ID Conceptual Models (Mental Models) Summary

1. IDConceptual Models(Mental Models)Summary CSSE 477 October, 2011 From Ch 2 and Ch 8 of the ID book See examples of user models at end!

2. Where you’re using these • In term project, next assignment – • Get user feedback to your prototype • Build / revise a mental model of users • From which you should develop a conceptual model of your system • Then go for system implementation User feedback Mental model of them Conceptual model Of the system Build actual system From big picture

3. User model

4. The user’s mental model of what’s happening 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 Ch 2 Slide 7

5. The user’s mental model of what’s happening 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” Ch 2 Slide 8

6. The user’s mental model of what’s happening 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 Ch 2 Slide 9

7. The user’s mental model of what’s happening 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 Ch 2 Slide 10

8. The user’s mental model of what’s happening 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 Ch 2 Slide 11

9. The user’s mental model of what’s happening Conceptual models based on objects • Usually based on an analogy with something in the physical world • Examples include books, tools, vehicles • Classic: Star Interfacebased on officeobjects Johnson et al (1989) Ch 2 Slide 21

10. The user’s mental model of what’s happening 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 Ch 2 Slide 23

11. The user’s mental model of what’s happening 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 Ch 2 Slide 24

12. The user’s mental model of what’s happening 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 Ch 2 Slide 25

13. The user’s mental model of what’s happening 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 Ch 2 Slide 26

14. The user’s mental model of what’s happening Conceptual models: from interaction mode to style • Interaction mode: • 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 Ch 2 Slide 27

15. The user’s mental model of what’s happening Many kinds of interaction styles available… • Command • Speech • Data-entry • Form fill-in • Query • Graphical • Web • Pen • Augmented reality • Gesture and even... Ch 2 Slide 28

16. System model

17. The resulting conceptual model of your system Conceptual design: from requirements to design • Transform user requirements/needs into a conceptual model • “a 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” • Don’t move to a solution too quickly. Iterate, iterate, iterate • Consider alternatives: prototyping helps Ch 8 Slide 16

18. The resulting conceptual model of your system Three perspectives for a conceptual model • Which interaction mode? • How the user invokes actions • Activity-based: instructing, conversing, manipulating and navigating, exploring and browsing. • Object-based: structured around real-world objects Ch 8 Slide 17

19. The resulting conceptual model of your system Three perspectives for a conceptual model • Which interaction paradigm? • desktop paradigm, with WIMP interface (windows, icons, menus and pointers), • ubiquitous computing • pervasive computing • wearable computing • mobile devices and so on. • Is there a suitable metaphor? • (contd)…. Ch 8 Slide 18

20. The resulting conceptual model of your system Is there a suitable metaphor? • Interface metaphors combine familiar knowledge with new knowledge in a way that will help the user understand the product. • Three steps: understand functionality, identify potential problem areas, generate metaphors • Evaluate metaphors: • How much structure does it provide? • How much is relevant to the problem? • Is it easy to represent? • Will the audience understand it? • How extensible is it? Ch 8 Slide 19

21. The resulting conceptual model of your system Expanding the conceptual model • What functions will the product perform? • What will the product do and what will the human do (task allocation)? • How are the functions related to each other? • sequential or parallel? • categorisations, e.g. all actions related to telephone memory storage • What information needs to be available? • What data is required to perform the task? • How is this data to be transformed by the system? Ch 8 Slide 20

22. The resulting conceptual model of your system Using scenarios in conceptual design • Express proposed or imagined situations • Used throughout design in various ways • scripts for user evaluation of prototypes • concrete examples of tasks • as a means of co-operation across professional boundaries • Plus and minus scenarios to explore extreme cases Ch 8 Slide 21

23. The resulting conceptual model of your system Using prototypes in conceptual design • Allow evaluation of emerging ideas • Low-fidelity prototypes used early on, high-fidelity prototypes used later Ch 8 Slide 22

24. Examples of User Models These are all taken from prior classes. • For a drink recipe system • For a Music Library System • For a shared text editing system • For a customized spreadsheet system • For a Log File Parser System The last one is the most complete, and follows the current assignment!

25. Examples of User Models, cntd 1. For a drink recipe system: • Because the testers are mostly college students, they will immediately understand the problem space. • I believe users of the system will easily figure out how to register, but may be confused by the password rules. I also think they might try and search for a recipe by ingredient instead of by name. I think that they will easily figure out how to add a recipe to their favorites list, as long as they have either a) A list of recipes displayed or b) a recipe selected. If they were to, say, try to start from the main screen and add a recipe to favorites they may be confused. I think users may ask what exactly a recipe is. I also think that adding a recipe will be easily accomplished, and that editing a recipe will be slightly more challenging, as they will have to re-find the recipe they created. After this task has been performed once, replication will be trivial. Users will find the clean interface refreshing. • The interface is a bit like a search engine and a liquor cabinet.

26. Examples of User Models, cntd 2. For a Music Library System (Start of description) • Users of the system will have three basic types, each with different usability concerns: • Requestors: These users will only have access to the song library and be able to submit requests of the songs they are browsing. • Understanding of problem space: Requestors will know what songs they want and what the meaning of song terminology is. There is no assumption that they have any specific familiarity with WMHD or this type of user interface. • Usability Goals: Learnability and Effectiveness. • Interface Metaphor: It’s kind of like the Rose class registration page. You can browse listings and search based on criteria and select. • Design Principles: Visibility and Feedback. The users can use feedback to use the site without the need of instructions. They should be able to do things without a lot of navigation to simply request a song. • Interaction type: Exploring. Users browse the library. • More of this one – see notes, below!

27. Examples of User Models, cntd 3. For a shared text editing system (start of description) • There is currently no system that allows multiple people to edit a document in real-time on multiple computers. This makes peer-programming with someone who is not in the same room very difficult. Current systems either do not allow multiple users to edit the same document at the same time or do not update all the documents in real time. And so it is important that our project meets several usability goals. The system must be easy to learn so that new users will not be hampered by using this system. The system also must allow users to effectively perform text edits without a lot of extra administrative work. It’s also important for the system to be efficient so that edits to a document on one computer show up in real-time on other computers in the session. The target users for our system are developers who are coordinating work from potentially remote locations. Therefore, the interface metaphor is a combination of an online instant messaging program (like AOL Instant Messenger) and a text editor from an Integrated Development Environment (like Visual Studio). More of this one – see notes, below!

28. Examples of User Models, cntd 4. For a customized spreadsheet system • We expect that people will be lost due to the overwhelming amount of data which presented to them within the program. Though we feel the data is very cleanly organized and in good relationship to one another, most typical users will not want to have to take the time to look in depth into all the information. We instead believe that users will want a way to view the information in such a way that they can grep the data “at a glance”. In order to do this, we have built in a graphing feature which displays the data in a clean and very easy to read chart (which is also highly customizable).

29. Examples of User Models, cntd 5. For a Log File Parser System (start of description) • Problem Space Understanding • The usability testers of the system should have a good idea of the problem space. Although the specifics of the log files they will be testing the system with are unknown, they have had experience with going through log files and understand the importance of being able to flag entries or write comments on certain entries. If it were possible to get Northrop Grumman’s engineers to be a part of our usability study, it would likely be more fruitful than using people unfamiliar with the log files, but that isn’t feasible for our usability study on such short notice. • More of this one – see notes, below!