CPIS 354 - Principle of Human Computer Interaction

1. CPIS 354 - Principle of Human Computer Interaction Department of Information Systems Faculty of Computing and Information Technology King Abdul Aziz University Khalid Al-Omar 1

2. Understanding Interaction Lecture 6 2

3. The Interaction • interaction models • translations between user and system • ergonomics • physical characteristics of interaction • interaction styles • the nature of user/system dialog • context • social, organizational, motivational

4. What is interaction? • communication • user  system • but is that all … ? • see “language and action” in chapter 4 …

5. models of interaction Purpose of interaction Norman model interaction framework

6. Purpose of interaction Purpose of interactive system is to aid a user in accomplishing goals/tasks from some application domain. domain – the area of work under study e.g. graphic design, shopping online goal – what you want to achieve e.g. create a solid red triangle, purchase books task – how you go about doing it – ultimately in terms of operations or actions e.g. … select fill tool, click over triangle, Select the products, Fill in the order form, pay

7. Models of Interaction • Interaction involve two complex participants: Systems and users. • In order to allow successful interaction, Interfaces must translate the communication between systems and users. • Why using Model? • Can help to understand complex systems and complex behavior • Can help to understand what is going on in the interaction • Identify the likely root of difficulties

8. Donald Norman’s model • Norman uses this model to demonstrate why some interfaces causes problem to their users. • Seven stages (each stage is an activity of the user) • user establishes the goal e.g. purchase books • formulates intention e.g. connect to the Internet/or ask someone • specifies actions at interface e.g. search • executes action e.g. search for product, fill in form, … • perceives system state e.g. perceives the result (found/not found) • interprets system state e.g. understand the result • evaluates system state with e.g. evaluate the result respect to goal • Norman’s model concentrates on user’s view of the interface

9. goal execution evaluation system execution/evaluation loop • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect to goal

10. goal execution evaluation system execution/evaluation loop • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect to goal

11. goal execution evaluation system execution/evaluation loop • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect to goal

12. goal execution evaluation system execution/evaluation loop • user establishes the goal • formulates intention • specifies actions at interface • executes action • perceives system state • interprets system state • evaluates system state with respect to goal

13. Human error - slips and mistakes slip • understand system and goal • correct formulation of action • incorrect action mistake • may not even have right goal! Fixing things? slip – better interface design mistake – better understanding of system

14. ergonomics physical aspects of interfaces

15. Ergonomics • Ergonomics, also known as human factors, is the scientific discipline that seeks to understand and improve human interactions with products, equipment, environments and systems. • Ergonomics good at defining standards and guidelines for constraining the way we design certain aspects of systems • Some of the Ergonomics example: • Arrangement of controls and displays • surrounding environment • health issues • The use of colour

16. Ergonomics - examples Arrangement …displays surrounding environment health issues - use of colour

17. Arrangement of controls and displays • Controls and displays should be grouped logically to allow rapid access by the user. • Controls grouped and organized according to: • Function: according to their functionality • Frequency of use: how frequently they used • Sequentially: to reflect the order of their use • Arrangement of controls and displays is more important in critical system were users work under pressure. E.g. air traffic control

18. Arrangement ..(cont.) • Arrangement in relation to users positions: • Users should be able to reach all controls necessary and view all displays without excessive body movement. • Critical displays should be at eye level. • Lighting should be arranged to avoid reflection distorting displays. • Controls should be spaced to provide adequate room for the user to manoeuvre

19. surrounding environment • Where the system will be used? By whom the it will be used? Will users sitting, standing, or moving about? • All users should be comfortable by using the system: • For long period of use, users should be seated for comfort, and seats should provide back support. • Seating arrangements adaptable to cope with all sizes of user • If user required to stand, the user should have room to move around to reach all control. • Physical environment will be more critical in specific control.

20. health issues • Poor designs in critical system can results to death. E.g. aircraft crashing • health issues e.g. physical position, environmental conditions (temperature, humidity), lighting, noise, and usage time

21. The use of colour • Colour should correspond to users expectation e.g. Red frequently associated with stop, therefore it can be use for warning e.g. Green frequently associated with go, therefore it can be use for okay. e.g. Yellow frequently associated with standby, therefore it can be use for standby and secondary function. • Colours and culture • Red • China: Good luck, celebration, • Western: Warning, danger, stop

22. interaction styles dialogue … computer and user distinct styles of interaction

23. Common interaction styles • command line interface • menus • natural language • question/answer and query dialogue • form-fills and spreadsheets • WIMP • point and click • three–dimensional interfaces

24. Command line interface • It provide instructions to the computer directly • function keys, single characters, short abbreviations, whole words, or a combination • better for expert users than novices • Powerful: offers direct access to system functionality • Flexible: command has a number of options and parameters • suitable for repetitive tasks • Difficult to use and learn therefore, command names/abbreviations should be meaningful! Typical example: the Unix system

25. Menus • Set of options displayed on the screen • Options visible • less recall - easier to use • rely on recognition so names should be meaningful • Selection by: • numbers, letters, arrow keys, mouse • combination (e.g. mouse plus accelerators) • Often options hierarchically grouped • sensible grouping is needed • Restricted form of full WIMP system

26. Natural language • Familiar to user • speech recognition or typed natural language • Problems • vague • ambiguous • hard to do well! • Solutions • try to understand a subset • pick on key words

27. Query interfaces • Question/answer interfaces • user led through interaction via series of questions • suitable for novice users but restricted functionality • often used in information systems • Query languages (e.g. SQL) • used to retrieve information from database • requires understanding of database structure and language syntax, hence requires some expertise

28. Form-fills • Primarily for data entry or data retrieval • Screen like paper form. • Data put in relevant place • Requires • good design • obvious correctionfacilities

29. Spreadsheets • first spreadsheet VISICALC, followed by Lotus 1-2-3MS Excel most common today • sophisticated variation of form-filling. • grid of cells contain a value or a formula • formula can involve values of other cells e.g. sum of all cells in this column • user can enter and alter data spreadsheet maintains consistency

30. WIMP Interface • Windows • Icons • Menus • Pointers • … or windows, icons, mice, and pull-down menus! • default style for majority of interactive computer systems, especially PCs and desktop machines

31. Point and click interfaces • used in .. • multimedia • web browsers • hypertext • just click something! • icons, text links or location on map • minimal typing

32. Three dimensional interfaces • virtual reality • ‘ordinary’ window systems • highlighting • visual affordance • indiscriminate usejust confusing! • 3D workspaces • use for extra virtual space • light and shadow give depth • distance effects flat buttons … click me! … or sculptured

33. elements of the wimp interface windows, icons, menus, pointers +++ buttons, toolbars, palettes, dialog boxes also see supplementary materialon choosing wimp elements

34. Windows • Areas of the screen that behave as if they were independent • can contain text or graphics • can be moved or resized • can overlap and obscure each other, or can be laid out next to one another (tiled) • scrollbars • allow the user to move the contents of the window up and down or from side to side • title bars • describe the name of the window

35. Icons • small picture or image • represents some object in the interface • often a window or action • windows can be closed down (iconised) • small representation of many accessible windows • icons can be many and various • highly stylized • realistic representations.

36. Pointers • important component • WIMP style relies on pointing and selecting things • uses mouse, trackpad, joystick, trackball, cursor keys or keyboard shortcuts • wide variety of graphical images

37. Menus • Choice of operations or services offered on the screen • Required option selected with pointer problem – take a lot of screen space solution – pop-up: menu appears when needed

38. Kinds of Menus • Menu Bar at top of screen (normally), menu drags down • pull-down menu - mouse hold and drag down menu • drop-down menu - mouse click reveals menu • fall-down menus - mouse just moves over bar! • Contextual menu is a drop-down menus that display a small set of commands and options related to the current context. • Contextual menu appears where you are • pop-up menus - actions for selected object • pie menus - arranged in a circle • easier to select item (larger target area) • quicker (same distance to any option)… but not widely used!

39. Menus extras • Cascading menus (submenu) is secondary menu displayed on demand from within a menu.  • Hierarchy menu structure • menu selection opens new menu • and so in ad infinitum • Keyboard accelerators • key combinations - same effect as menu item • two kinds • active when menu open – usually first letter • active when menu closed – usually Ctrl + letter • usually different !!!

40. Menu techniques Leah Findlater and Krzysztof Z. Gajos, “Design Space and Evaluation Challenges of Adaptive Graphical User Interface”

41. Menus design issues • which kind to use • what to include in menus at all • words to use (action or description) • how to group items • choice of keyboard accelerators

42. Menus design issues Why Microsoft have changed the menu from dropdown menu to tabbed menu? Think about it! Tabbed menu Dropdown • Smart menu • Split menu

43. Buttons • individual and isolated regions within a display that can be selected to invoke an action • Special kinds • radio buttons – set of mutually exclusive choices • check boxes – set of non-exclusive choices

44. Toolbars • long lines of icons … … but what do they do? • fast access to common actions • often customizable: • choose which toolbars to see • choose what options are on it

45. Dialogue boxes • information windows that pop up to inform of an important event or request information. e.g: when saving a file, a dialogue box is displayed to allow the user to specify the filename and location. Once the file is saved, the box disappears.

46. References • HCIBook. “Human Computer Interaction”. ALAN DIX - JANET FINLAY - GREGORY ABOWD - RUSSELL BEALE (http://www.comp.lancs.ac.uk/~dixa/) • Leah Findlater and Krzysztof Z. Gajos, “Design Space and Evaluation Challenges of Adaptive Graphical User Interface”. • http://www.tandf.co.uk/journals/titles/00140139.asp