easier than recall because it involves more cues: all those cues spread activation to related information in memory, raise the answer’s activation, and make you more likely to pick it. It’s the reason for which multiple-choice questions are easier than open questions, where the respondent has to come up with an answer.
在日常生活中，我们经常使用识别和召回的组合来帮助我们从内存中检索信息。我们通常从一段更容易召回的信息开始缩小我们的选择，然后我们逐一地通过产生的选择并识别相关的选择。通过记住其名称并将其键入浏览器的地址栏中的一个例子。假设你想去我们的网站：如果你已经在这里了很多，你可能会记得它被称为nngroup.com并快速轻松地到达这里。但是，许多人只能回想起他们与网站关联的一些术语，例如“可用性”，“用户体验”或“Jakob Nielsen”。幸运的是，对于大多数此类条款，将它们进入一个主要的搜索引擎将把这个网站作为第一页的条目之一。这将您的任务转换为扫描SERP（搜索引擎结果页面）之一，并依赖于识别来从列出的其他选项中挑选所需的网站。（实际上，通过Eytan ADAR，Jaime Teevan和Susan Dumais的纸张表明，这种回溯前页的路径的方法是重新审视网上内容的首选方法。）
Search does require users to generate query terms from scratch — which大多数人都很糟糕,但从那时起,用户可以依靠recognition while using the search results. This is one of the reasons search engines have become such an essential tool for using the web. Search suggestions are a major advance in search usability because they partly transform the query generation task from one of recall to one of recognition.
Recall in User Interfaces
The classic example of recall in an interface is login. When you log in to a site, you have to remember both a username (or email) and a password. You receive very few cues to help you with that memory retrieval: usually, just the site itself. Some people make it easier for themselves by using the same credentials everywhere on the web. Others create a password that is related to the site (e.g., “amazonpassword” for Amazon.com or “buyshoes” on zappos.com) so that they can increase the ability of recall by making the site a stronger cue. And many othersjust keep their passwords somewhere on their computeror on a piece of paper.
Recognition in Interfaces
Promote Recognition in User Interfaces
How do you promote recognition? By making information and interface functions visible and easily accessible.
An application or a website usually has two components:
- Thechromeor the interface: namely all the buttons, navigation, and other elements that are there to help the user reach his goal
You can make both the content and the interface easy to remember; both can benefit from designing for recognition rather than recall. We’ll look at a few successful and less successful examples of supporting retrieval of information through recognition.
Providing access to the pages recently visited and searches performed in the near past can help users resume tasks that they left incomplete and that may have a hard time recalling. Search engines such as Google and Bing often help users retrace their searches by providing past histories.
Amazon (and many other ecommerce websites) shows users lists of items that they visited recently. These lists help users remember to finish a purchase that they may have started a few days ago. They promote recognition, because users don’t need to remember interesting information that they may have seen in the past or recall what that product might have been called.
Other tools that let users save information in an app or on a website (favorites,wish lists, shopping lists, etc.) all help with making content easily accessible via recognition.
Visible, Intuitive Chrome
Command-line interfaces are an example of interfaces that are based on recall. If you want to rename a file calledmyfilein a UNIX system, you would have to type the commandmvmyfile你的文件. You would have to recall not only thatmv是移动的命令，还可以是参数的正确顺序。
When direct manipulation and WYSIWYG came around, the idea was to replace some of these commands with actions that would be intuitive, so people would not need to recall anything from memory. The other alternative to command language was based on buttons and menus: the available commands would be visible in the interface and users will be able to select them.Gestural interfacesmove us back to the era of recall, because they require users to remember the gestures that they can make in a given context. Tips, progressive disclosure, and good gestural affordances are all cues that are meant to help users with this extra memory burden by providing extra cues to make the recall of the gesture easier. (You can learn more about interaction styles, including direct manipulation, in our class on每个设计师必须知道的用户界面原则.)
Many mobile apps start with tutorialsthat explain to users how they are supposed to use the apps. People are supposed to memorize that information and remember it when they need it. That’s not going to happen: tutorials have a lot of information, but they are not rehearsed much and users have little time to establish associations between the information in the tutorial and the actual interface. Instead of showing general tutorials, use tips that are tailored to the page that the user is visiting. Those will allow the user to recognize which actions they may want to do and how.
How easily information can be retrieved from memory depends on how often we’ve encountered that information, how recently we’ve used, and how much it is related to the current context. Richer contexts (like those present when we use recognition rather than recall) make memory retrieval easier. Interfaces that promote recognition give users extra help in remembering information, be it about tasks and items that they had seen before or about interface functionality.