Chapter 3: Understanding users 了解使用者

What is cognition ? 何謂認知？ 當我們進行每日的例行事物時，「認知」就會在我們的腦海中進行運作，這就是所謂的「認知程序」。

What is cognition ? 何謂認知？ 認知有許多不同的類型，Norman(1993) 將認知區分為「體驗的認知」experimental cognition 以及 「反思的認知」reflective cognition. experimental cognition: 我們對週遭事物進行有效率的接收、行動及反應的程序。E.g. drive a car, read a book and having a conversation. reflective cognition: 思考 比較與決策一些事物。E.g. designing, learning and writing a book.

cognitive processes 認知的特定程序 Attention 注意力 Perception and recognition 知覺及辨識 Memory 記憶 Learning 學習 Reading, speaking and listening 讀、說、聽 Problem-solving, planning, reasoning and decision-making 解決問題、進行計畫、解釋道 理、作決策

cognitive processes 認知的特定程序 這些認知程序是會互相依存的，而且某些會和某 種特定的活動有關。 E.g.你要準備一項考試，你必須要先注意到和這 個考試的相關題材，加以閱讀、思索然後記憶， 這就是認知的一個程序。

Attention 注意力 在一個特定的範圍或是時間點，對某些事物加以選擇性 專注的程序 Selecting things to concentrate on at a point in time from the mass of stimuli around us Involves auditory and/or visual senses E.g. auditory attention : waiting in the dentist’s waiting room for our name to be called. E.g. visual attention: scanning the basketballs results in a newspaper. 在一個特定的範圍或是時間點，對某些事物加以選擇性 專注的程序

Attention 注意力 注意力使我們注意到與所進行的事情相關的資訊，而這個程序進行的難易程度，有賴於： (a) our goals 我們是否有明確的目的 (b) information presentation 我們所需要的資訊在其環境中是否清楚的 呈現

Attention 注意力 (a) our goals:我們有明確的目的時 If we know what we want to find out we try to match this with the information that is available. e.g. Buying printer in the Internet. Extending the research topics from your previous tutors. 我們沒有明確的目的時 When we are not sure exactly what we are looking for may browse through information, allowing it to guide our attention to interesting items. e.g. When we go to a restaurant we may have an idea of eating, but we do not know what we want to order.

Attention 注意力 (b) Information presentation 資訊的呈現會影響使用者注意力程序的難易度

Activity: Find the price of a double room at the Holiday Inn in Bradley

Activity: Find the price for a double room at the Quality Inn in Columbia

Activity Tullis (1987) found that the two screens produced quite different results 1st screen - took an average of 5.5 seconds to search 2nd screen - took 3.2 seconds to search Why, since both displays have the same density of information 資訊密度(31%)? Spacing In the 1st screen the information is bunched up together, making it hard to search In the 2nd screen the characters are grouped into vertical categories of information making it easier

Design implications for attention Make information salient 突出 when it needs attending to Use techniques that make things stand out like colour, ordering, spacing, underlining, sequencing 順序排列 and animation Avoid cluttering 雜亂the interface - follow the google.com example of simple design Avoid using too much because the software allows it

An example of over-use of graphics

Perception and recognition 知覺及辨識 How information is acquired from the world, via the different sense organs, e.g. eyes, ears, fingers and transformed into experiences of objects, events, sounds, and tastes (Roth, 1986) 人們對於知覺的效應 Vision > Hearing > Touch 資訊如何從環境中被取得，經由不同的感官(如眼、耳、手)並轉化為物體、事件、聲音及味道相關的經驗

Perception and recognition 知覺及辨識 Obvious implication is to design representations that are readily perceivable, e.g. Text should be legible Icons should be easy to distinguish and read

Is colour contrast good? Bett

Are borders and white space better?

Activity Weller (2004) found people took less time to locate items for information that was grouped using a border (2nd screen) compared with using color contrast (1st screen) Some argue that too much white space on web pages is detrimental 有害的 to search Makes it hard to find information Do you agree?

Which is easiest to read and why? What is the time? What is the time? What is the time? What is the time? What is the time?

Which is easiest to read and why? What is the time? 在一般印刷品上 What is the time? 在一般標誌上

交通警告標誌 根據設計的複雜程度，大約五種顏色是人們能接受的數量 (Universal Principles of Design, p.38)

Design implications Book translation Advance editing Representations of information need to be designed to be perceptible and recognizable: Icons and other graphical representations should enable users to readily distinguish their meaning Sounds should be audible and distinguishable (小綠人的登登登) Speech output should enable users to distinguish between the set of spoken words (國珍老師的研究) Text should be legible and distinguishable from the background Bordering and spacing are effective visual ways of grouping information Advance editing Book translation

Memory 記憶 記憶提供我們許多不同種類的知識，已使我們 採取適當的行動 We don’t remember everything – 我們會使用一種過濾的程序(filtering process)， 決定哪一些資訊要被處理與記憶，但是這個過濾的 程序並非沒有問題。(記住不該記的….) Context is important in affecting our memory (i.e., where, when)

Activity Memory : words 兩個人在游泳池中 紅色的牆面 木造的模型房子 木造餐具在杯中

Memory : Pictures

Memory 記憶 Well known fact that we recognize 辨識 things much better than being able to recall 回憶 things Better at remembering images than words Why interfaces are largely visual

Processing in memory 記憶的程序 編碼 Encoding is first stage of memory 編碼決定處理環境中的何種資訊，且這些資訊如何被大腦 解讀？其後，編碼動作執行的程度，會影響到我們回憶起 這個資訊的能力 The more attention paid to something, and the more it is processed in terms of thinking about it and comparing it with other knowledge, the more likely it is to be remembered e.g., when learning about HCI, it is much better to reflect upon it, carry out exercises, have discussions with others about it, and write notes than just passively read a book, listen to a lecture or watch a video about it

Context 場景是如何被喚起記憶的因素 Context affects the extent to which information can be subsequently retrieved 場景是如何被喚起記憶的因素

Context information that was encoded in a different context e.g., You are on a train and someone comes up to you and says hello. You don’t recognize him for a few moments but then realize it is one of your neighbors. You are only used to seeing your neighbor in the hallway of your apartment block and seeing him out of context makes him difficult to recognize initially

大頭兵

Activity Try to remember the dates of your grandparents’ birthday Try to remember the cover of the last two CDs you listen Which was easiest? Why?

Activity Comments People are very good at remembering visual cues about things e.g., the colour of items, the location of objects and marks on an object They find it more difficult to learn and remember arbitrary material e.g., birthdays and phone numbers

Recognition辨識 versus recall 回憶 Command-based interfaces require users to recall from memory a name from a possible set of 100s GUIs provide visually-based options that users need only browse through until they recognize one Web browsers, MP3 players, etc., provide lists of visited URLs, song titles etc., that support recognition memory

The problem with the classic ‘72’ George Miller’s theory of how much information people can remember People’s immediate memory capacity is very limited Many designers have been led to believe that this is useful finding for interaction design

What some designers get up to… Present only 7 options on a menu Display only 7 icons on a tool bar Have no more than 7 bullets in a list Place only 7 items on a pull down menu Place only 7 tabs on the top of a website page But this is wrong? Why?

Why? Inappropriate application of the theory People can scan lists of bullets, tabs, menu items till they see the one they want They don’t have to recall them from memory having only briefly heard or seen them Sometimes a small number of items is good design But it depends on task and available screen estate

Personal information management 你們是如何記住你的信用卡、金融卡的卡號？ E-mail address的密碼、PC home, Amazon的密碼？ 其他的密碼？

Personal information management (PIM) is a growing problem for most users Who have vast numbers of documents, images, music files, video clips, emails, attachments, bookmarks, etc., Major problem is deciding where and how to save them all, then remembering what they were called and where to find them again Naming most common means of encoding them (what is your pet’s name?最常用的提示語) Trying to remember a name of a file created some time back can be very difficult, especially when have 1000s and 1000s How might such a process be facilitated taking into account people’s memory abilities?

Personal information management Memory involves 2 processes recall-directed and recognition-based scanning recall-directed以回億所引導: 將相關的資料記憶下來，記憶的過程越精確，使用者越能成功的繼起所要尋找檔案的名稱 recognition-based scanning 以辨識為基礎的掃描 當無法記起所要尋找的檔案時，便藉著瀏覽器的 檔案目錄是著喚起記憶

Personal information management File management systems should be designed to optimize both kinds of memory processes e.g., Search box and history list

Personal information management Help users encode files in richer ways Provide them with ways of saving files using colour, image, flexible text, time stamping, etc

Design implications Don’t overload users’ memories with complicated procedures for carrying out tasks Design interfaces that promote recognition rather than recall Provide users with a variety of ways of encoding digital information to help them remember where they have stored them e.g., categories, colour, icon

Learning 學習 學習如何使用一套軟體 使用一套電腦軟體理解一個主題

Learning 學習 People find it very hard to learn by following a set of instructions in a manual They much prefer to “learn through doing” GUIs are good environments for supporting this kind of active learning

Design implications Design interfaces that encourage exploration

Design implications Dynamically link concrete representations and abstract concepts to facilitate the learning of complex material http://office.microsoft.com/training/Training.aspx?AssetID=RP061066971028&CTT=6&Origin=RC061063991028#

Assignment 摘要與心得 作業一的研究問題 Cognitive Psychology & IA: From Theory to Practice by Jason Withrow on 2003/08/11 http://www.boxesandarrows.com/view/cognitive_psychology_ia_from_theory_to_practice