HCI Lecture 1: Principles, Study Guides, Projects, Research of Design

Download HCI Lecture 1: Principles and more Study Guides, Projects, Research Design in PDF only on Docsity! 1 HCI Lecture 1: Principles Hiroshi Shimodaira Key points: –  Definition and related fields –  HCI in the design process –  General framework –  The action cycle and causes of error –  Standards, rules and principles NB: The slides were created by Barbara Webb. 2 Definition and Related fields   "Human-computer interaction is a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them." Association for Computing Machinery –  Equivalent terms are CHI and MMI –  Usability Engineering focuses on design and implementation process   Earlier fields of Human Factors & Ergonomics –  More stress on physical issues; and on optimising (work) processes; concerns interaction with all kinds of human artifacts   User Interface Design –  Focus on interface, i.e. tends to assume deeper function is fixed   User/Human Centred Design –  Approach to software engineering with user focus at all stages –  Participatory Design explicitly includes users in design process   Interaction Design –  Wider scope than computer, and more emphasis on cognitive/ experiential factors than traditional HF. 5 HCI in the design process   Agile development e.g. eXtreme Programming (agilemanifesto.org): emphasises tight iteration in short timescales, close collaboration with customer Sharp, Preece & Rogers, 2007, p.458 6 General Framework   Complex problem: we don’t have a full theory of the parts, or their interactions   Note that a particular desired outcome may be best achieved by changing any one of these factors or interactions. Human Task Computer Environment Interface Input Output Articulation Observation Presentation Performance 7 Why is interaction difficult?   Examples of errors 10 Norman’s Action Cycle   Norman proposed that actions are performed in cycles: 1.  Establish a goal 2.  Execute the action 3.  Evaluate the action 11 Norman’s Action Cycle 2.  Stages of execution A.  Form a plan for the task, a sequence of system operations to be performed on system entities B.  Translate the plan into an action specification consistent with the interface ‘input’ language C.  Output the action specification as a sequence of lexical tokens using the system input devices 12 Norman’s Action Cycle 3.  Stages of evaluation D.  Observe the system response as e.g., visual, auditory tokens generated by output devices E.  Interpret the output in terms of changes in the system state, e.g., entity properties F.  Determine whether the new system state is consistent with what was intended 15 Errors High-level: unable to conceive or recognise goal satisfaction •  Cannot determine correct thing to do, or make wrong choice •  Uncertainty about outcome or mistaken belief that have made progress towards the goal 16 Design Rules for HCI   principles –  abstract design rules –  “an interface should be easy to navigate”   guidelines –  advice on how to achieve principle –  may conflict; understanding theory helps resolve –  “use colour to highlight links”   standards –  specific rules, measurable –  “MondoDesktop links are RGB #1010D0”   Many sets of rules have been proposed to encapsulate understanding and best practice –  Operate at various levels 17 Design Rules for HCI   ISO 9241, Ergonomics of Human System Interaction, adopts traditional usability categories with specific measures, e.g.: 20 Design Rules for HCI Nielsen’s 10 Usability Heuristics (1994): 1.  Visibility of system status 2.  Match between system and the real world 3.  User control and freedom 4.  Consistency and standards 5.  Help users recognize, diagnose and recover from errors 6.  Error prevention 7.  Recognition rather than recall 8.  Flexibility and efficiency of use 9.  Aesthetic and minimalist design 10. Help and documentation 21 Consolidate the three lists here. Mark any you don’t understand with * E.g. Consistency (Nor 7,Shn 1, Nie 4) 22 Usability Principles from Dix Chapter 7 Dix groups these and related principles as follows:   Learnability –  the ease with which new users can begin effective interaction and achieve maximal performance (e.g. familiarity, generalisability, predictability)   Flexibility –  the multiplicity of ways the user and system exchange information (e.g. customisability, substitutability, user control)   Robustness –  the level of support provided to the user in determining successful achievement and assessment of goal-directed behaviour (e.g. observability, recoverability)