User Interfaces 4 BTECH: IT WIKI PAGE: https://userinterfaces4.wikispace.com
User modelling • Types of user model • User models and evaluation • Interface evaluation methods
Types of user model • Psychological theories as user models • Task analysis for user models • Cut-down psychological theories as user models • Simplistic psychological theories as user models • More: Search for Norman’s (1988) model Norman’s model (2004) for emotional design
1. Psychological theories as user models • Complex • Requires expert knowledge • Simplified for HCI use
2. Task analysis for user models • Analysis of core tasks lead to how users undertake these tasks • Reinventing the wheel • Good theories already exist • Behaviouristic approach
3. Cut-down psychological theories as user models • Model Human Processor Perception Short Term Memory Long-Term Memory Cognitive Processing Response
4. Simplistic psychological theories as user models • Combine Task analysis and Model Human Processor • Provide powerful conceptual framework to accommodate complex theories and research • Ability to be repackage to be used as a guide
Initial version of Simplex One Adams, R and Landon, P. 2003. Principles and Concepts for Information and Communication Technologies Design. Journal of Visual Impairment and Blindness, October. 5 Zones to consider
Input Output Zone • Input/ Output zone: • Easy to perceive and understand? • Should input be changed to improve perceptual resource use of the individual? • Picture -> Text? • Systems allows most suitable ways to generate output? • When are traditional devices, keyboard and mouse, not best option?
Memory Zones • Long term data warehouse (long term memory) • Do users have to have learned large amounts of tacit knowledge to navigate through the system? • Abstract working memory (short term memory) • Is amount of information an individual is required to hold to navigate the system too much? • Does design increase memory problems for visually impaired?
Central Processor/Executive functions • Learning the overall task, organization and implementation • Transfer information between zones • Manageable tasks, or steep learning curve required • Does design provide support? • Balance between what to remember and what to do?
Advances Simplex Theory Adams, R and Landon, P. 2003. Principles and Concepts for Information and Communication Technologies Design. Journal of Visual Impairment and Blindness, October
4 Extra zones • Feedback to the user: good quality understandable feedback • Emotional response to the system: is it fun to use? • Cognitive models: Mental models to aid understanding • Complex and skilled response sequences: dos the sign support the development of such sequences?
Principles for evaluation • Guidelines, Rules and standards • Guidelines (principles): more general • Rules: specific are based on studies • Standards: International Standards Organisation, standards for industrial software
ISO 9241-11 • Defines usability as “the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a special context of use”.
Well Known Design Principles • Learnability • Predictability • Consistency • Flexibility • Recoverability • Responsiveness
User models assist design • Use model to determine user requirements • Use models to determine profiles of target users • Use models to evaluated proposed designs • Use to generate questions to either of the above
Questions for perception • What are the perceptual skills of the target users? • Do the symbols/icons make sense to the target users? • Do the symbols/icons/colours convey the same nuances/meanings to all the target users? • Examples: • Perception relies on past experiences, motivation and development
Questions for Responses • What are user responses likely to be? • How will the environment influence user responses? • Should a variety of responses be accepted?
What is abstract working memory Short-term memory (or "primary" or "active memory") is the capacity for holding a small amount of information in mind in an active, readily available state for a short period of time. The duration of short-term memory (when rehearsal or active maintenance is prevented) is believed to be in the order of seconds. A commonly cited capacity is 7 ± 2 elements. Short-term memory should be distinguished from working memory, which refers to structures and processes used for temporarily storing and manipulating information. Working memory refers to structuresand processes used for temporarily storing and manipulating information
Questions for abstract working memory • What kind of memory capabilities do the targets users have? • What other factors will impact on the capacity of the working memory? • Examples: selection of pass words, user names
Questions for Long-term memory • Are the metaphors used intuitive? • Does the interface offer support to remember things? • Does the interface offer different levels of support for remembering? • Does the interface offer different ways of retrieving knowledge? • Examples: Database construct search without fields being visible, technical terms SSL, ports, etc
Questions for Executive Functions • What steps are required to convert input into the intended output? • Are the steps interchangeable? • How much user interaction is required for data to be moved from one area to another? • Examples: • Formula construction in spreadsheets • Database reports
Evaluation Methods • Usability testing involves • a method to test the system, • a product or system to be tested and • somebody to test the system. • 3 main groups of evaluating: inspection, testing and inquiry • Inspection: experts evaluate interfaces, example heuristic walkthroughs, … • Testing: keystrokes, eye tracking, calculations • Inquiry: contextual inquiry, ethnographic study/field observation, interviews and focus groups, surveys and questionnaires, users evaluate the interface
Exercise • Construct 2 questions for each zone of your cell phone to determine usability