3
Hall of Shame
Page setup for printing in IE5
Problems codes for header & footer
information recognition over recall! no equivalent GUI help is the way to find out,
but not obvious how
4
Introduction
Science Finds,Industry Applies,Man Conforms.
[Motto of the 1933 Chicago World’s Fair]
People Propose,Science Studies,Technology Conforms.
[Don Norman’s person-centered motto for the next century]
5
Design
“It’s easy to make things hard. It’s hard to make things easy.” User interface is a creative process Designers have difficulty thinking like users
Can’t ‘unlearn’ something e.g. need for Save button
7
Why is Design Hard?Over the last century... the number of things to control has increased dramatically
car radio: AM, FM1, FM2, 5 pre-sets, station selection, balance, fader, bass,
treble, distance, mono/stereo, dolby, tape eject, fast forward and reverse, etc (while driving at night!)
display is increasingly artificial red lights in car indicate problems vs flames for fire
feedback more complex, subtle, and less natural is your digital watch alarm on and set correctly?
errors increasing serious and/or costly airplane crashes, losing days of work...
8
Lack of user discovery
Specifications are always wrong: “Only slightly more than 30% of the code
developed in application software development ever gets used as intended by end-users. The reason for this statistic may be a result of developers not understanding what their users need.”
Hugh Beyer and Karen Holtzblatt, “Contextual Design: A Customer-Centric Approach to Systems Design”,
ACM Interactions, Sep+Oct, 1997, iv.5, p. 62.
Need for prototyping and iteration
9
Why is Design Hard? (contd.)
Marketplace pressures adding functionality (complexity) now easy and
cheap computers
adding controls/feedback expensive physical buttons on calculator, microwave oven widgets consume screen real estate
design usually requires several iterations before success product pulled if not immediately successful
10
Why is Design Hard? (contd.)
People often consider cost and appearance over human factors design bad design not always visible people tend to blame themselves when errors occur
“I was never very good with machines” “I knew I should have read the manual!” “Look at what I did! Do I feel stupid!”
E.g. the new wave of cheap telephones: accidentally hangs up when button hit with chin bad audio feedback cheap pushbuttons — mis-dials common trendy designs that are uncomfortable to hold hangs up when dropped functionality that can’t be accessed (redial, mute, hold)
11
More issues with UI difficulties
Tasks and domains are complex MacDraw 1 (20cmd) vs. Illustrator Word 1 vs. Office XP (Word XP has 1000)
Existing theories and guidelines are not sufficient Too specific and/or too general Standard does not address all issues.
Adding graphics can make worse Pretty Easy to use
Can’t just copy other designs Legal issues
12
Differing Perspectives System (Programmer) Centred Design
What can be built easily on this platform? What can I create from the tools available? What do I as a developer find interesting to work on?
User Centred Design Design based upon user’s
abilities and needs context work tasks
13
What is Design?
Design is conscious Systematic principles and methods available Though, no effective rationalized generative
theories Still pervaded by intuition, tacit knowledge, and
gut reaction.
14
What is Design? (contd.)
Design keeps human concerns in the center creative solutions in a space of alternatives that is
shaped by competing values and resource needs, though rarely quantifiable
adherence to ‘Threshold of indignation’ for different classes of user
multidimensional understanding of what concerns users is critical to an understanding
15
What is Design? (contd.)
Design is a dialog with materials Iterative at two levels
Designer iterates prototypes User community recognise new potentials
Carroll's ‘Task-Artefact Cycle’
New technologies bring with them new domains for design Stone building brought architecture Printing brought graphic design Word processing brought DTP
16
What is Design? (contd.)
Design is creative Cannot be prescribed or rationalised It begins with finding the problems
Envisioning the needs that people have but do not recognise
Design is communication Couched in a background of shared design
language in the user community
17
What is Design? (contd.)
Design has social consequences social and political dimensions an explicit part of
the analysis and of the design dialog Participatory Design
Design is a social activity designer both facilitated and constrained by
interactions with other people and the organisation
18
What is User-centered Design?
Design FROM THE USER’S PERSPECTIVE user and customer not the same person
don’t design for managers work process Developers work WITH target users
help define what the system will do and how lots of iterative exploration and feedback from users maintain direct contact with real users
Understanding work process points where humans and computers intersect
Not technology-centered/feature driven
20
A counter example in capturing attention in the user interface.
What happened to the Apollo 13 screens during the Oxygen Tank 2 explosion.
29
Data vs. Information
Data becomes information when shown in context to reference values (limits, past information, correlated data, what’s expected, etc.)
What is 800? Is it good or bad? Depends on the limits, and the scale, and our goals.
30
User-Centered Design Golden Rule: KNOW THE USER
Attributes physical & cognitive abilities
memory (retention and recall) cultural/ethnic issues
experiential Organizational / job abilities Users become a part of the design process
Involve users throughout project Difference from programming (debugging)
31
Seven Principles for User-Centred Design1. Use both knowledge in the world and
knowledge in the head.2. Simplify the structure of tasks.
provide mental aids use technology to make visible what would
otherwise be invisible automate but keep the task much the same change the nature of the task
3. Make things visible. Bridge the gulfs of Execution and Evaluation
32
Seven Principles for User-Centred Design4. Get the mappings right.
Exploit natural mappings Make sure that the user can determine the
relationships: between intentions and possible actions, between actions and their effects on the system, between actual system state and what is perceivable by sight/sound/feel, between the perceived system state and the needs, intentions and expectations of the users
5. Exploit the power of constraints Both natural and artificial
33
Seven Principles for User-Centred Design6. Design for error.
(Murphy's always there!)
7. When all else fails, standardise Any standard need only be learned once Standards only when all the necessary
information cannot be placed in the world or when natural mappings cannot be exploited
Design a thing by considering it in its next larger context
34
Simple Rules ofUser Interface Designs
Cognitive Engineering Principles based on psychology of user Don Norman’s Principles
Although users are distinct individuals they have similar architectures Learning and memory for items is similar Motor, visual and hearing performance is
similar
35
Some Basic Human Characteristics
Humans like to problem solve Humans don’t like insoluble problems Humans are always learning Learning is hard Humans use prior learning to support new
leaning Users don’t read manuals but work by copying
and asking Users are always building models of their world
36
Applying Psychology to Design
Use existing knowledge where possible Assist learning by using metaphor
User recognition over recall E.g. menu items
Don’t overload short-term memory Limit the need to remember information between screens,
by maintaining an external memory, e.g. of current settings
Design for consistency to avoid interference Retroactive and proactive
37
Applying Psychology to Design
Make use of human hardware E.g. colour vision
Use a variety of modalities E.g. vision and audio
Compensate for difficult tasks E.g. pop-up menus to avoid eye movement
Avoid anomalies E.g. unwanted after effects
38
The User as an Intelligent “Muddler”
Users don’t mind if something doesn’t make sense they build their own model to make it make
sense Users prefer simple models Inconsistency doesn’t bother a user
A simple model which doesn’t always match is better than a perfect complex model that is too hard to learn
39
What happens when you cancel a cancelled operation?
Do I have any choice in this?
Umm, thanks for the warning,but what should I do?
Uhhh… I give up on this one
43
Usability Truths1. Your best guess is not good enough
2. The user is always right
3. The user is not always right
4. Users are not designers
5. Designers are not users
6. Vice presidents are not users
7. Less is More
8. Details matter
9. Help doesn’t
10. Usability Engineering is Process
(Drawn from J. Nielsen, Usability Engineering )
44
Alternative UI Attributes Invisible Minimal training required (easy to learn) High transfer of training (easy to remember) Predictability Few errors Easy to recover from errors People perform real tasks well (efficient) It is flexible It is intelligent People like it (subjectively pleasing)
… and many others“It is easy to make things hard. It is hard to make things easy.”
A. Chapanis, 1982
45
Design Approaches
Guidelines and Standards Discount Usability Engineering (Nielsen) Norman’s Action Cycle Model (1988)
46
Design Guidelines…
Apply at multiple levels of design Often become obvious to users of poorly
designed interfaces Are easy to ignore when deadlines approach Are neither complete nor orthogonal Have psychological underpinnings (hopefully)
47
Discount Usability Engineering (Nielsen)
“Le mieux est l’ennemi du bien” (Voltaire 1764)
Discount Usability Technique1 (Nielsen) User and task observation Scenarios Simplified thinking aloud Heuristic Evaluation
Management Issues Recognise the need for usability Give usability management support Devote & ring-fence resources Integrate systematic usability engineering activities Subject all user interfaces to user testing
Evolution of UE Acceptance Skepticism stage Curiosity Stage Partnership Stage Acceptance Stage
1 www.useit.com/papers/guerilla_hci.html
48
Norman’s Action Cycle Model (1988)
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
51
Bridges
Physical System Goals
Interface Mechanism
Action Specification
Intentions
Interface Display
Interpretation
Evaluation
52
Gulfs of Execution and Evaluation
Gulf of Execution Differences between what user wants to do
and controls available E.g. filling a bath tub
Gulf of Evaluation Reflects user effort to compare known goal
with state of system. E.g. A-320 flight-path display feedback
53
Evaluation & Design Questions Execution
Can the user tell what actions are possible? Does the interface help with mapping from intention to
physical movement? Does the device easily support required actions?
Evaluation Can the user tell if the system is in the desired state? Can the user map from the system state to an
interpretation? Can the user tell what state the system is in?
56
Usability Principles
Physical System Goals
Visibility
Good Conceptual Model
Good Mappings
Feedback
Affordances
57
Factors in HCI
Exercise: What happens when a new computing system is introduced?
Case study – Library automation
OrganizationalFactors
EnvironmentalFactors
Health & Safety
Cognition andEmotion
ComfortFactors
User Interface Task Factors
Constraints System FunctionalityProductivity
Factors
58
The Waterfall Model ofSoftware Design
Requirements Analysis and Definition
System and Software Design
Implementation and Unit Testing
Integration and System Testing
60
The “Star” Life Cycle
Evaluation
ImplementationTask analysis/
Functional analysis
Requirementsspecification
Conceptual design/Formal design
Prototyping
Hix & Hartson (1989) Towards empirically derived methodologies and tools for human-computer interface development. International Journal of Man-Machine Studies, 31, 477-494