1 L Oct-28-05 SMD157, Understanding Users Overview Case studies - - PDF document

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Oct-28-05 SMD157, Understanding Users 1 L

INSTITUTIONEN FÖR SYSTEMTEKNIK

Understanding Users

SMD157 Human-Computer Interaction Fall 2005

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Overview

• Case studies
• 47 fun-filled days of e-shopping
• Airline web sites
• Cognitive psychology revisited
• Mental Models
• How Interfaces Affect Users
• Anthropomorphism

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INSTITUTIONEN FÖR SYSTEMTEKNIK

Case Studies

47 Fun-Filled Days of E-Shopping Airline Web Sites

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One User’s Experience Ordering from an Electronic Shop

• Goal: to buy a special kind of wrench
• Day 1
• Navigating the twisty little passages to order
• Changing the quantity to 2, computer says 1, must select item

twice

• Out-of-stock ⇒ backorder ⇒ not possible, can’t leave it in

the cart ⇒ selects e-mail when in stock

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The Saga Continues

• Day 13
• Back in stock ⇒ Out-of-stock, advisory on immediate order

⇒ e-mail

• Day 22
• Back in stock ⇒ successful order
• Day 24
• Problem w/order ⇒ credit card address information incorrect
• Human intervention, customer services promises manual
• rdering

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And Continues

• Day 26
• Human intervention, FAILED, order cancelled
• Out-of-stock ⇒ e-mail
• Day 27
• Back in stock ⇒ different credit card
• Problem again, doesn’t read message, calls customer service
• Secret override method to ship, order something that requires

installation (trash compactor) ⇒ handle manually ⇒ delete the installable item

• Callback on real problem

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Still Continuing

• Day 28
• Order confirmation, but …
• Human intervention, password change
• Shipped, 2 special wrenches, 1 trash compactor
• Human intervention, fails
• Check with shipper ⇒ order already in Ohio
• Day 30
• Detailed instructions about installing the trash compactor

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Finally the End

• Day 32
• Finally the wrenches, and the trash compactor
• Day 40
• Arranging return of the trash compactor
• Day 46
• Second notice of unsuccessful pickup attempt
• Day 47
• The last of the trash compactor

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Analysis

• Lack of understanding of the user
• Difficult navigation
• Password problem
• Clear lack of basic understanding of retailing
• Ordering 2
• Out-of-stock/backorder
• Artificial walls
• Lack of a ship function
• The secret override
• Inability to update system
• 2 years of experience
• Relying on the adaptability of humans

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Not an Isolated Instance

• Airline ticketing systems on the web
• User goal:
• Luleå to
• Brno via Prague or Vienna
• On to Las Vegas
• Return to Luleå

Luleå Prague

• r

Vienna Las Vegas Brno

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Airline 1, SAS

Luleå Stockholm Vienna Chicago Copenhagen Brno User goal Vegas Prague

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Airline 2, Austrian

Luleå Stockholm Dulles Brno Zurich User goal Vegas Vienna

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Problems

• SAS
• Goal not directly supported
• Premature commitment on 2 round trips
• More segments lower the cost
• Austrian
• Goal not directly supported
• Premature commitment on 2 round trips
• Bait-and-switch

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INSTITUTIONEN FÖR SYSTEMTEKNIK

Cognitive Psychology Revisited

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Why Do We Need Cognitive Psychology?

• Interacting with technology is cognitive
• Helps us to understand users
• Cognitive psychology can
• Identify and explain the nature and causes of problems users

encounter

• Explain cognitive processes involved and cognitive limitations
• f users
• Provide knowledge about what users can and cannot be

expected to do

• Supply theories, modeling tools, guidance and methods to

improve the design of interactive products

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Core Cognitive Aspects

• Attention
• Perception and recognition
• Memory
• Reading, speaking and listening
• Problem-solving, planning, reasoning and decision-

making, learning

• Here we focus on attention, perception & recognition, &

memory

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Attention

• Selecting what to concentrate on
• Focused attention enables:
• Selection in terms of competing stimuli, but
• Limits our ability to keep track of all events
• Information at the interface should be structured to

capture users’ attention

• use perceptual boundaries (windows),
• color,
• reverse video,
• sound and flashing lights

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Design Implications for Attention

• Make information salient when it needs attention, with things that

make it stand out like:

• color,
• rdering,
• spacing,
• underlining,
• sequencing and animation
• Avoid cluttering the interface
• Follow the google.com example of crisp, simple design
• Avoid using too much just because the software allows it

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An Example of the Over-Use of Graphics

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Perception and Recognition

• How information is acquired from the world and

transformed into experiences

• Obvious implication is to design representations that

are readily perceivable, e.g.

• Text should be legible
• Icons should be easy to distinguish and read

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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?

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Memory

• Involves encoding and recalling knowledge and acting

appropriately

• We don’t remember everything
• Involves filtering and processing
• Context is important in affecting our memory
• We recognize things much better than being able to

recall things

• The rise of the GUI over command-based interfaces
• Better at remembering images than words
• The use of icons rather than names

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Memory Types and Limits

• Sensory memory is very limited.
• Auditory memory, 2 second duration
• Visual memory, .5 second duration
• Short term or working memory
• 7 ± 2 chunks, several second duration
• 1-2 things
• Long term memory
• Essentially unlimited, but you have to find things.

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The Problem with the Classic “7±2”

• George Miller’s theory says people can keep 7±2

chunks in their short-term (verbal) memory

• Many designers have been led to believe that this is

useful finding for interaction design

• 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, …
• But this is wrong? Why?

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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
• nly briefly heard or seen them
• Sometimes a small number of items is good design
• But it depends on task and available screen space

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Appropriate Application of Memory Research, File Management

• A real problem to most users
• Memory involves 2 processes
• Recall-directed, association, incomplete recall
• Recognition-based, scanning
• Design to optimize both kinds of memory processes
• Facilitate existing memory strategies and try to assist

users when they get stuck

• Help users encode files in richer ways
• Provide them with ways of saving files using color, flagging,

image, flexible text, time stamping, etc

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External Cognition

• Concerned with explaining how we interact with external

representations (e.g. maps, notes, diagrams)

• What are the cognitive benefits and what processes

involved

• How they extend our cognition
• What computer-based representations can we develop

to help even more?

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Externalizing to Reduce Memory Load

• Diaries, reminders, calendars, notes, shopping lists, to-

do lists - written to remind us of what to do

• Post-its, piles, marked emails - where placed indicates

priority of what to do

• External representations:
• Remind us that we need to do something (e.g. to buy

something for mother’s day)

• Remind us of what to do (e.g. buy a card)
• Remind us when to do something (e.g. send a card by a

certain date)

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Computational Offloading

• When a tool is used in conjunction with an external

representation to carry out a computation (e.g. pen and paper)

• Try doing the two sums below (a) in your head, (b) on a

piece of paper and (c) with a calculator.

• 234 + 456 =??
• CCXXXIV + CCCCLVI = ???
• Which is easiest and why? Both are identical sums

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Annotation and Cognitive Tracing

• Annotation involves modifying existing representations

through making marks

• e.g. crossing off, ticking, underlining
• Cognitive tracing involves externally manipulating items

into different orders or structures

• e.g. playing scrabble, playing cards

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Design Implications

• Provide external representations at the interface that

reduce memory load and facilitate computational

• ffloading

e.g., Information visualizations have been designed to allow people to make sense and rapid decisions about masses

• f data

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INSTITUTIONEN FÖR SYSTEMTEKNIK

Mental Models

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Mental Models

• Users develop an understanding of a system through

learning & using it

• This is often called a mental model
• How to use the system
• How the system works
• People make inferences using mental models of how to

carry out tasks

• Used to predict results of non-rote actions
• Used to correct problems

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Difference Between Conceptual Models and Mental Models

• Conceptual models are the designers idea of how the

users will perceive the interface

• It’s a property of the interface
• Mental models are people’s idea of how something
• perates
• It’s in the user’s head

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Examples of Mental Models

• Naïve physics
• Do heavy objects fall faster than light objects?
• Household thermostat and furnace
• Warming a house to 22, will it go faster if the thermostat is set

higher?

• Macintosh trash can (metaphor)

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Mental Models & System Design

• Notion of mental models has been used as a basis for

conceptual models

• Assumption is that if you can understand how people

develop mental models then can help them develop more appropriate mental models of system functionality

• For example, a design principle is to try to make

systems transparent so people can understand them better and know what to do

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INSTITUTIONEN FÖR SYSTEMTEKNIK

How Interfaces Affect Users

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Overview

• Expressive interfaces
• how the ‘appearance’ of an interface can elicit positive

responses

• Negative aspects
• how computers frustrate users

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Expressive Interfaces

• Color, icons, sounds, graphical elements and animations are used to

make the ‘look and feel’ of an interface appealing

• Conveys an emotional state!
• In turn this can affect the usability of an interface
• People are prepared to put up with certain aspects of an interface

(e.g. slow download rate)

• If the end result is very appealing and aesthetic

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Friendly Interfaces

• Microsoft pioneered friendly interfaces for

technophobes - ‘At home with Bob’ software

• 3D metaphors based on familiar places (e.g. living

rooms)

• Agents in the guise of pets (e.g. bunny, dog) were

included to talk to the user

• Make users feel more at ease and comfortable

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User Frustration, Many Causes

• When an application doesn’t work properly or crashes
• When a system doesn’t do what the user wants it to do
• When a user’s expectations are not met
• When a system does not provide sufficient information

to enable the user to know what to do

• When error messages pop up that are vague, obtuse or

condemning

• When the appearance of an interface is garish, noisy,

gimmicky or patronizing

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Error Messages “The application, Word Wonder, has unexpectedly quit due to a type 2 error.” Why not instead: “The application , Word Wonder, has expectedly quit due to poor coding in the

• perating system”

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Shneiderman’s Guidelines for Error Messages

• Avoid using terms like FATAL, INVALID, BAD
• Audio warnings should be user configurable
• Many find them embarrassing or annoying
• Avoid UPPERCASE and long code numbers
• Messages should be precise rather than vague
• Provide context-sensitive help

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Website Error Message…

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More Helpful Error Message

“The requested page /helpme is not available on the web server. If you followed a link or bookmark to get to this page, please let us know, so that we can fix the problem. Please include the URL of the referring page as well as the URL of the missing page. Otherwise check that you have typed the address of the web page correctly.

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INSTITUTIONEN FÖR SYSTEMTEKNIK

Anthropomorphism

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Anthropomorphism

• Attributing human-like qualities to inanimate objects

(e.g. cars, computers)

• Well known phenomenon in advertising
• Dancing butter, drinks, breakfast cereals
• Exploited in human-computer interaction to:
• Make user experience more enjoyable
• Increase motivation
• Make people feel at ease
• Reduce anxiety

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Which Do You Prefer?

• As a welcome message
• Hello Chris! Nice to see you again. Welcome back. Now what were we

doing last time? Oh yes, exercise 5. Let’s start again.

• User 24, commence exercise 5.
• Feedback when get something wrong
• Now Chris, that’s not right. You can do better than that.Try again.
• Incorrect. Try again.
• Is there a difference as to what you prefer depending on type of

message? Why?

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About Anthropomorphism

• Support
• Educational programs that flatter and praise have positive

impact on users.

• Criticisms
• Deceptive, make people feel anxious, inferior or stupid
• Many prefer the more impersonal
• Personalized feedback is considered to be less honest and

makes users feel less responsible for their actions

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Virtual Characters

• Increasingly appearing on our screens
• Web, characters in videogames, learning companions,

wizards, newsreaders, popstars

• Provides a persona that is welcoming, has personality

and makes user feel involved with them

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Disadvantages

• Lead people into false sense of belief, enticing them to

confide personal secrets with chatterbots (e.g. Alice)

• Annoying and frustrating
• E.g. Clippy
• Not trustworthy
• virtual e-commerce assistants?

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Virtual Characters: Agents

• Classified by the degree of anthropomorphism:
• Synthetic characters

+ autonomous, able to respond to external events

• Animated agents

+ Play a collaborative role at the interface + Often cartoon-like

• Emotional agents

+ Pre-defined personality and emotions, user can change

• Embodied conversational agents

+ Human-like body + Uses gesture, non-verbal communication (facial expressions, winks) while talking + Sophisticated AI techniques

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Summary

• Problems with e-shopping
• Think about the users and what they want to do
• Cognitive psychology revisited
• Attention, perception, and memory are critical
• Externalizing helps reduce memory load
• Mental Models
• User’s idea of how things work
• How Interfaces Affect Users
• Positive and negative
• Anthropomorphism
• Attributing human-like characteristics to interfaces

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Questions?