Improve Productivity less error faster task completion

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Wilfred McGee
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Goals review 1 Improve Productivity less error faster task completion Class Goals Understand user parameters for future software development and evaluation Review software interaction styles and

1 Goals review 1 Improve Productivity less error faster task completion Class Goals Understand user parameters for future software development and evaluation Review software interaction styles and their applicability Survey Interaction devices and their use. Speculate on future HCI environments Understand HCI methodology for the evaluation of HCI research. Understand guidelines for user interfaces, graphical user interfaces, and graphical user interface implementation.

2 HCI review 2 Users Cognitive models of people as information processing systems Exploit the common, acknowledge, accommodate, individual differences Knowledge about how people perform at different tasks human factors Tasks Categories, transfer of learning / skills Frequency, definition Modifiability, existence of multiple operations & strategies Systems Output graphics, sound speech, tactile Input keyboard, mouse, controller gesture, speech Ubiquitousin-situ, mobile / wearable (AR)

3 HIP review 3 "Systems" metaphor of multiple processors and memories to explain human cognitive behavior Assumes rational, goal directed actions. (but. see next slide) perceptual cognitive Form intention: acquire task, make mental representation of goal Select action: review possible actions, select appropriate action motor Execute action Evaluate system response

4 Decision Making Model review 4 Two cognitive human decision making systems: System 1: automatic, unconscious, approximate, easy, visual, emotional / sensational, fast System 2: conscious, deliberate, rational, precise, difficult, verbal, slow Most decisions are made with system 1 (default system) Losses > Gains risk averse but like to gamble and take risks Sensational, Memorial > Statistics, Factual fears flying, prefers to drive good story, familiar source rather that facts Important decisions should be made with system 2, but its harder, requires concentration. Application to HCI: provide inferences (minimize system 2, do some thinking for user) Explain assumptions and results with examples, memorial stories (1).

5 Models Working Sensory Input Perceptions Semantic Procedural knowledge memory Processing bottleneck Limited awareness User knowledge Syntactic / Semantic procedural Human Performance speed, correctness review 5 Error: intention, mistake, lapse, slip capture, mode, description Individual Differences closure, control, personality, disabilities

6 Tools Compliment Humans review 6 Users Strengths Computer Applications World Knowledge Learner Pattern Matching Analogical Productive Thinking Vision & Sound Limited Awareness Accurate Reproductive Thinking Forgets Individual Differences Weaknesses Fast Accurate Reproductive "Thinking" Never Forgets Non Ambiguous Knowledge Limited World Knowledge Not Analogical Poor Learning Limited Input Senses

7 Interaction Styles are not mutually exclusive review 7 Menu (M) + choices & mode displayed, slips / syntactic errors + structure conveys structure/meaning, mistakes / semantic errors + selection w/ few keystrokes, slips, learning, error recovery Command Line (CL) + variable length cmds and args, slips && mistakes + large command set, productivity && learning Direct Manipulation (DM) + objects visible on screen selections, resources, programs, errors + user manipulated objects to perform tasks, errors + actions visible, incremental, reversible, errors recovery, learning Task's syntactic command requirements, source of slip errors specific / arbitrary to task, must be taught, not representative of task Task's semantic command requirements, source of mistakes analogous to task, skill transferrable across tasks, less training

8 Negative affordance indicating no capability; an inactive button or a link is greyed out. Has potential to positive.. Affordances The perceived and actual properties of a thing or image. review 8 Perceptual object s characteristics imply appropriate action. Pattern set by conventions, Windows system min, max, close box in upper right window corner. Hidden affordance must be shown, mouse hover, right click False affords something else that is unexpected or not working. Web page broken link, or URL to unexpected site. Metaphorical capabilities know by association to real objects: e- commerce site using a shopping cart icon for purchases

9 Direct Vs. Indirect Pointers review 9 Direct Pointers: stylus / pen (lightpen, touchscreen), touch / gesture + User selects and manipulates objects on display directly with pointer device. More natural (touchscreen). + Fast positioning - Pointing on vertical display causes fatigue. - Less accurate, pointing can block view of display. In-Out touchscreen positioning can help accuracy Indirect Pointers (mice, joystick) - User positions a "pointer" icon on screen with a pointer device. The pointer device does not contact the display. - Positioning less "natural", a learned skill + View not blocked, less fatigue

10 Response Time Models review 10 <think time> <make response time> <system response time> GOMS model, "scripting model" for HCI tasks {Goals} ( goal ( subgoal ( sg (... )))) {Operators} cmds, behaviors, available {Methods} plans for using operators to achieve goals {Selectors} evaluate among possible methods Keystroke model T unit task = T acquire + T execute T execute = T k + T p + T h + T m + T r Menu items, linear choice, visual scan t = c + scan item * nitems/2 grouped items (branch is a equally likely group) t = c + k response slope log branching_factor Fitts' law time to move pointer device to target t = c + k log (distancetotarget/targetwidth)

11 Sources of information review Real World" observations: naturalistic, unobtrusive observations, observations of experts, case studies. strong mundane realism, strong generalization to "real environments" 2. Experimental observations: strong experimental realism precise data collection in controlled artificial environment Mundane Evidence + Initial source of beliefs + Generalizability - Spurious - Slow Experimental Evidence + Convergent validations + Quantitative + Discovery - Hawthorne effect - Generalizability Knowledge

12 UI Guidelines review 12 Know the user Know the task! Describe Before you Leap Present what is needed, not all there is Eliminate Mode Errors Prove that Help Helps Integrate help w/ error processing Handle Errors to Teach & be Productive

13 review 13 Designers make myths. Users make conceptual models.

14 performance Learning and Limited Working Memory C learning and use Minimize Conceptual Load. A no rules many independent terms B few rules review 14 humans change they: learn recognize patterns many rules c o n c l e o p a t d u a l

15 GUI Design review 15 Objects in task domain are visible: often icons + planning is a recognition (not recall) task + low syntactic & semantics memory icons semantics by analogy + spatial / visual tasks learned faster + visual memory retained longer User directly manipulates task object. Actions and results are visible, incremental, reversible {embedded icon = menu, pull down, pop up}. + no complex syntax for commands. + modeless or visible mode (greyed, disabled menu items) + minimizes slips GUI weaknesses - Repetitive tasks maybe hard to combine or parameterize, as in command line. - Iconic interfaces may suffer description errors, visual interferences.

16 Grids: modularity in visual structure GUI Windows are rectangular grids are the first display layout considered. Regular visual structures are predictable, flexible, and efficient. review 16 Grids benefit design and provide "scalability" to a GUI application. As screens and dialogs increase in numbers a grid layout simplifies design and increases use. Canonical grid layout enables 6, 4, 3, and 2 division of elements on a display. Bootstrap web UI framework Any remaining visible grid lines should be half intensity in final display

17 Interface Builders and Interface Description Languages Interface Builders (IB) and Interface Description Languages (IDL) enable Drag and Drop construction of GUI's (in many APIs) IB, IDL 17 example: Visual Studio(2013) WPF / C# Designer interface

18 Visual Displays review 18 No more than 6 colors (including black) should be used on one screen. Backgrounds should not be brighter than foregrounds. Grid lines should be half intensity Do not have extreme color contrasts between foreground and background colors -- causes afterimages due to rod fatigue. Use white for critical / important dynamic information (color gun fails) A monochrome flash of twice intensity is as effective as color use. Separate significant information on display by size, distance, intensity or highlighting. Use screen position consistently. Time / Date info or page number in same place. Groups screen elements. Provide title for elements. Hard to title than grouping is poor.

19 Semiotics -- GUIs as signs Iconic sign Representation review 19 representation resembles object Symbolic sign viewer associates representation and object Object Representation Interpreter class Object Interpreter Generality instance??? Abstractness helps iconic generality Realistic icons represent instances Minimal Abstractness Stylized (minimalistic) icons

= 1D variable don't present 1 D data in a 3D chart Chart Junk recall of information detection of information lie = 2.

20 Information Visualization review 20 Beware visual lie factor = size of effect in graphic / size of effect in data use size of effects as percentages Respect the dimensionality of the data area (2D)!= 1D variable don't present 1 D data in a 3D chart Chart Junk recall of information detection of information lie = 2.8 Poor visual literacy of Information Visualization techniques. non-linear projections: distort straight lines magnify "focus" regions heat map color coding?

21 Text in Interfaces review 21 Conversation (spoken) is natural, humans have innate language ability, learning almost effortless Writing (reading) is not an innate ability, learning requires effort Reading feature-driven > context driven graphic design (gestalt) Minimize text Use common, frequent, simple language Avoid busy, complex, "difficult" fonts and spacing foreground > background, good contrast, mute simple background appropriate justification for culture (usually not centered) information > grammar, bullet lists, minimize repetition

22 Human processing guidelines review 22 Time (second) Perpectual cognitive UI deadline (min or max) detect audio gap smallest audio gap 0.01 pre-conscious perception visual detection 0.1 saccadic eye movment perceive cause-effect viusal fushion (flicker) object identification perceptual flicker 1 max conversation gap visual-motor recaction attentional blink 10 unborken task concentration unit task unconscious familiarity generate tone / pitch pen / e-ink lag time feedback mouse click display busy indicators 10 fps (24+ fps better) display progress long task max response rate delay serial information display (RSVP) system step completion 100 critical decision, emergency present all critical information

23 HCI Future review 23 "It's the business of the future to be dangerous" -- M. McLuhan Hardware is not THE limitation. Software and "mindware" is. HCI will continue to increase in importance, privacy may decrease... User Interfaces multi-dimensional (here and there now), augmented / immersive environments. The pace / change in user system interaction is increasing. Software architecture a multi-disciplinary, multi-media, multi-knowledge base (semantic web), activity. HCI HSI (Human System Interfaces). Ubiquitous We will be symbiotes in a "thing intelligent" world (agents). We will be augmented: carry-able wearable implantable Become more artistic: artistic is technological (artists are 1 st adopters). Practice safe / ergonomic computing organic repair/upgrade is rare.

Adapted from: The Human Factor: Designing Computer Systems for People, Rubinstein & Hersh (1984) Designers make myths. Users make conceptual models.

User Interface Guidelines UI Guidelines 1 Adapted from: The Human Factor: Designing Computer Systems for People, Rubinstein & Hersh (1984) Know your users - they are not you Designers make myths. Users