Morten Fjeld HCI Course, Spring term 2006

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Bryce Dickerson
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1 Practical information 1/2 Previous course: Go to Spring 2005 Chapter 3: Interaction by Morten Fjeld Partly based on Dix et al. Exercise report: Do not copy your pal! Hand in of exercises: Tuesdays 16:00! Hand in of assignment: Important dates & times Assignment draft: Is compulsory/necessary Wish for for a Forum: Who wants it? who would use? Exercise 2: Questionary from Dix, Interviews from Preece 1/59 2/59 Practical information 2/2 Assigment tutoring in Restaurant Linsen -- Wednesday 1st February, 09:00-11:00 -- Wednesday 8th February 14:00-16:00 3/59 Lecture overview interaction models translations between user and system ergonomics physical characteristics of interaction interaction styles the nature of user/system dialog button layout in touch screen design a case study, NOT in text book, but compulsory elements of the WIMP interface windows, icons, menus, pointers 4/59 What is interaction? communication user system models of interaction but is that all? terms of interaction Norman model interaction framework 5/59 6/59 1

2 Some terms of interaction What about untraditional interaction? domain the area of work under study e.g. graphic design goal what you want to achieve e.g. create a solid red triangle task how you go about doing it ultimately in terms of operations or actions e.g. select fill tool, click over triangle Note traditional interaction use of terms differs a lot especially task/goal!!! 7/59 Photo: Andreas Kunz, ETH Zurich 8/59 Donald Norman s model Seven stages user establishes the goal formulates intention (after goal!) specifies actions at interface executes action perceives system state interprets system state evaluates system state with respect to goal Norman s model concentrates on user s view of the interface 9/59 execution/evaluation loop execution goal system 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 10/59 evaluation execution/evaluation loop execution goal system evaluation 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 execution/evaluation loop execution goal system evaluation 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 11/59 12/59 2

with respect to goal http://aviationweather.gov/static/images/fa/fa-gulf.png 13/59 National Centers for Environmental Prediction, Kansas City, MO, USA http://aviationweather.

3 execution/evaluation loop What is a gulf? Something you want to overcome, cross. goal execution evaluation system 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 13/59 National Centers for Environmental Prediction, Kansas City, MO, USA 14/59 Using Norman s model Human error - slips and mistakes Some systems are harder to use than others Gulf of Execution user s formulation of actions actions allowed by the system Gulf of Evaluation user s expectation of changed system state actual presentation of this state 15/59 slip understand system and goal correct formulation of action incorrect action (human error) mistake may not even have right goal! (human error) Fixing things? slip better interface design mistake better understanding of system 16/59 Ergonomics ergonomics physical aspects of interfaces industrial interfaces Study of the physical characteristics of interaction Also known as human factors but this can also be used to mean much of HCI! Ergonomics good at defining standards and guidelines for constraining the way we design certain aspects of systems 17/59 18/59 3

Ergonomics - examples Surrounding environment, table heights arrangement of controls and displays e.g. controls grouped according to function or frequency of use, or sequentially surrounding environment e.

g. use of red for warning, green for okay, awareness of colour-blindness etc.

Light conditions: ERGO LIGHT Industrial interfaces Office interface vs. industrial interface?

office industrial type of data textual numeric rate of change slow fast environment clean dirty http://www.

4 Ergonomics - examples Surrounding environment, table heights arrangement of controls and displays e.g. controls grouped according to function or frequency of use, or sequentially surrounding environment e.g. seating arrangements adaptable to cope with all sizes of user health issues e.g. physical position, environmental conditions (temperature, humidity), lighting, noise, use of colour e.g. use of red for warning, green for okay, awareness of colour-blindness etc. 19/59 20/59 Surrounding environment, table heights Surrounding environment, examples / /59 Light conditions: ERGO LIGHT Industrial interfaces Office interface vs. industrial interface? Context matters! office industrial type of data textual numeric rate of change slow fast environment clean dirty 23/59 24/59 4

5 Glass interfaces? Indirect manipulation industrial interface: traditional dials and knobs now screens and keypads glass interface + cheaper, more flexible, multiple representations, precise values not physically located, loss of context, complex interfaces may need both Vessel B Temp multiple representations of same information office direct manipulation user interacts with artificial world industrial indirect manipulation user interacts with real world interface through interface immediate issues.. feedback feedback instruments delays system plant 25/59 26/59 Common interaction styles interaction styles command line interface menus natural language question/answer and query dialogue form-fills and spreadsheets WIMP point and click three dimensional interfaces 27/59 28/59 Command line interface Menus Way of expressing instructions to the computer directly function keys, single characters, short abbreviations, whole words, or a combination suitable for repetitive tasks better for expert users than novices offers direct access to system functionality command names/abbreviations should be meaningful! Typical example: the Unix system 29/59 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 30/59 5

6 Natural language Query interfaces 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 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 31/59 32/59 Form-fills Spreadsheets Primarily for data entry or data retrieval Screen like paper form. Data put in relevant place Requires good design obvious correction facilities first spreadsheet VISICALC, followed by Lotus MS 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 33/59 34/59 WIMP Interface (more later) Three dimensional interfaces 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 35/59 virtual reality ordinary window systems highlighting visual affordance click me! 3D workspaces use for extra virtual space light and occlusion give depth distance effects 36/59 flat buttons or sculptured 6

7 A propos Click Me! Case Study: Towards Guidelines for Touch Screen Design: Perception of Button Size and Height Fjeld, Zuberbühler, Guttormsen, Voorhorst, Krueger ETH Zurich, Switzerland Published paper: Case study Overview Motivations and previous reseach Experimental set-up Observations Results Design insights Future research issues Case Study: Touchability of Touch Screens 37/59 Case Study: Touchability of Touch Screens 38/59 Motivation Touch screen designers generally have few or no guidelines to choose standard solutions. Hence, there is a need for guidelines to support designers of touch screen buttons; that is, button form, size, and positioning. Related issues are texture and colours used for the background and for buttons. Previous research by Fred A. Voorhorst Exp. 1: Classifying surfaces Exp. 2: Textured buttons Exp. 3: Contrasting textures Case Study: Touchability of Touch Screens 39/59 Case Study: Touchability of Touch Screens 40/59 Main conclusion of previous research When it comes to perceiving difference between touch screen buttons perceived BUTTON SIZE and perceived BUTTON HEIGHT are of greatest importance. We decided to explore perceptual thresholds for these two factors. Experimental set-up 1/2 Evaluation of design-relevant visual perceptual cues for the design of touch screens Button form (round and rectangular) and button extensions (size and height) were examined For each of the two forms; with size and height as visual perceptual cues, we estimated perceptual threshold in terms of pixels. Case Study: Touchability of Touch Screens 41/59 Case Study: Touchability of Touch Screens 42/59 7

Experimental set-up 2/2 Within-group design with four conditions 12 subjects were presented with 16 varieties of a find-and-select task; 8 tasks with lower time limit (2 seconds) and 8 tasks with

8 Experimental set-up 2/2 Within-group design with four conditions 12 subjects were presented with 16 varieties of a find-and-select task; 8 tasks with lower time limit (2 seconds) and 8 tasks with higher time (8 seconds) limit Task at typical start-up Condition (rectangular, height) +10 Estimation of the perceptual threshold by dynamic adaptation using best-pest method; 50% level Test environment was coded in Director/Lingo Case Study: Touchability of Touch Screens 43/59 Case Study: Touchability of Touch Screens 44/59 Condition (row) and stimulus (column): unmodified; #pixels threshold; task start-up.??? Observations 1/3 Perceptual thresholds, box plots? +10 Case Study: Touchability of Touch Screens 45/59 Case Study: Touchability of Touch Screens 46/59 Observations 2/3 Observations 3/3 RectH RectS RoundH RoundS Perceptual threshholds in # pixels Pixel, mean Pixel, SD Pixel, integer Ranking button form and cue by # pixels (lo to hi): Case Study: Touchability of Touch Screens 47/59 Case Study: Touchability of Touch Screens 48/59 8

9 Results Main conclusion Button height should be preferred over button size as perceptual cue, which is equally valid for round and rectangular buttons Secondary conclusions If height is chosen as cue, round buttons should be preferred If size is chosen as cue, rectangular buttons should be preferred elements of the wimp interface windows, icons, menus, pointers +++ buttons, toolbars, palettes, dialog boxes Case Study: Touchability of Touch Screens 49/59 50/59 Windows Icons 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 51/59 small picture or image represents some object in the interface often a window or action windows can be closed down (iconised) small representation fi many accessible windows icons can be many and various highly stylized realistic representations. 52/59 Pointers Menus 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 Choice of operations or services offered on the screen Required option selected with pointer File Edit Options Font Typewriter Screen Times problem take a lot of screen space solution pop-up: menu appears when needed 53/59 54/59 9

10 Kinds of Menus Menus design issues 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 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! 55/59 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 56/59 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 57/59 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 58/59 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. 59/59 10

chapter 3 the interaction

chapter 3 the interaction ergonomics physical aspects of interfaces industrial interfaces Ergonomics Study of the physical characteristics of interaction Also known as human factors but this can also be