Lesson 1 in Human Computer Interaction PDF

HUMAN COMPUTER INTERACTION Get Started PART 1: INTRODUCTION 01. Usability of Interactive Systems 02. Universal Usability 03. Guidelines, Principles, and Theories  Human Computer Interaction HCI is a discipline that deals with the theory, design,...

HUMAN COMPUTER INTERACTION Get Started PART 1: INTRODUCTION 01. Usability of Interactive Systems 02. Universal Usability 03. Guidelines, Principles, and Theories  Human Computer Interaction HCI is a discipline that deals with the theory, design, implementation, and evaluation of the ways that humans use and interact with computing devices. HCI is characterized as a dialogue or interchange between the human and the computer because the output of one serves as the input for the other in an exchange of actions and intentions. It is the study of interaction between people (users) and computers. HCI is an interdisciplinary field in which computer scientists, Computer Speech- Science Ergonomics engineers, psychologists, Language & Human social scientists and design Pathology Factor professional play important Information roles. Security Engineering The knowledge gained from this study is used to create information systems and Psychology HCI Design work environments which help to make people more Cognitive Sociology & Social productive and more Science Psychology satisfied with their work. Ethnography Why is it important? Enable us to design interactive products to support people in their every day and working lives. Develop usable products: easy to learn effective to use provide an enjoyable experience  In general, the focus of HCI is on the design, implementation, and evaluation of interactive computer-based systems for human use. Ensuring the safety, utility, effectiveness, efficiency, accessibility, and usability of systems is the focal concern of HCI. It is also concerned with the multidisciplinary study of various issues affecting this interaction. 01. Usability of Interactive Systems 1.1 Usability Requirements Usability requires project management and careful attention to requirements analysis and testing for clearly defined objectives. Goals for requirements analysis: Ascertain the users’ needs. Ensure proper reliability. Promote appropriate standardization, integration, consistency, and portability. Complete projects on schedule and within budget. 1.2 Goals for Requirements Analysis 1.2.1 Ascertain the user’s needs Determine what tasks and subtasks must be carried out. Include tasks which are only performed occasionally. Common tasks are easy to identify. Functionality must match need or else users will reject or underutilize the product. Providing excessive functionality is also a danger because the complexity make implementation, learning and usage more difficult. 1.2 Goals for Requirements Analysis 1.2.2 Ensure reliability Actions must function as specified. Database data displayed must reflect the actual database The system should be available as often as possible The system must not introduce errors Ensure the user's privacy and data security by protecting against unwarranted access and destruction of data 1.2 Goals for Requirements Analysis 1.2.3 Promote standardization, integration, consistency, and portability Standardization: use pre-existing industry standards where they exist to aid learning and avoid errors. e.g. the W3C, ISO, Apple, and Windows interface standards Integration: the product should work with different software tools and packages Consistency: use common action sequences, terms, units, colors, etc. within the program compatibility across different product versions compatibility with related paper and other non-computer based systems Portability: allow for the user to convert data and to share user interfaces across multiple software and hardware environments 1.2 Goals for Requirements Analysis 1.2.4 Complete projects on time and within budget Late or over budget products can create serious pressure within a company and potentially mean dissatisfied customers and loss of business to competitors 1.3 Usability Measures Determining the target user community and set of tasks is the basis for establishing usability goals and measures. For each user and each task, precise measurable objectives guide the designer, evaluator, or manager. Communities evolve and change 1.3 Usability Measures The ISO 9241 standard "Ergonomics requirements for office work with visual display terminals (VDTs)“ – a set of international standards for using computers, including hardware, visual display, and interaction guidelines. Usability The effectiveness, efficiency, and satisfaction with which specified users achieve specified goals in particular environments. Effectiveness The accuracy and completeness with which specified users can achieve specified goals in particular environments. Efficiency The resources expended in relation to the accuracy and completeness of goals achieved. Satisfaction The comfort and acceptability of the work system to its users and other people affected by its use. 1.3 Usability Measures The following usability measures lead more directly to practical evaluation: Time to learn How long does it take for typical members of the community to learn actions relevant to a set of tasks? Speed of performance How long does it take to carry out the benchmark tasks? Rate of errors by users How many and what kinds of errors are made during benchmark tasks? Retention over time How well do users maintain their knowledge after an hour, a day, or a week? Frequency of use and ease of learning help make for better user retention Subjective satisfaction How much did users like using various aspects of the interface? The answer can be ascertained by interviews, free-form comments and satisfaction scales 1.3 Usability Measures Every designer like to succeed in every category, but trade-offs in design options frequently occur. task-performance vs. time to learn speed of performance vs. error rate Design alternatives can be evaluated by designers and users via mockups or high-fidelity prototypes. 02. Universal Usability 2.0 Universal Usability Usable by all or most users Understanding the physical, intellectual and personality differences between users is vital for getting participation by broadest set of users Sometimes accommodating the needs of one group benefits other groups as well. 2.0 Universal Usability 2.1 Physical abilities and physical workplaces Basic data about human dimensions comes from research in anthropometry There is no average user, either compromises must be made or multiple versions of a system must be created Physical measurement of human dimensions are not enough, take into account dynamic measures such as reach, strength or speed 2.0 Universal Usability 2.1 Physical abilities and physical workplaces (cont.) Differences in perceptual abilities Vision: depth, contrast, color blindness, and motion sensitivity Touch: keyboard and touch-screen sensitivity Hearing: audio clues must be distinct Workplace design can both help and hinder work performance For an individual For multiple workstations 2.0 Universal Usability 2.2 Cultural and international diversity Accommodating cultural and international differences will increases the market share of interactive products. User interface design concerns for internationalization: Characters, numerals, special characters Left-to-right versus right-to-left versus vertical input and reading Date and time formats Numeric and currency formats Weights and measures Telephone numbers and addresses Social-security, national identification, and passport numbers Capitalization and punctuation Sorting sequences Icons, buttons, colors Etiquette, policies, tone, formality 2.0 Universal Usability 2.3 Users with Disabilities Designers must plan early to accommodate users with disabilities Vision-impaired hearing-impaired mobility-impaired 2.4 Elderly Users Including the elderly is fairly easy; designers should allow for variability within their applications via settings for sound, color, brightness, font sizes, etc. If elder people can use the technology easily, we have more opportunities of knowing about their experiences 2.0 Universal Usability 2.5 Children Designers need attention to their limitations. They may not always do mouse-dragging, double-clicking or pointing on small targets. Usual instructions and error messages might not be effective Parental control over dangerous content 2.6 Accommodating hardware/software diversity Internet interaction on high-speed (broadband) and slower (dial-up) connections Access to web services from large displays and small mobile devices Easy or automatic conversion to multiple languages 03. Guidelines, Principles, and Theories 3.0 Guidelines, Principles, and Theories Guidelines: Low-level focused advice about good practices and cautions against dangers Principles: Mid-level strategies or rules to analyze and compare design alternatives Theories: High-level widely applicable frameworks to draw on during design and evaluation, as well as to support communication and teaching –Theories can also be predictive, such as those for pointing times by individuals or posting rates for community discussions 3.1 Guidelines A guideline document helps by developing a shared language & promoting consistency among multiple designers (in terminology usage, UI appearance, and action sequences) Based on best practices Critics: –Guideline documents are too specific, incomplete, hard to apply, and sometimes wrong Proponents: –Encapsulate experience, contribute to improvements 3.1 Guidelines The early Apple and Microsoft guidelines, which were influential for desktop-interface designers, have been followed by dozens of guidelines documents for the Web and mobile devices. Example of Apple guidelines for designing menus for the iWatch: 3.1 Guidelines 3.1.1 Navigating the interface Standardize task sequences Ensure that embedded links are descriptive Use unique and descriptive headings Use check boxes for binary choices Use radio buttons for mutually exclusive choices Develop pages that will print properly Use thumbnail images to preview larger images 3.1 Guidelines 3.1.2 Accessibility guidelines Provide a text equivalent for every non-text element For any time-based multimedia presentation, synchronize equivalent alternatives Information conveyed with color should also be conveyed without it (e.g., with sound) Title each frame to facilitate identification and navigation 3.1 Guidelines 3.1.3 Organizing the display Consistency of data display (terminology, formats, colors, delimiters, capitalization) Efficient information assimilation by the user / minimal input actions by user (justification, spacing, # of decimal points, appropriate units, comprehensible labels, abbreviations, etc.; avoid duplications) Minimal memory load on the user Compatibility of data display with data entry Flexibility for user control of data display 3.1 Guidelines 3.1.4 Mobile HCI Design Constraints/Guidelines Design constraints Smaller screen size Touch data entry can cause errors Battery-power limitations Data download speed or access Design Guidelines Ensure spatial consistency Show high-level information Minimize number of steps (taps) Minimize data entry Focus on goals and optimize tasks Follow emerging standards from manufacturers 3.1 Guidelines 3.1.5 Getting the user’s attention Intensity - use two levels only, with limited use of high intensity Marking – various ways: underline the item, enclose it in a box, point it with an arrow, use an asterisk, bullet, dash, + or X sign Size – use up to 4 sizes Choice of fonts – use up to 3 fonts Blinking– use this method cautiously [2-4 Hz] Color – use up to 4 standard colors Animation – use it only when meaningful Audio – soft tones [regular] vs. harsh tones [emergency] Avoid cluttered screens, don’t overuse the above 3.1 Guidelines 3.1.6 Facilitate data entry Similar sequences of actions speed up learning Fewer input actions mean greater operator productivity, and usually less error; avoid redundant data entry Users should not be required to remember lengthy lists of codes The format of data-entry information should be linked closely to the format of displayed information, such as dashes in telephone numbers Experienced users prefer to enter information in a sequence that they can control, such as selecting the color first or size first, when clothes shopping 3.2 Principles More fundamental, widely applicable, and more enduring than guidelines Need more clarification Fundamental principles Determine user’s skill levels Identify the tasks Choose between five primary interaction styles Apply 8 golden rules of interface design Prevent errors Ensure human control while increasing automation 3.2 Principles 3.2.1 Determine the user’s skill levels “Know thy user” Age, gender, physical and cognitive abilities, education, cultural or ethnic background, training, motivation, goals and personality Design goals based on skill level Novice or first-time users Knowledgeable intermittent users Expert frequent users Multi-layer designs, personalized menus, control of informative feedback 3.2 Principles 3.2.2 Identify the tasks Task analysis usually involve long hours observing and interviewing users Decomposition of high level tasks Relative task frequencies, basis for design decisions 3.2 Principles 3.2.2 Identify the tasks (cont.) 3.2 Principles 3.2.3 Choose an interaction style Direct manipulation Menu selection Form fill-in Command language Natural language 3.2 Principles 3.2.3 Choose an interaction style (cont) 3.2 Principles 3.2.3 Choose an interaction style (cont) Spectrum of directness 3.2 Principles 3.2.4 The 8 golden rules of interface design Strive for consistency Cater to universal usability Offer informative feedback Design dialogs to yield closure Prevent errors Permit easy reversal of actions Keep users in control Reduce short term memory load 3.2 Principles 3.2.5 Prevent errors Make error messages specific, positive in tone, and constructive Mistakes and slips (Norman, 1983) Correct actions Gray out inappropriate actions Selection rather than freestyle typing Automatic completion Complete sequences Single abstract commands Macros and subroutines 3.2 Principles 3.2.5 Ensuring human control while increasing automation Successful integration: Users can avoid: Routine, tedious, and error prone tasks Users can concentrate on: Making critical decisions, coping with unexpected situations, and planning future actions Supervisory control needs to deal with real world open systems E.g., air-traffic controllers with low frequency, but high consequences of failure FAA: design should place the user in control and automate only to improve system performance, without reducing human involvement 3.2 Principles 3.2.5 Ensuring human control while increasing automation (cont.) Goals for autonomous agents Know user's likes and dislikes Make proper inferences Respond to novel situations Perform competently with little guidance Tool-like interfaces vs. autonomous agents Avatars representing human users, not computers, more successful 3.2 Principles 3.2.5 Ensuring human control while increasing automation (cont.) User modeling for adaptive interfaces Keeps track of user performance Adapts behavior to suit user's needs Allows for automatically adapting system Response time, length of messages, density of feedback, content of menus, order of menu items, type of feedback, content of help screens Can be problematic System may make surprising changes User must pause to see what has happened User may not be able to predict next change interpret what has happened restore system to previous state 3.2 Principles 3.2.5 Ensuring human control while increasing automation (cont.) Alternative to agents, systems that enable: user control, responsibility, accomplishment extended use of control panels (settings, options, preferences) Game levels Style sheets for word processors Information-visualization tools Scheduling software 3.2 Principles 3.2.5 Ensuring human control while increasing automation (cont.) Users employ control panels to set physical parameters, such as the cursor blinking speed or speaker volume, and to establish personal preferences such as time/date formats, color schemes, or the content of start menus. 3.2 Principles 3.2.6 Ensuring human control while increasing automation (cont.) 3.3 Theories Beyond the specifics of guidelines, Principles are used to develop theories Some theories are descriptive (describe user interfaces & their uses) Explanatory - describe sequences of actions Prescriptive – offer guidelines to make decisions Predictive – offer predictions, e.g. on speed or errors Some theories are based on human capacity Motor – pointing, clicking, dragging, other movements Perceptual – visual, auditory, tactile, other Cognitive – problem solving with short and long-term memory 3.3 Theories 3.3.1 Explanatory and predictive theories Explanatory theories: Observing behavior Describing activities Conceiving designs Comparing high-level designs Training Predictive theories: Enable designers to compare proposed designs for execution time or error rates 3.3 Theories 3.3.2 Perceptual, Cognitive & Motor tasks Perceptual or cognitive subtasks theories Predicting reading times for free text, lists, or formatted displays Motor-task performance times theories: Predicting keystroking or pointing times 3.3 Theories 3.3.3 Taxonomies (part of descriptive theories) Order on a complex set of phenomena Facilitate useful comparisons Organize a topic for newcomers Guide designers Indicate opportunities for novel products 3.3 Theories *Taxonomy example (not of theories, but of VR systems) 3.3 Theories 3.3.4 Conceptual, semantic, syntactic, and lexical model [design-by-levels theories] (Foley and van Dam, 1995) four-level approach – model for interfaces: Conceptual level: User's mental model of the interactive system Semantic level: Describes the meanings conveyed by the user's command input and by the computer's output display Syntactic level: Defines how the units (words) that convey semantics are assembled into a complete sentence that instructs the computer to perform a certain task Lexical level: Deals with device dependencies and with the precise mechanisms by which a user specifies the syntax This approach is convenient for designers Top-down nature is easy to explain Matches the software architecture Allows for useful modularity during design 3.3 Theories 3.3.5 Stages of action theory Norman's seven stages of action model Forming the goal Forming the intention Specifying the action Executing the action Perceiving the system state Interpreting the system state Evaluating the outcome Norman's contributions Context of cycles of action and evaluation. Gulf of execution: Mismatch between the user's intentions and the allowable actions Gulf of evaluation: Mismatch between the system's representation and the users' expectations 3.3 Theories 3.3.6 Stages of action models Four principles of good design State and the action alternatives should be visible Have a good conceptual model with a consistent system image Interface should include good mappings that reveal the relationships between stages User should receive continuous feedback Four critical points where user failures can occur Users can form an inadequate goal Might not find the correct interface object because of an incomprehensible label or icon May not know how to specify or execute a desired action May receive inappropriate or misleading feedback 3.3 Theories 3.3.7 Consistency theories Consistent user interface through grammar Definition is elusive – multiple forms sometimes in conflict Sometimes advantageous to be inconsistent Inconsistent action verbs Take longer to learn, cause more errors, slow down users, and are harder for users to remember 3.3 Theories 3.3.8 Contextual Theories Micro-HCI Theories Focus on measurable performance (such as speed and errors) on multiple standard tasks taking seconds or minutes in laboratory environments Design-by-levels Stages of action Consistency Macro-HCI Theories Focus on case studies of user experience over weeks and months, in realistic usage contexts with rich social engagement Contextual Dynamic 3.3 Theories 3.3.8 Contextual Theories (cont.) User actions are situated by time and place You may not have time to deal with shortcuts or device dependent syntax (such as on mobile devices) when hurried Physical space is important in ubiquitous, pervasive and embedded devices, e.g. a museum guide stating information about a nearby painting A taxonomy for mobile device application development could include: Monitor and provide alerts, e.g. patient monitoring systems Gather information Participate in group collaboration Locate and identify nearby objects or sites Capture information about the object and share that information 3.3 Theories 3.3.9 Dynamic Theories Dynamic theories owe much to theories of adoption or innovation diffusion. Attributes: Relative advantage: faster, safer, more error free, cheaper Compatibility: fitting users’ needs Trial-ability: availability to experiment with innovation Observability: visibility of innovation to others Less complexity: ease of learning and use Used by designers of online communities and user-generated content sites Example, Reader-to-Leader model THANK YOU End Of Slides