The Design of Everyday Things经典读后感有感

《The Design of Everyday Things》是一本由Donald A. Norman著作，Basic Books出版的Paperback图书，本书定价：USD 16.95，页数：272，特精心收集的读后感，希望对大家能有帮助。

《The Design of Everyday Things》读后感(一)：科技以懒人为本

伍迪·艾伦的一部片子中，伍迪扮演的Jack家淋浴器去开的时候没水出来，去打开洗脸池的水龙头的时候，浴缸水出来了，再去按按钮冲马桶的时候，淋浴的莲蓬头出水了。整个一指东打西。上次我和Longman去老师家，居然淋浴器无法使用。就那么几个控制的地方，转也不出水，拉也不出水，拧也不出水。Longman是教授、博士，我想总归比我聪明一些吧，让我高兴的是，他也打不开。夜深了，也不好吵醒主人，只好不洗澡了。不过，人生最悲惨的事不是放不了水洗不成澡，而是不小心打开了被烫伤。

看过《日常事物的设计》一书后，遇到这种问题，我从来不自责。按照书上的道理，我总是对的，厂家的设计总有错的。如需进一步了解这种歪理邪说，参见这一篇关于睡觉和床的科普文章。这几天在安装一套录像监控系统，发觉这个说明书也够呛。总之我按照它的指示拆来装去，后来反正是给折腾出来了，只是到现在为止，我并不知道多出来的两颗螺丝钉是从哪里来的。

以前我们看产品，大家看的是功能、性能，现在，都讲究个设计、用户体验了。这在手机大战中体现得最明显，从黑莓到iphone再到微软的Windows Mobile，现在大家争的是设计。设计得越来越白痴。年轻学生中有个说法：看说明书才能用的产品，我是不会用的。

我发觉老师更是这样。去年有个老师提出了一个要求，说有些课程是大课，无法知道学生出勤情况，于是我们想了个办法，设计了一个点名的手机软件。用起来特别简单：老师设置一个考勤时间，设置一个密码，上课的时候公布密码，学生用手机输入密码，输对了，他的名字就从“不在场”的名单里自动清除。我下午给一个老师讲述这个用法，这位老师说：怎么这么复杂？能不能借助手机的GPS功能，自动感知学生是否在场呢？

怪不得爱迪生这么说呢：需要是发明之父，懒惰是发明之母。

《The Design of Everyday Things》读后感(二)：睡觉不好怪床歪

去药房拿药回来，夫人问：你有没有问这药是怎么吃的？

我回答说：用嘴吃。

结果被臭骂一顿。我觉得冤枉。我的想法是这个问题还用问吗？这种小孩子吃的维生素又不是处方药，医生甚至没有给医嘱，那药瓶上还能不写吗？

我于是拿出药瓶，左看右看，只写着一次吃1.0毫升。

是一天1.0毫升，每六小时，还是一星期？对方辩友问。

我又拿出夹在里面的说明书，然后再看纸盒子，左看右看上看下看，就是找不到是每隔多久吃一次的任何信息，虽然每个能写字的地方都写得满满的。

最后我只好打电话问医生，才把问题给解决。

如果是以往发生这种问题，我不用劳动我们家那位的口舌，我自己都会骂自己的愚蠢。

但最近我天天做研究，不仅学问的功力大增，而且看问题的角度也不一样了。我发现这并不是我的问题，而是它药厂的设计的问题。

创办数字设备公司（DEC）的Kenneth Olsen在公司的年度会议上无奈地宣布，他一直没有搞懂如何用公司的微波炉来热咖啡。《日常事物的设计》（The Design of Everyday Things）一书作者Donald Norman的一个朋友买了个电子表，老半天都调不好，无奈地摇头说：要把这表调对，得有麻省理工的工科硕士学位才行。Norman说正是，我就是麻省理工的工科硕士，可我也调不对。不会用微波炉热咖啡的Olsen拥有麻省理工的两个工科硕士学位。

如果我们觉睡不好，那一般有两种可能。一种是你有个刚出生的孩子，动不动就哭，而且你有一个更大一点的孩子，一听有人哭马上跟进，银瓶乍破水浆迸，大珠小珠落玉盘。另外一种可能，就是你的床真是歪了。不是你睡觉的问题，而是床的设计问题。

设计是一门很大的学问。它是设计者和使用者通过产品实现的无声的交流。按照《日常事物的设计》一书的说法，好的设计应该具备如下特征：

Affordances: 就是事物的实际功用，以及我们对其功用的常见解释。比如一个矮矮的敞口的容器，就很有可能被看成烟灰缸，虽然你可能是想把它设计成笔筒。刀形的东西，我们就想着用它来切东西。思维有一定的定势，除非你有别的方法将这定势打破，否则你最好顺应潮流，按照这定势来设计，如果你不希望有人把烟灰弹入你的笔筒的话。

Constraints: 你给使用者增加限制，使得他犯不成错误。比如电脑的各种接口，最好设计成一个萝卜一个坑，你想插错都难。

Mapping: 对应性。现在新出来的电话的功能多如牛毛，但如果你不去玩它，有很多功能就会废弃不用。因为有些功能是数字组合而成的，而这种组合是一种人工的，随机的组合，并不能在用户的头脑里形成自然的对应。

Feedback: 反馈。使用者采取了某个行动，会有及时、明显的反馈。其实汽车上的各种功能要比各种新的电话少，但是掌握起来，失误却少得多。因为汽车上的每个功能你如果执行起来，都会有即刻的反馈。而你打电话时候按错了某个复杂的键，拨给一个错误的人，你或许只有等对方接听电话的时候才发觉。

《日常事物的设计》一书封面上有一只茶壶，茶壶的壶嘴和把手在同样一边，如果你倒茶，你很有可能就把自己烫伤。

有问题的设计几乎无处不再。有时候不出点事情，还没有人想起来去追究设计者的责任。有个笨贼，偷到人家的车库，结果无论如何打不开车库之门。而主人又出去度假数日。笨贼在车库里饿了几天，冻了几天，吃够苦头。主人回家后，笨贼终于逃出，头一件事就去控告车库主人，说这车库门设计不合理，造成自己身心健康蒙受损失。官司居然赢了。

我们都应该向这笨贼学习。

我并没有说你必须把自己变成笨蛋，或者小偷。

《The Design of Everyday Things》读后感(三)：关于这本书是如何毁掉我的生活的

这两周的心路历程是这样的：读完前几章的时候，走在路上没事儿就瞟各种门是如何开关的，于是再也分不清pull&push以及各种自动门， 读完整本书的时候，看所有的水龙头都觉得别扭。That sucks. 不过整个阅读过程还是十分令人愉悦的，200页的小册子读起来并不费劲。在我看来，整本书中最为重要的一个概念在于seven stages of action：Seven Stages of Action constitute three stages of execution, three stages of evaluation and our goals. 1. Forming the goal 2. Forming the intention 3. Specifying an action 4. Executing the action 5. Perceiving the state of the world 6. Interpreting the state of the world 7. Evaluating the outcome 其中2-4大致是说execute的过程，5-7说的是evaluate的过程。 wiki上的说明倒是十分详细：http://en.wikipedia.org/wiki/Seven_stages_of_action 其实不太明白form the goal和form the intention之间到底有多大的区别，不过我觉着了解人的行为过程，并且理解了两个gulfs (the gulf of execution and the gulf of evaluation)就明白了大多数情况下糟糕的用户体验来源于何处。同时这也为designer提供了一个很好的解决问题的思路。Norman在第一章里说到好的user experience需要提供visibility, a good conceptual model, good mappings and feedback其实说的也就是这个。Visibility, good conceptual model, good mappings都有助于减少the gulf of execution, 而feedback很好的帮助用户了解他们的行为产生了怎样的效果。而其他的讨论，比如人是如何构建自己的knowledge and memory, 并且如何根据已有经验和记忆做出相关的行为，为何recognize要优于recall，好的设计应该如何减少或应对用户可能出现的错误等等，在我看来也都是基于了这两个方面。 我一直觉得所谓don't make me think其实并不是完全让用户放弃思考，而是don't make me surprise，也就是设计符合用户心理模型的交互流程，别让他们感到意外，即使让他们意外了，也尽量别让他们的出错，即使他们出错了，也别造成不可逆的后果。 Some thoughts: Norman在书里提到的例子有些实在是太老了，比如电话系统，实在是难以感同身受，而另一些产品设计中的问题比如各种门和水龙头，现在依然还广泛地存在着。10月份要出新版本，不知道会有怎样的更新。 More thoughts: 书里关于糟糕的用户体验产生的原因阐述的十分详细，并且给出了十分high level的解决思路，不过遗憾的是Norman并没有给出详细具体的解决方案。 Evan more thoughts: 书里面很多细节还是很有趣的，偷懒了没有做笔记，找机会再读吧。

《The Design of Everyday Things》读后感(四)：从阿里巴巴的芝麻开门到网站的设计

很久很久以前，世上还没有免费电子信箱的时候，有两个同胞弟兄，一个叫阿里巴巴，一个叫高西木。同胞不同命，高西木同志嫁给了有钱人的女儿，所以发财了。阿里巴巴却依旧是个穷人，只有上山砍柴，无意中发现里四十大盗的藏宝洞。藏宝洞有个密码，叫“芝麻，芝麻，开门。”

这个秘密被高西木发现。高西木用密码打开了门，但一看到数不清的钱财，立刻就傻眼了，把密码忘记了。“大麦，大麦，开门。”他说。门不开。“小麦，小麦，开门。”门依然不开。等他终于想起来的时候，四十大盗已经回来了，立刻把他砍死。

这个故事有很多寓意，比如人不能太有钱，否则有可能被强盗砍死。我就没有这个问题，当然，您实在痛苦的话，不如把钱给我，我乐意为您分忧。

但是这个故事却让我想到了电子邮件信箱。在古老的网络泡沫期，不知道涌现出多少个免费的电子邮件信箱。和大家一样，我也申请了无数个，163, hotmail, 雅虎，新浪，等等。那也是古时候的事情了。当时我还没有USB接口的外置存储器（JumpDrive），没有刻录机，也没有Zip Disk, 除了可怜的1.44寸的磁盘，我从一个电脑换到另外一个电脑，转移文件的方法只有通过免费电子邮件。在那黑暗的时代，电子邮箱的存储空间也是有限的，只有一两兆，多点的是四兆，我一个PowerPoint文件就可能一兆多。想多点空间就只有交钱。我不像高西木那样富有，所以只好多申请几个免费的。

信箱的密码各商家的规定却很不一样，有的要求你4位以上，有的6位以上，有的7位以上。有的数字就行了，有的字母就行了，有的是数字加字母。我哪里记得住。所以有时候就借助于“提示问题”。比如我的提示问题是：“小学一年级在操场上和你打了一架的那人的绰号是什么？”我当初设置的答案可能是“大头”。后来去找密码，问题就跟着出来了。当电脑问我：“小学一年级在操场上和你打了一架的那人的绰号是什么？”我发觉我陷入了高西木一样的困境。

“扁头”。

电脑说：提示信息，你的答案错误，请重新尝试。

“麻子”？

错误。

“小矮子”？

错误。

我怎么就这么喜欢在操场上打架呢？（我后来放下屠刀，立地成佛，当上了高中生，不打了。这是后话，不能帮助我破解我自己的密码。）所以除非我找到一个小学同学，把班上人的名字一一搜出来，核对绰号，否则我那些文件就只有老死在那些免费邮件的藏宝洞里。事实上正是这样。愿它们安息，在浩浩无边的网际。

有两种知识或信息。一种是在内化到头脑里的知识（knowledge in the head）.另外一种是外在的知识（knowledge in the world）。阿里巴巴记得“芝麻，芝麻，开门”，这是内化的知识。但强盗头子就没有阿里巴巴这么聪明，所以他想记住阿里巴巴住在什么地方，就只好在阿里巴巴门上划个记号，这是“外在的知识”。外在知识所见所得，但是也容易改。聪明的阿里巴巴一看记号，立刻把所有的房子外面都划上同样的记号。强盗头子又找不着北了。当个强盗其实也不容易。

一个设计者，是教育设计者也好，是免费电子信箱的设计者也好，就必须决定，我们如何让我们的用户（学生，上网者）以比较简便的方法，获取到我们需要得到的信息。我们如果能记住某个密码，那它是内在的知识。可惜如今信息爆炸，信用卡借计卡电子邮件信箱网上书店同学录MSN, QQ, 需要记住的密码实在太多，甚至帐户名也太多，常用的倒没有问题，不常用的，就得有些外在的提示。然而你得对外在的提示也加也一定的限制，最好形成自然的对应（natural mapping）。比如亚马逊网上书店，就没有让你重新设置一个帐号，而是让你用电子邮件作为帐号，这就是一种比较自然的对应，你就很少有进入的难题。电话公司核对信息，用的是地址和邮编，也不需要重新去想密码的问题。

但是这些信息小偷也很容易获取的，怎么办？比如信用卡的盗用事件。很多信用卡公司用“妈出嫁前的名字”（婚后一般随夫姓）作为密码，因为这种信息是从电话号码本或者网络上都查不到。可惜遇到华人就麻烦，中华女子，是嫁不改姓的。不过如果像香港那样如何，两个姓都用？

“请您说出的姓氏？”

“Zhaowangshi (赵王氏。)”

这样美国的小偷就没辄了。小偷不是跨国公司的经理人，一般都没有接受过跨文化交流的培训。知道你这么复杂，他就去偷Smith们，Mary们的帐户了。

外在的信息和内化的信息的优劣，也是看情况的。我们没钱的人还好，不要多操心，有钱的人真是麻烦。银行密码太简单吧，人家能猜到。太复杂吧，又记不住。当然，有钱人可以聪明一些，把保险柜密码伪装起来，藏到某个不容易发现的地方，比如记在通讯录里：“钱贵，电话：020-1234567。”

这也不保险。《日常事物的设计》一书里说，有个悔过自新的罪犯称，他去偷东西，头一件事就找通讯录，因为大部分人都把银行帐户的信息放在通讯录里。

所以说到底，人们不应该天天为钱操心，这是一种极其愚蠢的做法。人们应该把时间花在写博客、写豆瓣书评上面，这才是人间正道。

《The Design of Everyday Things》读后感(五)：全书摘抄

Design of Everyday Things (Norman, Don)

- 您在位置 #129-140的标注 | 添加于 2014年10月10日星期五 下午1:26:57

Consider the thermostat. When some people enter a cold house, they turn the thermostat to a very high temperature in order to reach the desired level more quickly. They do this because of their internal mental model of how the furnace works. The model is sensible and coherent, even if not well thought out. It is also wrong. But how would they know？ Although this behavior is wrong for the home, it works for most automobiles—turn the heat or air conditioning up all the way, and when the interior is at the correct temperature, adjust the temperature control again. To understand how to use things, we need conceptual models of how they work. Home furnaces, air conditioners, and even most household ovens have only two levels of operation: full power or off. Therefore, they are always heating or cooling to the desired temperature as rapidly as possible. In these cases, setting the thermostat too high does nothing but waste energy when the temperature overshoots the target. Now consider the automobile. The conceptual model is quite different. Yes, the heater and air conditioner also have only two settings, full power or off, but in many autos, the desired temperature is achieved by mixing cold and hot air. In this case, faster results come by turning off the mixing (by setting the temperature control to an extreme) until the desired temperature is reached, then adjusting the mixture to maintain the desired temperature.

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Design of Everyday Things (Norman, Don)

- 您在位置 #465-466的标注 | 添加于 2014年10月13日星期一 下午2:13:45

Something that happens right after an action appears to be caused by that action.

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Design of Everyday Things (Norman, Don)

- 您在位置 #468-469的标注 | 添加于 2014年10月13日星期一 下午2:15:14

When an action has no apparent result, you may conclude that the action was ineffective. So you repeat it.

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Design of Everyday Things (Norman, Don)

- 您在位置 #485-487的标注 | 添加于 2014年10月13日星期一 下午2:21:36

Irving Biederman, a psychologist who studies visual perception, estimates that there are probably “30,000 readily discriminable objects for the adult.”5

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Design of Everyday Things (Norman, Don)

- 您在位置 #519-522的标注 | 添加于 2014年10月13日星期一 下午2:30:09

For everyday things, conceptual models need not be very complex. After all, scissors, pens, and light switches are pretty simple devices. There is no need to understand the underlying physics or chemistry of each device we own, simply the relationship between the controls and the outcomes. When the model presented to us is inadequate or wrong (or, worse, nonexistent), we can have difficulties.

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Design of Everyday Things (Norman, Don)

- 您在位置 #546-550的标注 | 添加于 2014年10月13日星期一 下午2:37:55

The design model is the designer’s conceptual model. The user’s model is the mental model developed through interaction with the system. The system image results from the physical structure that has been built (including documentation, instructions, and labels). The designer expects the user’s model to be identical to the design model. But the designer doesn’t talk directly with the user—all communication takes place through the system image. If the system image does not make the design model clear and consistent, then the user will end up with the wrong mental model.

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Design of Everyday Things (Norman, Don)

- 您在位置 #623-625的标注 | 添加于 2014年10月13日星期一 下午11:52:30

The “R” button is kind of a vestigial feature. It is very hard to remove features of a newly designed product that had existed in an earlier version. It’s kind of like physical evolution. If a feature is in the genome, and if that feature is not associated with any negativity (i.e., no customers gripe about it), then the feature hangs on for generations.

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Design of Everyday Things (Norman, Don)

- 您在位置 #646-651的标注 | 添加于 2014年10月14日星期二 上午12:02:36

Whenever the number of possible actions exceeds the number of controls, there is apt to be difficulty. The telephone system has twenty-four functions, yet only fifteen controls—none of them labeled for specific action. In contrast, the trip computer for the car performs seventeen functions with fourteen controls. With minor exceptions, there is one control for each function. In fact, the controls with more than one function are indeed harder to remember and use. When the number of controls equals the number of functions, each control can be specialized, each can be labeled. The possible functions are visible, for each corresponds with a control. If the user forgets the functions, the controls serve as reminders.

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Design of Everyday Things (Norman, Don)

- 您在位置 #654-656的标注 | 添加于 2014年10月14日星期二 上午12:03:31

Visibility acts as a good reminder of what can be done and allows the control to specify how the action is to be performed. The good relationship between the placement of the control and what it does makes it easy to find the appropriate control for a task. As a result, there is little to remember.

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Design of Everyday Things (Norman, Don)

- 您在位置 #776-777的标注 | 添加于 2014年10月14日星期二 下午2:29:57

The development of a technology tends to follow a U-shaped curve of complexity: starting high; dropping to a low, comfortable level; then climbing again.

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Design of Everyday Things (Norman, Don)

- 您在位置 #777-779的标注 | 添加于 2014年10月14日星期二 下午2:31:18

New kinds of devices are complex and difficult to use. As technicians become more competent and an industry matures, devices become simpler, more reliable, and more powerful. But then, after the industry has stabilized, newcomers figure out how to add increased power and capability, but always at the expense of added complexity and sometimes decreased reliability.

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Design of Everyday Things (Norman, Don)

- 您在位置 #862-865的标注 | 添加于 2014年10月15日星期三 上午7:29:49

If an error is possible, someone will make it. The designer must assume that all possible errors will occur and design so as to minimize the chance of the error in the first place, or its effects once it gets made. Errors should be easy to detect, they should have minimal consequences, and, if possible, their effects should be reversible.

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Design of Everyday Things (Norman, Don)

- 您在位置 #877-879的标注 | 添加于 2014年10月15日星期三 上午7:36:16

Of course, Newton and his successors assume the absence of friction and air. Aristotle lived in a world where there was always friction and air resistance. Once friction is involved, then objects in motion tend to stop unless you keep pushing. Aristotle’s theory may be bad physics, but it describes reasonably well what we can see in the real world.

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Design of Everyday Things (Norman, Don)

- 您在位置 #950-958的标注 | 添加于 2014年10月18日星期六 下午1:51:29

One major aspect of the assignment of blame is that we frequently have little information on which to make the judgment, and what little we have may be wrong. As a result, blame or credit can be assessed almost independently of reality. Here is where the apparent simplicity of everyday objects causes problems. Suppose I try to use an everyday thing, but I can’t: Where is the fault, in my action or in the thing？ We are apt to blame ourselves. If we believe that others are able to use the device and if we believe that it is not very complex, then we conclude that any difficulties must be our own fault. Suppose the fault really lies in the device, so that lots of people have the same problems. Because everyone perceives the fault to be his or her own, nobody wants to admit to having trouble. This creates a conspiracy of silence, maintaining the feelings of guilt and helplessness among users. Interestingly enough, the common tendency to blame ourselves for failures with everyday objects goes against the normal attributions people make. In general, it has been found that people attribute their own problems to the environment, those of other people to their personalities.

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Design of Everyday Things (Norman, Don)

- 您在位置 #972-974的标注 | 添加于 2014年10月18日星期六 下午1:55:49

It seems natural for people to blame their own misfortunes on the environment. It seems equally natural to blame other people’s misfortunes on their personalities. Just the opposite attribution, by the way, is made when things go well.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1057-1065的标注 | 添加于 2014年10月25日星期六 下午1:50:39

To get something done, you have to start with some notion of what is wanted—the goal that is to be achieved. Then, you have to do something to the world, that is, take action to move yourself or manipulate someone or something. Finally, you check to see that your goal was made. So there are four different things to consider: the goal, what is done to the world, the world itself, and the check of the world. The action itself has two major aspects: doing something and checking. Call these execution and evaluation (figure 2.2). Real tasks are not quite so simple. The original goal may be imprecisely specified—perhaps “get something to eat,” “get to work,” “get dressed,” “watch television.” Goals do not state precisely what to do—where and how to move, what to pick up. To lead to actions goals must be transformed into specific statements of what is to be done, statements that I call intentions. A goal is something to be achieved, often vaguely stated. An intention is a specific action taken to get to the goal. Yet even intentions are not specific enough to control actions.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1088-1093的标注 | 添加于 2014年10月25日星期六 下午1:59:31

Seven stages of action: one for goals, three for execution, and three for evaluation. • Forming the goal • Forming the intention • Specifying an action • Executing the action • Perceiving the state of the world • Interpreting the state of the world • Evaluating the outcome

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Design of Everyday Things (Norman, Don)

- 您在位置 #1187-1198的标注 | 添加于 2014年11月9日星期日 上午10:14:30

Precise behavior can emerge from imprecise knowledge for four reasons. 1. Information is in the world. Much of the information a person needs to do a task can reside in the world. Behavior is determined by combining the information in memory (in the head) with that in the world. 2. Great precision is not required. Precision, accuracy, and completeness of knowledge are seldom required. Perfect behavior will result if the knowledge describes the information or behavior sufficiently to distinguish the correct choice from all others. 3. Natural constraints are present. The world restricts the allowed behavior. The physical properties of objects constrain possible operations: the order in which parts can go together and the ways in which an object can be moved, picked up, or otherwise manipulated. Each object has physical features—projections, depressions, screwthreads, appendages—that limit its relationships to other objects, operations that can be performed to it, what can be attached to it, and so on. 4. Cultural constraints are present. In addition to natural, physical constraints, society has evolved numerous artificial conventions that govern acceptable social behavior. These cultural conventions have to be learned, but once learned they apply to a wide variety of circumstances.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1197 的笔记 | 添加于 2014年11月9日星期日 上午10:15:33

interface between human and world

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Design of Everyday Things (Norman, Don)

- 您在位置 #1197 的笔记 | 添加于 2014年11月9日星期日 上午10:17:13

interface between human and world

dance with shackles on

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Design of Everyday Things (Norman, Don)

- 您在位置 #1211-1212的标注 | 添加于 2014年11月9日星期日 上午10:24:21

Whenever information needed to do a task is readily available in the world, the need for us to learn it diminishes.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1231 的笔记 | 添加于 2014年11月9日星期日 上午10:43:28

to compare horizontally and only to find the differences

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Design of Everyday Things (Norman, Don)

- 您在位置 #1230-1231的标注 | 添加于 2014年11月9日星期日 上午10:43:29

in normal life, we have to distinguish between the penny and other U.S. coins, not between several versions of one denomination.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1232-1239的标注 | 添加于 2014年11月9日星期日 上午10:44:52

People function through their use of two kinds of knowledge: knowledge of and knowledge how. Knowledge of—what psychologists call declarative knowledge—includes the knowledge of facts and rules. “Stop at red lights.” “New York City lies on a parallel a bit south of Madrid, San Diego’s longitude is east of Reno.” “To get the key out of the ignition, the car must be in reverse.” Declarative knowledge is easy to write down and to teach. Knowledge how—what psychologists call procedural knowledge—is the knowledge that enables a person to perform music, to stop a car smoothly with a flat tire on an icy road, to return a serve in tennis, or to move the tongue properly when saying the phrase “frightening witches.” Procedural knowledge is difficult or impossible to write down and difficult to teach. It is best taught by demonstration and best learned through practice. Even the best teachers cannot usually describe what they are doing. Procedural knowledge is largely subconscious.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1243-1244的标注 | 添加于 2014年11月9日星期日 上午10:46:41

We place items in specific locations as reminders. In general, people structure the environment to provide a considerable amount of the information required for something to be remembered.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1534-1539的标注 | 添加于 2015年1月1日星期四 上午10:29:31

A good reminding method is to put the burden on the thing itself. Do my neighbors want me to take them to the airport？ Fine, but they have to call me up the night before and remind me. Do I want to remember to take a book to the university to give to a colleague？ I put the book someplace where I cannot fail to see it when I leave the house. A good spot is against the front door of the house. I can’t leave without tripping over the book. If I am at a friend’s house and I borrow a paper or a book, I remember to take it by putting my car keys on it. Then when I leave, I am reminded. Even if I forget and go out to my car, I can’t drive away without the keys.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1544-1545的标注 | 添加于 2015年1月1日星期四 上午10:29:40

The ideal reminder has to have both components: the signal that something is to be remembered, the message of what it is.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1595-1597的标注 | 添加于 2015年1月1日星期四 上午10:34:58

If a design depends upon labels, it may be faulty. Labels are important and often necessary, but the appropriate use of natural mappings can minimize the need for them. Wherever labels seem necessary, consider another design.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1616-1618的标注 | 添加于 2015年1月1日星期四 上午10:40:03

Knowledge (or information) in the world and in the head are both essential in our daily functioning. But to some extent we can choose to lean more heavily on one or the other. That choice requires a trade off—gaining the advantages of knowledge in the world means losing the advantages of knowledge in the head (figure 3.6).

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Design of Everyday Things (Norman, Don)

- 您在位置 #1579-1579的标注 | 添加于 2015年1月1日星期四 上午10:40:32

We can see that the number of possible sequences has been reduced from twenty-four to one.16

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Design of Everyday Things (Norman, Don)

- 您在位置 #1618 的笔记 | 添加于 2015年1月1日星期四 上午10:46:30

brain and external tools like evernote

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Design of Everyday Things (Norman, Don)

- 您在位置 #1634-1636的标注 | 添加于 2015年1月1日星期四 上午10:48:30

Knowledge in the world is easier to learn, but often more difficult to use. And it relies heavily upon the continued physical presence of the information; change the environment and the information is changed. Performance relies upon the physical presence of the task environment.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1635 的笔记 | 添加于 2015年1月1日星期四 上午10:50:54

ui and user guide, a serie of continuous interactions

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Design of Everyday Things (Norman, Don)

- 您在位置 #1667-1667的标注 | 添加于 2015年1月1日星期四 上午11:09:27

Affordances suggest the range of possibilities, constraints limit the number of alternatives.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1942-1944的标注 | 添加于 2015年2月15日星期日 下午5:46:43

It does not take much examination to discover the reason for the difficulties: there is no visual feedback. As a result, users (1) have trouble remembering their place in the lengthy sequence of required steps; (2) have trouble remembering what next needs to be done; and (3) cannot easily check the information just entered to see if it is what was intended, and then cannot easily change it, if they decide it is wrong.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1989-1990的标注 | 添加于 2015年2月15日星期日 下午6:03:07

real, natural sound is as essential as visual information because sound tells us about things we can’t see, and it does so while our eyes are occupied elsewhere.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1988-1994的标注 | 添加于 2015年2月15日星期日 下午6:05:01

Bill Gaver, who has been studying use of sound in my laboratory, points out that real, natural sound is as essential as visual information because sound tells us about things we can’t see, and it does so while our eyes are occupied elsewhere. Natural sounds reflect the complex interaction of natural objects: the way one part moves against another; the material of which the parts are made—hollow or solid, metal or wood, soft or hard, rough or smooth. Sounds are generated when materials interact, and the sound tells us whether they are hitting, sliding, breaking, tearing, crumbling, or bouncing. Moreover, sounds differ according to the characteristics of the objects, according to their size, solidity, mass, tension, and material. And they differ with how fast things are going and how far away from us they are.

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Design of Everyday Things (Norman, Don)

- 您在位置 #1999-2003的标注 | 添加于 2015年2月15日星期日 下午6:07:12

You have to be very careful with sound, however. It easily becomes cute rather than useful. It can annoy and distract as easily as it can aid. One of the virtues of sounds is that they can be detected even when attention is applied elsewhere. But this virtue is also a deficit, for sounds are often intrusive. Sounds are difficult to keep private unless the intensity is low or earphones are used. This means both that neighbors may be annoyed and that others can monitor your activities. The use of sound to convey information is a powerful and important idea, but still in its infancy.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2031-2035的标注 | 添加于 2015年2月15日星期日 下午6:20:29

Errors come in several forms. Two fundamental categories are slips and mistakes. Slips result from automatic behavior, when subconscious actions that are intended to satisfy our goals get waylaid en route. Mistakes result from conscious deliberations. The same processes that make us creative and insightful by allowing us to see relationships between apparently unrelated things, that let us leap to correct conclusions on the basis of partial or even faulty evidence, also lead to error.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2038-2042的标注 | 添加于 2015年2月15日星期日 下午6:21:35

The differences between slips and mistakes are readily apparent in the analysis of the seven stages of action. Form an appropriate goal but mess up in the performance, and you’ve made a slip. Slips are almost always small things: a misplaced action, the wrong thing moved, a desired action undone. Moreover, they are relatively easy to discover by simple observation and monitoring. Form the wrong goal, and you’ve made a mistake. Mistakes can be major events, and they are difficult or even impossible to detect—after all, the action performed is appropriate for the goal.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2049-2053的标注 | 添加于 2015年2月15日星期日 下午6:27:16

Slips show up most frequently in skilled behavior. We don’t make so many slips in things we are still learning. In part, slips result from a lack of attention. On the whole, people can consciously attend to only one primary thing at a time. But we often do many things at once. We walk while we talk; we drive cars while we talk, sing, listen to the radio, use a telephone, take notes, or read a map. We can do more than one thing at a time only if most of the actions are done automatically, subconsciously, with little or no need for conscious attention.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2060-2061的标注 | 添加于 2015年2月15日星期日 下午6:28:55

We can place slips into one of six categories: capture errors, deｓｃｒｉｐｔion errors, data-driven errors, associative activation errors, loss-of-activation errors, and mode errors.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2070-2072的标注 | 添加于 2015年2月15日星期日 下午6:33:29

The capture error appears whenever two different action sequences have their initial stages in common, with one sequence being unfamiliar and the other being well practiced. Seldom, if ever, does the unfamiliar sequence capture the familiar one.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2076-2085的标注 | 添加于 2015年2月15日星期日 下午6:37:01

In the common slip known as the deｓｃｒｉｐｔion error, the intended action has much in common with others that are possible. As a result, unless the action sequence is completely and precisely specified, the intended action might fit several possibilities. Suppose that my tired student in the example formed a mental deｓｃｒｉｐｔion of his intended action something like “throw the shirt into the opening at the top of the container.” This deｓｃｒｉｐｔion would be perfectly unambiguous and sufficient were the laundry basket the only open container in sight; but when the open toilet was visible, its characteristics matched the deｓｃｒｉｐｔion and triggered the inappropriate action. This is a deｓｃｒｉｐｔion error because the internal deｓｃｒｉｐｔion of the intention was not sufficiently precise. Deｓｃｒｉｐｔion errors usually result in performing the correct action on the wrong object. Obviously, the more the wrong and right objects have in common, the more likely the errors are to occur. Deｓｃｒｉｐｔion errors, like all slips, are more likely when we are distracted, bored, involved in other activities, under extra stress, or otherwise not inclined to pay full attention to the task at hand. Deｓｃｒｉｐｔion errors occur most frequently when the wrong and right objects are physically near each other. People have reported a number of deｓｃｒｉｐｔion errors to me.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2124-2129的标注 | 添加于 2015年2月15日星期日 下午6:49:30

Mode errors occur when devices have different modes of operation, and the action appropriate for one mode has different meanings in other modes. Mode errors are inevitable any time equipment is designed to have more possible actions than it has controls or displays, so the controls must do double duty. Mode errors are especially likely where the equipment does not make the mode visible, so the user is expected to remember what mode has been established, sometimes for many hours. Mode errors are common with digital watches and computer systems (especially text editors). Several accidents in commercial aviation can be attributed to mode errors, especially in the use of the automatic pilots (which have a large number of complex modes).

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Design of Everyday Things (Norman, Don)

- 您在位置 #2144-2156的标注 | 添加于 2015年2月15日星期日 下午7:11:13

Suppose I were driving my car to the bank. At any given moment, the action being performed could be described at many different levels: • Driving to the bank • Turning into the parking lot • Making a right turn • Rotating the steering wheel clockwise • Moving my left hand upward and to the right and my right hand downward • Increasing the tension on the sternocostal portion of the pectoralis major muscle All these levels are active at the same time. The most global deｓｃｒｉｐｔion (the one at the top of the list), is called the high-level specification. The more detailed deｓｃｒｉｐｔions, the ones at the bottom of the list, are called the low-level specifications. Any one of them might be in error. It is often possible to detect that the result of an action is not as planned, but then not to know at which level of specification the error has taken place. Problems of level commonly thwart the correction of error. My collection of slips includes several examples in which a person detects a problem but attempts to correct it at the wrong level.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2157-2161的标注 | 添加于 2015年2月15日星期日 下午7:12:16

One frequent example is the nonworking key, reported to me both for cars and homes. Someone goes to his or her car and the key won’t work. The first response is to try again, perhaps holding the key more level or straight. Then the key is reversed, tried upside down. When that fails, the key is examined and perhaps another tried in its stead. Then the door is wiggled, shaken, hit. Finally, the person decides that the lock has broken, and walks around the car to try the other door, at which point it is suddenly clear that this is the wrong car.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2204-2204的标注 | 添加于 2015年2月15日星期日 下午7:21:07

When you build an error-tolerant mechanism, people come to rely upon it, so it had better be reliable.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2227-2239的标注 | 添加于 2015年2月20日星期五 下午10:35:10

Another theory is based on the filing cabinet model, wherein there are lots of cross references and pointers to other records. This theory has a good deal going for it, and it is probably a reasonable characterization of the most prominent approach today. Of course, it is not called a file cabinet theory. It goes by the names of “schema theory,” “frame theory,” or sometimes “semantic networks” and “propositional encoding.” The individual file folders are defined in the formal structure of the schemas or frames, and the connections and associations among the individual records make the structure into a vast and complex network. The essence of the theory consists of three beliefs, all reasonable and supported by considerable evidence: (1) that there is logic and order to the individual structures (this is what the schema or frame is about); (2) that human memory is associative, with each schema pointing and referring to multiple others to which it is related or that help define the components (thus the term “network”); and (3) that much of our power for deductive thought comes from using the information in one schema to deduce the properties of another (thus the term “propositional encoding”). 6 To illustrate the third concept: once I learn that all living animals breathe, I know that any live animal I will ever meet will breathe. I don’t have to learn this separately for all animals. We call this the “default value.” Unless told otherwise, anything I learn for a general concept applies to all of its instances by default. Default values do not have to apply to everything—I can learn exceptions, such as that all birds fly except for penguins and ostriches. But defaults hold true unless an exception shows otherwise. Deduction is a most useful and powerful property of human memory.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2282-2294的标注 | 添加于 2015年3月9日星期一 下午10:37:32

Consider what happens when two similar events are experienced: they merge together to form a kind of average, a “prototypical event.” This prototype governs interpretations and actions related to any other event that seems similar. What happens when something really discrepant occurs？ If it is quite different from the prototype, it still manages to maintain its identity when thrown into memory. It stands out by itself. If there were a thousand similar events, we would tend to remember them as one composite prototype. If there were just one discrepant event, we would remember it, too, for by being discrepant it didn’t get smudged up with the rest. But the resulting memory is almost as if there had been only two events: the common one and the discrepant one. The common one is a thousand times more likely, but not to the memory; in memory there are two things, and the discrepant event hardly seems less likely than the everyday one. So it is with human memory. We mush together details of things that are similar, and give undue weight to the discrepant. We relish discrepant and unusual memories. We remember them, talk about them, and bias behavior toward them in wholly inappropriate ways. What has this to do with everyday thought？ A lot. Everyday thought seems to be based upon past experiences, upon our ability to retrieve an event from the past and use it to model the present. This event-based reasoning is powerful, yet fundamentally flawed. Because thought is based on what can be recalled, the rare event can predominate.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2327-2337的标注 | 添加于 2015年3月10日星期二 下午1:43:54

SHALLOW STRUCTURES The menu of an ice cream store provides a good example of a shallow structure (figure 5.2). There are many alternative actions, but each is simple; there are few decisions to make after the single top-level choice. The major problem is to decide which action to do. Difficulties arise from competing alternatives, not from any prolonged search, problem solving, or trial and error. In shallow structures, there’s no problem of planning or depth of analysis. NARROW STRUCTURES A cookbook recipe is a good example of a narrow structure (figure 5.3). A narrow structure arises when there are only a small number of alternatives, perhaps one or two. If each possibility leads to only one or two further choices, then the resulting tree structure can be said to be narrow and deep. Just as the ice cream store menu is an example of a shallow structure, the multicourse, fixed menu meal can serve as an example of a deep structure. Although there may be many courses, for each course the diner is either automatically served the relevant dish or offered the choice of one or two dishes. The only action required is to accept one or to refuse: no deep thought is required.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2467-2474的标注 | 添加于 2015年3月10日星期二 下午2:23:41

The contrast in our understanding before and after an event can be dramatic. The psychologist Baruch Fischhoff has studied explanations given in hindsight, where events seem completely obvious and predictable after the fact but completely unpredictable beforehand.13 Fischhoff presented people with a number of situations and asked them to predict what would happen: they were correct only at the chance level. He then presented the same situation along with the actual outcome to another group of people, asking them to state how likely the outcome was: when the actual outcome was known, it appeared to be plausible and likely, whereas the others appeared unlikely. When the actual outcome was not known, the various alternatives had quite different plausibility. It is a lot easier to determine what is obvious after it has happened.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2554-2555的标注 | 添加于 2015年3月10日星期二 下午2:53:51

It is important to think through the implications of that cost—to decide whether people will deliberately disable the forcing function.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2555-2567的标注 | 添加于 2015年3月10日星期二 下午2:56:08

The history of seatbelts in autos provides a good example. Despite all the evidence that seatbelts are an effective means of saving lives, some people dislike them enough that they refuse to wear them, probably because the perceived risk is so much less than the actual, statistical risk. For a short period, the United States tried a forcing function on seatbelts: a special interlock was installed on each new car. If the driver’s and passengers’ belts were not fastened, the car would not start (and a buzzer would sound). This forcing function was so disliked that most drivers had their mechanics disconnect it. The law was quickly changed. There seemed to be three problems. First, many people did not want to wear seatbelts, and they resented the mechanical forcing function. Second, the forcing function couldn’t distinguish legitimate cases in which the seatbelt should not be buckled from illegitimate ones. Thus, if you wanted to carry a package in the passenger’s seat, the weightsensing element in the seat registered a person, so the car wouldn’t start unless the passenger seat’s buckle was fastened. Third, the mechanisms were not reliable, so they often failed—buzzing, stopping the engine, and being an overall nuisance. Those people who couldn’t figure out how to disconnect the forcing function simply buckled the belts permanently, fastening the buckle when the seat was unoccupied and stuffing it under the seat. So if a passenger really wanted to use the belt, it couldn’t be done. Moral: it isn’t easy to force unwanted behavior upon people. And if you are going to use a forcing function, make sure it works right, is reliable, and distinguishes legitimate violations from illegitimate ones.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2570-2584的标注 | 添加于 2015年3月10日星期二 下午3:01:32

In the field of safety engineering, forcing functions show up under other names, in particular as specialized methods for the prevention of accidents. Three such methods are interlocks, lockins, and lockouts. An interlock forces operations to take place in proper sequence (figure 5.4). Microwave ovens and television sets use interlocks as forcing functions to prevent people from opening the door of the oven or taking off the back of the television set without first turning off the electric power: the interlock disconnects the power the instant the door is opened or the back removed. The pin on a fire extinguisher or hand grenade and the safety on a rifle are other examples of interlocks; these forcing functions prevent the accidental use of the devices. A lockin keeps an operation active, preventing someone from prematurely stopping it. The sad stories of those who turn off word processors without first saving their work could be avoided with the use of a lockin. Suppose the on-off switch were a “soft” switch, not really disconnecting the power, but sending a signal to the program to quit, checking that all files had been saved, and then, after all the appropriate housekeeping operations had been completed, turning off the power. (Of course, a normal power switch should also exist as an override for special situations or for when a software problem causes the soft switch to fail.) A lockout device is one that prevents someone from entering a place that is dangerous, or prevents an event from occurring. A good example of a lockout occurs in stairways of public buildings, at least in the United States (figure 5.5). In cases of fire, people have a tendency to flee in panic, down the stairs, down, down, down, past the ground floor and into the basement, where they are trapped. The solution (required by the fire laws) is not to allow simple passage from the ground floor to the basement.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2758-2760的标注 | 添加于 2015年3月10日星期二 下午11:11:09

But none of these innovations takes hold because the qwerty keyboard, while deficient, is good enough. Although its antijamming arrangement no longer has mechanical justification, it does put many common letter pairs on opposing hands; one hand can be getting ready to type its letter while the other is finishing, so typing is speeded up.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2807-2811的标注 | 添加于 2015年3月10日星期二 下午11:47:57

Designers go astray for several reasons. First, the reward structure of the design community tends to put aesthetics first. Design collections feature prize-winning clocks that are unreadable, alarms that cannot easily be set, can openers that mystify. Second, designers are not typical users. They become so expert in using the object they have designed that they cannot believe that anyone else might have problems; only interaction and testing with actual users throughout the design process can forestall that. Third, designers must please their clients, and the clients may not be the users.

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Design of Everyday Things (Norman, Don)

- 您在位置 #4211-4213的标注 | 添加于 2015年3月11日星期三 下午12:02:26

Most designers today work in teams. Nonetheless, the comments I make about “the designer” apply. In fact, the better the teamwork, the more apt members are to share common modes of thinking and common sets of approaches, and thereby to fall prey simultaneously to the same problems.

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Design of Everyday Things (Norman, Don)

- 您在位置 #2912-2916的标注 | 添加于 2015年3月11日星期三 下午12:06:54

Designers have become so proficient with the product that they can no longer perceive or understand the areas that are apt to cause difficulties. Even when designers become users, their deep understanding and close contact with the device they are designing means that they operate it almost entirely from knowledge in the head. The user, especially the first-time or infrequent user, must rely almost entirely on knowledge in the world. That is a big difference, fundamental to the design.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3039-3041的标注 | 添加于 2015年3月11日星期三 下午10:10:48

The ability of conscious attention is limited: focus on one thing and you reduce your attention to others. Psychologists call the phenomenon “selective attention.” Excessive focus leads to a kind of tunnel vision, where peripheral items are ignored.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3137-3138的标注 | 添加于 2015年3月13日星期五 下午9:46:05

If you can’t put the knowledge on the device, then develop a cultural constraint: standardize what has to be kept in the head.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3187-3188的标注 | 添加于 2015年3月13日星期五 下午11:02:36

Each new feature adds yet another control, or display, or button, or instruction. Complexity probably increases as the square of the features: double the number of features, quadruple the complexity. Provide ten times as many features, multiply the complexity by one hundred.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3192 的书签 | 添加于 2015年3月13日星期五 下午11:07:12

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Design of Everyday Things (Norman, Don)

- 您在位置 #3254-3267的标注 | 添加于 2015年3月14日星期六 上午10:42:04

What is the problem？ Nothing special, just more of everything. The special powers of the computer can amplify all the usual problems to new levels of difficulty. If you set out to make something difficult to use, you could probably do no better than to copy the designers of modern computer systems. Do you want to do things wrong？ Here is what to do: • Make things invisible. Widen the Gulf of Execution: give no hints to the operations expected. Establish a Gulf of Evaluation: give no feedback, no visible results of the actions just taken. Exploit the tyranny of the blank screen. • Be arbitrary. Computers make this easy. Use nonobvious command names or actions. Use arbitrary mappings between the intended action and what must actually be done. • Be inconsistent: change the rules. Let something be done one way in one mode and another way in another mode. This is especially effective where it is necessary to go back and forth between the two modes. • Make operations unintelligible. Use idiosyncratic language or abbreviations. Use uninformative error messages. • Be impolite. Treat erroneous actions by the user as breaches of contract. Snarl. Insult. Mumble unintelligible verbiage. • Make operations dangerous. Allow a single erroneous action to destroy invaluable work. Make it easy to do disastrous things. But put warnings in the manual; then, when people complain, you can ask, “But didn’t you read the manual？”

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Design of Everyday Things (Norman, Don)

- 您在位置 #3348-3356的标注 | 添加于 2015年3月15日星期日 上午9:01:48

There are three requirements for a system to be explorable. 1. In each state of the system, the user must readily see and be able to do the allowable actions. The visibility acts as a suggestion, reminding the user of possibilities and inviting the exploration of new ideas and methods. 2. The effect of each action must be both visible and easy to interpret. This property allows users to learn the effects of each action, to develop a good mental model of the system, and to learn the causal relationships between actions and outcomes. The system image plays a critical role in making such learning possible. 3. Actions should be without cost. When an action has an undesirable result, it must be readily reversible. This is especially important with computer systems. In the case of an irreversible action, the system should make clear what effect the contemplated action will have prior to its execution; there should be enough time to cancel the plan. Or the action should be difficult to do, nonexplorable. Most actions should be cost-free, explorable, discoverable.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3361 的笔记 | 添加于 2015年3月15日星期日 上午9:05:11

elevator 's signal light and controller (up and down)

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Design of Everyday Things (Norman, Don)

- 您在位置 #3358-3361的标注 | 添加于 2015年3月15日星期日 上午9:05:11

Compare two different ways of getting a task done. One way is to issue commands to someone else who does the actual work: call this “command mode” or “third-person” interaction. The other way is to do the operations yourself: call this “direct manipulation mode” or “first-person” interaction. The difference between these two is like the difference between being driven by a chauffeur and driving an automobile yourself. These two different modes exist with computers.21

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Design of Everyday Things (Norman, Don)

- 您在位置 #3368-3369的标注 | 添加于 2015年3月15日星期日 上午9:10:35

Third-person interaction is well suited for situations in which the job is laborious or repetitive, as well as those in which you can trust the system (or other person) to do the job for you properly.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3369-3370的标注 | 添加于 2015年3月15日星期日 上午9:10:51

Sometimes it is nice to have a chauffeur. But if the job is critical, novel, or ill-specified, or if you do not yet know exactly what is to be done, then you need direct, first-person interaction.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3376-3379的标注 | 添加于 2015年3月15日星期日 上午9:12:23

When I use a direct manipulation system—whether for text editing, drawing pictures, or creating and playing games—I do think of myself not as using a computer but as doing the particular task. The computer is, in effect, invisible. The point cannot be overstressed: make the computer system invisible. This principle can be applied with any form of system interaction, direct or indirect.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3422-3430的标注 | 添加于 2015年3月15日星期日 下午1:00:25

Seven Principles for Transforming Difficult Tasks into Simple Ones How does the designer go about the task？ As I’ve argued in POET, the principles of design are straightforward. 1. Use both knowledge in the world and knowledge in the head. 2. Simplify the structure of tasks. 3. Make things visible: bridge the gulfs of Execution and Evaluation. 4. Get the mappings right. 5. Exploit the power of constraints, both natural and artificial. 6. Design for error. 7. When all else fails, standardize.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3498-3504的标注 | 添加于 2015年3月16日星期一 下午3:01:24

These first two approaches to mental aids keep the main tasks unchanged. They act as reminders. They reduce memory load by providing external memory devices (providing knowledge in the world rather than requiring it to be in the head). They supplement our perceptual abilities. Sometimes they enhance human skills sufficiently so that a job that was not possible before, or was possible only for the most highly skilled performers, becomes available to many. Don’t these so-called advances also cause us to lose valuable mental skills？ Each technological advance that provides a mental aid also brings along critics who decry the loss of the human skill that has been made less valuable. Fine, I say: if the skill is easily automated, it wasn’t essential.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3579-3581的标注 | 添加于 2015年3月16日星期一 下午3:20:26

A third problem is that the person becomes a servant of the system, no longer able to control or influence what is happening. This is the essence of the assembly line: it depersonalizes the job, it takes away control, it provides, at best, a passive or third-person experience.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3581-3588的标注 | 添加于 2015年3月16日星期一 下午3:20:32

All tasks have several layers of control. The lowest level is the details of the operation, the nimble finger work of sewing or playing the piano, the nimble mental work of arithmetic. Higher levels of control affect the overall task, the direction in which the work is going. Here we determine, supervise, and control the overall structure and goals. Automation can work at any level. Sometimes we really want to maintain control at the lower level. For some of us, it is the nimble execution of the finger or mind that matters. Some of us want to play music with skill. Or we like the feel of tools against wood. Or we enjoy wielding a paintbrush. In cases like these, we would not want automation to interfere. At other times we want to concentrate on higher level things. Perhaps our goal is to listen to music, and we find the radio more effective for us than the piano; perhaps our artistic skill can’t get us as far as can a computer program.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3602-3605的标注 | 添加于 2015年3月16日星期一 下午3:26:33

In making things visible, it is important to make the correct things visible. Otherwise people form explanations for the things they can see, explanations that are likely to be false. And then they find some reason for poor performance—in this example, that the remote was not very powerful. People are very good at forming explanations, at creating mental models. It is the designer’s task to make sure that they form the correct interpretations, the correct mental models: the system image plays the key role.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3646-3648的标注 | 添加于 2015年3月16日星期一 下午3:40:22

Remember, standardization is essential only when all the necessary information cannot be placed in the world or when natural mappings cannot be exploited. The role of training and practice is to make the mappings and required actions more available to the user, overcoming any shortcomings in the design, minimizing the need for planning and problem solving.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3656-3658的标注 | 添加于 2015年3月16日星期一 下午3:48:13

If we examine the history of advances in all technological fields, we see that some improvements naturally come through technology, others come through standardization. The early history of the automobile is a good example.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3666-3670的标注 | 添加于 2015年3月16日星期一 下午3:53:39

Today’s computers are still poorly designed, at least from the user’s point of view. But one problem is simply that the technology is still very primitive—like the 1906 auto—and there is no standardization. Standardization is the solution of last resort, an admission that we cannot solve the problems in any other way. So we must at least all agree to a common solution. When we have standardization of our keyboard layouts, our input and output formats, our operating systems, our text editors and word processors, and the basic means of operating any program, then suddenly we will have a major breakthrough in usability.4

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Design of Everyday Things (Norman, Don)

- 您在位置 #3671-3678的标注 | 添加于 2015年3月16日星期一 下午3:54:54

Standardize and you simplify lives: everyone learns the system only once. But don’t standardize too soon; you may be locked into a primitive technology, or you may have introduced rules that turn out to be grossly inefficient, even error-inducing. Standardize too late and there may already be so many ways of doing the task that no international standard can be agreed on; if there is agreement on an old-fashioned technology, it may be too expensive to change. The metric system is a good example: it is a far simpler and more usable scheme for representing distance, weight, volume, and temperature than the older, British system (feet, pounds, seconds, degrees on the Fahrenheit scale). But industrial nations with a heavy commitment to the old measurement standards claim they cannot afford the massive costs and confusion of conversion. So we are stuck with two standards, at least for a few more decades.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3726-3736的标注 | 添加于 2015年3月16日星期一 下午4:14:49

Many things need to be designed for a certain lack of understandability or usability. The rules of design are equally important to know here, however, for two reasons. First, even deliberately difficult designs shouldn’t be entirely difficult. Usually there is one difficult part, designed to keep unauthorized people from using the device; the rest of it should follow the normal good principles of design. Second, even if your job is to make something difficult to do, you need to know how to go about doing it. In this case, the rules are useful, for they state in reverse just how to go about the task. You systematically violate the rules. • Hide critical components: make things invisible. • Use unnatural mappings for the execution side of the action cycle, so that the relationship of the controls to the things being controlled is inappropriate or haphazard. • Make the actions physically difficult to do. require precise timing and physical manipulation. • Do not give any feedback. • Use unnatural mappings for the evaluation side of the action cycle, so that system state is difficult to interpret.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3736 的笔记 | 添加于 2015年3月16日星期一 下午4:17:23

Egyptology, trap

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Design of Everyday Things (Norman, Don)

- 您在位置 #3746-3755的标注 | 添加于 2015年3月16日星期一 下午4:22:13

One of my students worked for a computer game company helping develop a new Dungeons and Dragons game. He and his fellow students used his experience to do a class project on the difficulty of games. In particular, they combined some research on what makes games interesting with the analysis of the seven stages of action (chapter 2) to determine what factors cause difficulties in dungeon games. 6 As you might imagine, making things difficult is a tricky business. If a game isn’t difficult enough, experienced players lose interest. On the other hand, if it is too difficult, the initial enjoyment gives way to frustration. In fact, several psychological factors hang in a delicate balance: challenge, enjoyment, frustration, and curiosity. As the students reported, “Once the curiosity is lost and the frustration level becomes too high, it is hard to get a person’s interest to return to the game.” All this has to be considered, yet the game must maintain its appeal for players of many different levels, from first-time players to experienced players. One approach is to sprinkle the game with many different challenges of variable difficulty. Another is to have many little things continually happening, maintaining the curiosity motive.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3762-3768的标注 | 添加于 2015年3月16日星期一 下午4:26:53

Early in POET I examined the modern office telephone, simple looking but hard to use. I contrasted this with an automobile dashboard that has more than a hundred controls, complicated looking but easy to use. Apparent complexity and actual complexity are not at all the same. Consider a surfboard, ice skates, parallel bars, or a bugle. All are simple looking. Yet years of study and practice are required to be good at using any of these objects. The problem is that each of the apparently simple devices is capable of a wide repertoire of actions, but because there are few controls (and no moving parts), the rich complexity of action can be accomplished only through a rich complexity of execution by the user.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3775-3777的标注 | 添加于 2015年3月16日星期一 下午4:28:15

How many controls does a device need？ The fewer the controls, the easier it looks to use and the easier it is to find the relevant controls. As the number of controls increases, specific controls can be tailored for specific functions. The device may look more and more complex, but it will be easier to use.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3771-3774的标注 | 添加于 2015年3月16日星期一 下午4:28:43

Actually, increasing the number of controls can both enhance and detract from ease of use. The more controls, the more complex things look and the more the user must learn about; it becomes harder to find the appropriate control at the appropriate time. On the other hand, as the number of controls increases up to the number of functions, there can be a better match between controls and functions, making things easier to use. So the number of controls and complexity of use is really a tradeoff between two opposing factors.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3783-3784的标注 | 添加于 2015年3月16日星期一 下午4:31:10

By using a panel on which only the relevant controls are visible, you minimize the appearance of complexity. By having a separate control for each function, you minimize complexity of use. It is possible to eat your cake and have it, too.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3813-3819的标注 | 添加于 2015年3月16日星期一 下午4:49:53

With a paper manuｓｃｒｉｐｔ, you can spread the pages upon the desk, couch, wall, or floor. Large sections of the text can be examined at one time, to be reorganized and structured. If you use only the computer, then the working area (or real estate) is limited to what shows on the screen. The conventional screens display about twenty-four lines of text. Even the largest screens now available can display no more than about two full printed pages of text. The result is that corrections tend to be made locally, on what is visible. Large-scale restructuring of the material is more difficult to do, and therefore seldom gets done. Sometimes the same text appears in different parts of the manuｓｃｒｉｐｔ, without being discovered by the writer. (To the writer, everything seems familiar.)

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Design of Everyday Things (Norman, Don)

- 您在位置 #3824-3826的标注 | 添加于 2015年3月16日星期一 下午5:01:58

It is characteristic of thought processes that attention to one aspect comes at the cost of decreased attention to others. What a technology makes easy to do will get done; what it hides, or makes difficult, may very well not get done.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3832-3832的标注 | 添加于 2015年3月16日星期一 下午5:19:04

linear sequence,

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Design of Everyday Things (Norman, Don)

- 您在位置 #3826-3835的标注 | 添加于 2015年3月16日星期一 下午5:19:19

The next step in writing technology is already visible on the horizon: hypertext.9 Here we have another set of possibilities, another set of difficulties, in this case for both writer and reader. Writers frequently complain that the material they are trying to explain is complex, multidimensional. The ideas are all interconnected, and there is no single sequence of words to convey them properly. Moreover, readers vary enormously in skill, interest, and prior knowledge. Some need expansion of the most elementary ideas, some want more technical details.10 Some wish to focus on one set of topics, others find those uninteresting. How on earth can a single document satisfy them all, especially when that document must be in a linear sequence, words following words, chapters following chapters？ It has always been considered part of the skill of a writer to be able to take otherwise chaotic material and order it appropriately for the reader. Hypertext relieves the author of this burden. In theory, it also frees the reader from the constraints of the linear order; the reader can pursue the material in whatever order seems most relevant or interesting.

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Design of Everyday Things (Norman, Don)

- 您在位置 #3835-3838的标注 | 添加于 2015年3月16日星期一 下午5:30:06

Hypertext makes a virtue out of lack of organization, allowing ideas and thoughts to be juxtaposed at will. The writer throws out the ideas, attaching them to the page where they seem first relevant. The reader can take any path at all through the book. See an interesting word on the page, point at it, and the word expands into text. See a word you don’t understand, and a touch gives the definition. Who could be against such a wonderful idea？

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Design of Everyday Things (Norman, Don)

- 您在位置 #3846-3849的标注 | 添加于 2015年3月16日星期一 下午5:33:37

A footnote is essentially a signal that some comment is available to the reader. In hypertext, actual numbered footnotes will not be needed, but some sort of signal is still required. With hypertext, the signal that more information is available can be given through color, motion (such as flashing), or typeface. Touch the special word and the material appears; you don’t need a number.

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