1. Usability goals Effective to use (Man kan göra det man vill göra.)
Efficient to use (Bra invävnad av funktionaliteten i människans pågående aktivitet, dvs. minimalt merarbete.)
Safe to use
Have good utility (Man kan göra det man vill göra på det sätt man vill.
Easy to learn
Easy to remember how to use

2. User experience goals Satisfying - rewarding Fun - support creativity
Enjoyable - emotionally fulfilling
Entertaining …and more
Helpful
Motivating
Aesthetically pleasing

3. Usability and user experience goals
How do usability goals differ from user experience goals?
Are there trade-offs between the two kinds of goals?
e.g. can a product be both fun and safe?
How easy is it to measure usability versus user experience goals?

4. Design principles
Generalizable abstractions for thinking about different aspects of design
The do’s and don’ts of interaction design
What to provide and what not to provide at the interface
Derived from a mix of theory-based knowledge, experience and common-sense

5. Visibility • This is a control panel for an elevator.
• How does it work?
• Push a button for the floor you want?
• Nothing happens. Push any other button? Still nothing. What do you need to do?
It is not visible as to what to do!
From:

6. Visibility • make relevant parts visible
…you need to insert your room card in the slot by the buttons to get the elevator to work!
How would you make this action more visible?
• make the card reader more obvious
• provide an auditory message, that says what to do (which language?)
• provide a big label next to the card reader that flashes when someone enters
• make relevant parts visible
• make what has to be done obvious

7. Feedback Sending information back to the user about what has been done
Includes sound, highlighting, animation and combinations of these
e.g. when screen button clicked on provides sound or red highlight feedback:
“ccclichhk”

8. Constraints Restricting the possible actions that can be performed
Helps prevent user from selecting incorrect options
Three main types (Norman, 1999)
physical
cultural
logical

9. Physical constraints
Refer to the way physical objects restrict the movement of things
E.g. only one way you can insert a key into a lock
How many ways can you insert a CD or DVD disk into a computer?
How physically constraining is this action?
How does it differ from the insertion of a floppy disk into a computer?

10. Logical constraints
Exploits people’s everyday common sense reasoning about the way the world works
An example is they logical relationship between physical layout of a device and the way it works as the next slide illustrates

11. Logical or ambiguous design?
Where do you plug the mouse?
Where do you plug the keyboard?
top or bottom connector?
Do the color coded icons help?
From:

12. How to design them more logically
(i) A provides direct adjacent mapping between icon and connector
(ii) B provides color coding to associate the connectors with the labels
From:

13. Cultural constraints
Learned arbitrary conventions like red triangles for warning
Can be universal or culturally specific

14. Which are universal and which are culturally-specific?

15. Mapping
Relationship between controls and their movements and the results in the world
Why is this a poor mapping of control buttons?

16. Mapping Why is this a better mapping?
The control buttons are mapped better onto the sequence of actions of fast rewind, rewind, play and fast forward

17. Consistency
Design interfaces to have similar operations and use similar elements for similar tasks
For example:
always use ctrl key plus first initial of the command for an operation – ctrl+C, ctrl+S, ctrl+O
Main benefit is consistent interfaces are easier to learn and use

18. Affordances: to give a clue
Refers to an attribute of an object that allows people to know how to use it
e.g. a mouse button invites pushing, a door handle affords pulling
Norman (1988) used the term to discuss the design of everyday objects
Since has been much popularised in interaction design to discuss how to design interface objects
e.g. scrollbars to afford moving up and down, icons to afford clicking on

19. What does ‘affordance’ have to offer interaction design?
Interfaces are virtual and do not have affordances like physical objects
Norman argues it does not make sense to talk about interfaces in terms of ‘real’ affordances
Instead interfaces are better conceptualised as ‘perceived’ affordances
Learned conventions of arbitrary mappings between action and effect at the interface
Some mappings are better than others

20. Activity Physical affordances:
How do the following physical objects afford? Are they obvious?

21. Activity Virtual affordances
How do the following screen objects afford?
What if you were a novice user?
Would you know what to do with them?

22. Usability principles
Similar to design principles, except more prescriptive
Used mainly as the basis for evaluating systems
Provide a framework for heuristic evaluation

23. Usability principles (Nielsen 2001)
Visibility of system status
Match between system and the real world
User control and freedom
Consistency and standards
Help users recognize, diagnose and recover from errors
Error prevention
Recognition rather than recall
Flexibility and efficiency of use
Aesthetic and minimalist design
Help and documentation

24. Understanding and conceptualizing interaction

25. Recap HCI has moved beyond designing interfaces for desktop machines
About extending and supporting all manner of human activities in all manner of places
Facilitating user experiences through designing interactions
Make work effective, efficient and safer
Improve and enhance learning and training
Provide enjoyable and exciting entertainment
Enhance communication and understanding
Support new forms of creativity and expression

26. Understanding the problem space
What do you want to create?
What are your assumptions?
Will it achieve what you hope it will?

27. A framework for analysing the problem space
Are there problems with an existing product?
Why do you think there are problems?
Why do you think your proposed ideas might be useful?
How would you see people using it with their current way of doing things?
How will it support people in their activities?
Will it really help them?

28. An example
What were the assumptions made by cell phone companies when developing WAP services?
Was it a solution looking for a problem?

29. Assumptions: realistic or wish-list?
People want to be kept informed of up-to-date news wherever they are - reasonable
People want to interact with information on the move - reasonable
People are happy using a very small display and using an extremely restricted interface - not reasonable
People will be happy doing things on a cell phone that they normally do on their PCs (e.g. surf the web, read , shop, bet, play video games) - reasonable only for a very select bunch of users

30. From problem space to design space
Having a good understanding of the problem space can help inform the design space
e.g. what kind of interface, behavior, functionality to provide
But before deciding upon these it is important to develop a conceptual model

31. Conceptual model
Need to first think about how the system will appear to users (i.e. how they will understand it)
A conceptual model is a high level description of:
“the proposed system in terms of a set of integrated ideas and concepts about what it should do, behave and look like, that will be understandable by the users in the manner intended”

32. First steps in formulating a conceptual model
What will the users be doing when carrying out their tasks?
How will the system support these?
What kind of interface metaphor, if any, will be appropriate?
What kinds of interaction modes and styles to use?
Always keep in mind when making design decisions how the user will understand the underlying conceptual model

33. Conceptual models Many kinds and ways of classifying them
Here we describe them in terms of core activities and objects
Also in terms of interface metaphors

34. Conceptual models based on activities
Giving instructions
issuing commands using keyboard and function keys and selecting options via menus
Conversing
interacting with the system as if having a conversation
Manipulating and navigating
acting on objects and interacting with virtual objects
Exploring and browsing
finding out and learning things

35. 1. Giving instructions
Where users instruct the system and tell it what to do
e.g. tell the time, print a file, save a file
Very common conceptual model, underlying a diversity of devices and systems
e.g. CAD, word processors, VCRs, vending machines
Main benefit is that instructing supports quick and efficient interaction
good for repetitive kinds of actions performed on multiple objects

36. 2. Conversing
Underlying model of having a conversation with another human
Range from simple voice recognition menu-driven systems to more complex ‘natural language’ dialogues
Examples include timetables, search engines, advice-giving systems, help systems
Recently, much interest in having virtual agents at the interface, who converse with you, e.g. Microsoft’s Bob and Clippy

37. Pros and cons of conversational model
Allows users, especially novices and technophobes, to interact with the system in a way that is familiar
makes them feel comfortable, at ease and less scared
Misunderstandings can arise when the system does not know how to parse what the user says
e.g. child types into a search engine, that uses natural language the question:
“How many legs does a centipede have?” and the system responds:

39. 3. Manipulating and navigating
Involves dragging, selecting, opening, closing and zooming actions on virtual objects
Exploit’s users’ knowledge of how they move and manipulate in the physical world
Exemplified by (i) what you see is what you get (WYSIWYG) and (ii) the direct manipulation approach (DM)
Shneiderman (1983) coined the term DM, came from his fascination with computer games at the time

40. Core principles of DM
Continuous representation of objects and actions of interest
Physical actions and button pressing instead of issuing commands with complex syntax
Rapid reversible actions with immediate feedback on object of interest

41. Why are DM interfaces so enjoyable?
Novices can learn the basic functionality quickly
Experienced users can work extremely rapidly to carry out a wide range of tasks, even defining new functions
Intermittent users can retain operational concepts over time
Error messages rarely needed
Users can immediately see if their actions are furthering their goals and if not do something else
Users experience less anxiety
Users gain confidence and mastery and feel in control

42. What are the disadvantages with DM?
Some people take the metaphor of direct manipulation too literally
Not all tasks can be described by objects and not all actions can be done directly
Some tasks are better achieved through delegating
e.g. spell checking
Can become screen space ‘gobblers’
Moving a mouse around the screen can be slower than pressing function keys to do same actions

43. 4. Exploring and browsing
Similar to how people browse information with existing media (e.g. newspapers, magazines, libraries, pamphlets)
Information is structured to allow flexibility in way user is able to search for information
e.g. multimedia, web

44. Conceptual models based on objects
Usually based on an analogy with something in the physical world
Examples include books, tools, vehicles
Classic: Star Interface based on office objects
Johnson et al (1989)

45. Another classic: the spreadsheet (Bricklin)
Analogous to ledger sheet
Interactive and computational
Easy to understand
Greatly extending what accountants and others could do

46. Which conceptual model is best?
Direct manipulation is good for ‘doing’ types of tasks, e.g. designing, drawing, flying, driving, sizing windows
Issuing instructions is good for repetitive tasks, e.g. spell-checking, file management
Having a conversation is good for children, computer-phobic, disabled users and specialised applications (e.g. phone services)
Hybrid conceptual models are often employed, where different ways of carrying out the same actions is supported at the interface - but can take longer to learn

47. Interface metaphors
Interface designed to be similar to a physical entity but also has own properties
e.g. desktop metaphor, web portals
Can be based on activity, object or a combination of both
Exploit user’s familiar knowledge, helping them to understand ‘the unfamiliar’
Conjures up the essence of the unfamiliar activity, enabling users to leverage of this to understand more aspects of the unfamiliar functionality

48. Benefits of interface metaphors
Makes learning new systems easier
Helps users understand the underlying conceptual model
Can be very innovative and enable the realm of computers and their applications to be made more accessible to a greater diversity of users

49. Problems with interface metaphors
Break conventional and cultural rules
e.g. recycle bin placed on desktop
Can constrain designers in the way they conceptualize a problem space
Conflict with design principles
Forces users to only understand the system in terms of the metaphor
Designers can inadvertently use bad existing designs and transfer the bad parts over
Limits designers’ imagination in coming up with new conceptual models

50. Conceptual models: from interaction mode to style
what the user is doing when interacting with a system, e.g. instructing, talking, browsing or other
Interaction style:
the kind of interface used to support the mode, e.g. speech, menu-based, gesture

51. Many kinds of interaction styles available…
Command
Speech
Data-entry
Form fill-in
Query
Graphical
Web
Pen
Augmented reality
Gesture and even...

52. Interacting via GPS enabled cell phone…
Drawing an elephant by walking round the streets of a city (or other mode of transport) and entering data points along the way via the cell phone
Example: Brighton and Hove(UK) by J. Wood by foot, track length 11.2km (see for more examples)

53. Making art by recording where walking in a city

54. Which interaction style to choose?
Need to determine requirements and user needs
Take the budget and other constraints into account
Also will depend on suitability of technology for activity being supported
This topic will be covered more later when discuss how to actually design conceptual models

55. Interaction paradigms
Another form of inspiration for conceptual models
From the desktop to ubiquitous computing (embedded in the environment)

56. Examples of new paradigms
Ubiquitous computing (mother of them all)
Pervasive computing
Wearable computing
Tangible bits
Augmented reality
and many more….

57. Summary points
Important to have a good understanding of the problem space
Fundamental aspect of interaction design is to develop a conceptual model
Interaction modes and interface metaphors provide a structure for thinking about which kind of conceptual model to develop
Interaction styles are specific kinds of interfaces that are instantiated as part of the conceptual model
Interaction paradigms can also be used to inform the design of the conceptual model