Designing Interfaces for Human Activities

1. AVI/Psych 358/IE 340: Human Factors Interfaces and Interaction September 22, 2008

2. Designing Interfaces • Human-Computer Interaction (HCI) has moved beyond designing interfaces for desktop machines • Concerned with extending and supporting all aspects of human activities through design and evaluation (social, emotional, physical etc.)

3. Understanding the problem space • What do you want to create? • What are your assumptions? • What are your claims? • Will it achieve what you hope it will? If so, how?

4. An example • What do you think were the main assumptions made by developers of online photo sharing and management applications, like Flickr?

5. Assumptions • Able to capitalize on the hugely successful phenomenon of blogging • Just as people like to blog so will they want to share with the rest of the world their photo collections and get comments back • People like to share their photos with the rest of the world

6. From problem space to design space • Having a good understanding of the problem space can help inform the design space • But before deciding upon these it is important to develop a conceptual model

7. What is a conceptual model? • “a high-level description of how a system is organized and operates.” • What functionality to provide • What would the website do (overall) • Who would use it? • E.g.: a university website, or Orbitz, youtube etc.

8. Why do we need it? • NOT a description of the user interface • But a structure outlining the concepts and the relationships between them • Helps the design team

9. Ponzo’s illusion • Ambiguity • Human mind perceives object’s size based on the background • Interpret based on a linear perspective • Moon illusion (bigger at the horizon than at the top)

10. A classic conceptual model: the spreadsheet

11. Why was it so good? (1/2) • It was simple, clear, and obvious to the users how to use the application and what it could do • “It is just a tool to allow others to work out their ideas and reduce the tedium of repeating the same calculations.”

12. Why was it so good? (2/2) • Capitalized on user’s familiarity with ledger sheets • Got the computer to perform a range of different calculations and recalculations in response to user input

13. Interface metaphors • Designed to be similar to a physical entity but also has own properties • e.g. desktop metaphor, search engine, trash • Exploit user’s familiar knowledge, helping them to understand ‘the unfamiliar’ • People find it easier to learn and talk about what they are doing at the computer interface in terms familiar to them

15. Problems with interface metaphors (Nelson, 1990) • Breaks the rules • Too constraining • Limits understanding around metaphor • Conflicts with design principles • Limits designers’ imagination

16. Interaction types • Instructing • Conversing • Manipulating • Exploring

17. Instructing • Where users instruct a system by telling it what to do • A main benefit of instructing is to support quick and efficient interaction

18. Conversing • Like having a conversation with another human • Ranges from simple voice recognition menu-driven systems to more complex ‘natural language’ dialogues • Examples include search engines, advice-giving systems, and help systems

19. Ask Jeeves for Kids!

20. Manipulating • Exploit’s users’ knowledge of how they move and manipulate in the physical world • Virtual objects can be manipulated by moving, selecting, opening, and closing them

21. Direct manipulation • Shneiderman (1983) coined the term Direct Manipulation • Proposes that digital objects be designed so they can be interacted with analogous to how physical objects are manipulated • Assumes that direct manipulation interfaces enable users to feel that they are directly controlling the digital objects

22. Core principles of DM • Physical actions and button pressing instead of issuing commands with complex syntax • Rapid reversible actions with immediate feedback on object of interest

23. Discussion • Give some examples of DM for Windows (e.g., desktop, Microsoft Word)

24. Why are DM interfaces so enjoyable? (1/2) • 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

25. Why are DM interfaces so enjoyable? (2/2) • 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

26. What are the disadvantages of DM? • Some people take the metaphor of direct manipulation too literally • Some tasks are better achieved through delegating rather than manipulation, e.g., spell checking • Moving a mouse around the screen can be slower than pressing function keys to do same actions (e.g., shortcuts)

27. Video game controllers • Compare the direct manipulation between the Wii remote and other traditional video game controllers (e.g., Xbox, PlayStation)

28. Exploring • Involves users moving through virtual or physical environments

29. A virtual world

30. A CAVE

31. Summary points • Need to have a good understanding of the problem space • specifying what it is you are doing, why, and how it will support users in the way intended • A conceptual model is a high-level description of a product (not the interface) • what users can do with it and the concepts they need to understand how to interact with it

32. Summary points • Decisions about conceptual design should be made before commencing any physical design • Interface metaphors are commonly used as part of a conceptual model • Interaction types (e.g., conversing, instructing) provide a way of thinking about how best to support the activities users will be doing when using a product or service

33. Summary points • Different types of interactions • Instructing • Conversing • Manipulating • Exploring