1 Chapter 8: Displays System Display (the represented system) Mental model Senses Attention Perception

2 Display design principles n Perceptual principles 1) Absolute judgement (maximum of 5-7 levels) 2) Top-down processing (Highlight the unexpected) 3) Redundancy gain (Multiple cues or modes) 4) Discriminability (ratio of similar to dissimilar features) n Attention principles 5) Minimizing information access cost (minimize “distance” between variables) 6) Proximity compatibility principle (link variables through common location, color, or other code) 7) Principle of multiple resources (distribute information between mental resources) n Mental model principles 8) Principle of pictorial realism (configure to match system/mental model, thermometer) 9) Principle of the moving part (match movement to system/mental model, aircraft and altimeter) 10) Ecological interface design (display provides an externalized and normative mental model) n Memory principles 11) Predictive aiding (show future states rather than force people to estimate) 12) Knowledge in the world (displayed information rather than rely on memory) 13) Consistency (same cues should have same meaning, red is for danger)

3 Attention principles n Minimizing information access cost (minimize “distance” between variables, same page for related information) n Proximity compatibility principle (link variables through common location, color, or other code) n Principle of multiple resources (distribute information between mental resources, such as auditory and visual modes)

4 Mental model principles n Principle of pictorial realism (configure to match system/mental model, thermometer) n Principle of the moving part (match movement to system/mental model, aircraft and altimeter) n Ecological interface design (display provides an externalized and normative mental model)

5 VCR metaphor for printer?

6 Dimmer Switch

7 Memory principles n Predictive aiding (show future states rather than force people to estimate) n Knowledge in the world (displayed information rather than rely on memory, position estimates on chart) n Consistency (same cues should have same meaning, red is for danger)

8 From Barrows and Powell (2000)

9 Display design principles n Perceptual principles 1) Absolute judgement (maximum of 5-7 levels) 2) Top-down processing (Highlight the unexpected) 3) Redundancy gain (Multiple cues or modes) 4) Discriminability (ratio of similar to dissimilar features) n Attention principles 5) Minimizing information access cost (minimize “distance” between variables) 6) Proximity compatibility principle (link variables through common location, color, or other code) 7) Principle of multiple resources (distribute information between mental resources) n Mental model principles 8) Principle of pictorial realism (configure to match system/mental model, thermometer) 9) Principle of the moving part (match movement to system/mental model, aircraft and altimeter) 10) Ecological interface design (display provides an externalized and normative mental model) n Memory principles 11) Predictive aiding (show future states rather than force people to estimate) 12) Knowledge in the world (displayed information rather than rely on memory) 13) Consistency (same cues should have same meaning, red is for danger)

10 Types of displays n Alerting n Labels n Monitoring n Multiple displays n Navigation displays and maps n Tables and graphs

11 Alerting n Perceptual: Redundancy gain (use auditory because it is omnidirectional) n Perceptual: Absolute judgement (limit number of warning tones to 5-7) n Memory: Consistency (uniform meaning for color codes)

12 Labels n Perceptual: Discriminability n Attention: Proximity compatibility principle n Asymmetry in interpretation of negative Right turn only vs. No left turn

13 Monitoring n Perceptual: Absolute judgement and display markings n Mental model: Ecological interface design n Mental model: Principle of pictorial realism and analog and digital displays. DEPENDS ON TASK

14 Traditional Interface

15 Rankine Cycle Interface

16 Specific benefits of the Rankine cycle display n Distinctive shape makes changes easy to identify (highlights the unexpected) n Changes in shape are linked to a model of the underlying physics and so support problem solving (externalized mental model) n Temperature and pressure data are placed in a meaningful context (Knowledge in the world rather than steam tables in the head)

17 Multiple displays n Attention: Minimizing information access cost using the primary visual area, phase-related tailoring n Memory: Consistency of display layout n Attention/Mental model: Information grouping

18 Multiple displays n Attention: Costs and benefits of head-up displays n Perceptual: Discriminability and emergent features of configural displays

19 Navigation displays and maps n Perceptual: map clutter (color, intensification, and declutter/filtering functions) n Map orientation: Head up vs North up n 3-D vs 2-D: Role of topography, experience of users ;

20 Tables and graphs n Perceptual: Discriminabilty, differentiating lines in a line graph n Perceptual: Discriminabilty, minimizing clutter n Attention: Proximity compatibility and linking lines to legend

21 Objectives n Power of representation n Display variables and the match to the task n Display design principles Perceptual Mental model Attention Memory n Types of displays and how to apply the principles