Human Factors in Information Displays

Robert Mauro

Human Factors in Aviation

University of Oregon

Spring 2004

Display Design Process

• The display design process should begin with:

– Cognitive Task Analysis: Systematic analysis of the psychological factors that affect an operator’s performance in a situation.

– Information Needs Analysis: Analysis of what information the operator needs to accomplish the task.

Fundamental Principles of Information Displays

• Principle of Need

• Principle of Legibility

• Principle of Display Integration/Proximity

• Principle of Pictorial Realism

• Principle of the Moving Part

• Principle of Predictive Aiding

• Principle of Discriminability

Principle of Need

• Give operators what they need to know, when they need it.

• Corollary: If the information isn’t needed, don’t provide it.

– Example: Map of the London Underground

Actual Geography

Schematic Representation

Principle of Legibility

• Visual Displays

– Display size

• large enough for details to be easily resolved

– Contrast & Brightness

• adequate for all levels of illumination and glare

– Color

• distinct differences for different information

• Auditory Displays

– Loudness

• loud enough to be easily heard over ambient noise

– Clarity

• static low enough to make sounds/speech distinct

– Frequency

• distinct differences for different information

• Example: NWS Map Clutter

Attempt to display too much information on a single display

Map clarified by elimination of information and addition of color

Dimensions of information ~ Dimensions of representation

Principle of Display Integration/Proximity

• When mental integration or comparison is required, displays should be proximally located.

– Examples

• Primary Flight Instruments

• Standard Navigation Instruments

• Horizontal Situation Indicator

Principle of Pictorial Realism

• Representation should resemble information it depicts.

– Examples

• Physical resemblance

• Metaphorical resemblance

• Old style attitude indicator

– completely symbolic display

• New style attitude indicator

– enhanced pictorial realism

• Depth display

– Left

• garish, unnatural

• difficult to interpret

– Right

• subtle, natural

• easy to interpret

Tufte (1993)

Principle of the Moving Part

• If it moves in the real world (or the operator’s mental model of the world) it should move in the display.

– Roscoe AI (1968)

Principle of Predictive Aiding

• When the operator must anticipate future states, the display should indicate those states whenever the prediction is reasonably accurate.

– Example: Flight Director

– Place wedge in chevrons

Principle of Discriminability

• Different types of information should be easily discriminable.

– Example

• Weather depictions

Summary Examples

• TCAS

– Integrated information

– Altitude relative to aircraft

– Trend information for predictive aiding

– Auditory warnings

– Auditory resolutions

• ATC Display

– Integrated display

– Trend information

– 2 dimensional representation

– 3^rd dimension digital

• Airbus PFD

– Speed tape on right

– Altitude tape on left

• Pitch up (towards higher numbers) for speed to go down.

– Ground moves, aircraft is stable

• Regional Jet Panel

• Cirrus General Aviation Instrument Panel

– Legible

– Pictorial

– Discriminable

– Integrated

– Moving map

– No predictive aiding

– Standard inverse moving AI