1. Distributed Cognition
How a Cockpit Remembers Its Speeds
Edwin Hutchins

2. Classical Cognitive Science
Thinking about thinking
Mental processes
Individual human agent
How information is represented
Transformed
Combined
Propagated
Nature of knowledge

3. Distributed Cognition
Unit of analysis
Processes within system
Representations
External
Internal

4. Cognitive Systems Organizations Role of material media
Physical processes
Human actors
Material media
Interactions
Explicit nature of environment

5. Context: MD-80 Cockpit Representations inside cockpit system
External to pilots
Procedure = behavioral properties
Constraint-based
Workers-finish-design

6. Task: Memory Task Remembrance of speeds For subsequent use
For proper & safe
Initial descent
Approach to land
Instrument landing

7. Artifacts: Wing Shape

8. Artifacts: Speed Card & Fuel

9. Artifacts: ASI & Speed Bugs

10. Actors: Pilot Roles Two pilots/stations
Complete dual-flight instrumentations
Pilot Flying (PF)
Pilot Not Flying (PNF)

11. [Cross-checks & verbal communication]
Process Description
Prepare landing data ( min. out)
Determine gross weight (Fuel Qty)
Find correct speed card (2000 lb. incr)
Post speed card
Set speed bugs on both ASIs
Descent - slow plane & configure wings
Final approach to land - Vref
[Cross-checks & verbal communication]
At about 1,000 feet AFL, the crew will select the final flap setting of 28° or 40°, and maintain the approach speed. At 500 feet AFL, the PNF calls out the altitude, the airspeed relative to the approach airspeed, and the descent rate. For example, "Five hundred feet, plus four, seven down," meaning, 500 feet above the field elevation, 4 knots faster than desired approach speed, descending at 700 feet per minute. The pilot not-flying may also specify relation to the glide slope, indicating whether the airplane is below, on, or above the glide slope. Once final flaps are set on the final approach segment, the PNF calls out airspeed whenever it varies more than plus or minus 5 knots from approach speed.

12. Cognitive Description-External
How are speeds represented?
How are representations
Transformed,
Processed,
Coordinated?
How does the system’s memory work?

13. Observable Representations
Gross-weight display (Fuel Qty)
Speed card booklet
ASIs & speed bugs
Speed-select of Flight Director
Verbal exchanges between pilots
Setting bugs
Cross-checks
Call-outs /progress reports

14. Additional Representations
Memory of each pilot
Individual considered as part of system
Media in the cockpit
Task environment forms memory
Internal representations

15. Speed Card & Gross Weight
Long-term memory
Gross weight
Appropriate speeds
Functionally durable
Filtered information
Correct weight = correct speeds
Distributed access
Social space
Knowledge

16. Distribution & Transformation
Transformations of representations
Verbal (as relayed between PNF & PF)
Via speed bug settings
Cross-checking & redundancy
Time-critical procedure indications

17. Configuration Changes
Speed determined
ATC instruction
Position in approach
ASI needle nears appropriate bug
PF calls for flap/slat configuration
PNF configures flaps/slats
Verification & cross-checks
(with speed card)

18. Salmon Speed Bug Final approach speed reference (Vref)
Spatial relation with ASI needle
PF to track speed
PNF to determine deviations
Verbal representation of call-outs
Lightens demand on visual load of PF

19. External Representations Summary
Speed bugs
Resource for later processes
Durable working memory
Coordinated representations
Verbal
Speed card/fuel qty
Configurations
“System memory”

20. Cognitive Description-Internal
Cognitive tasks of pilots
Task specification
Not procedural recount
Provide constraints on useable
Representations
Processes
Interpretation not recall
Function in system memory

21. Speed Card & Gross Weight
Pattern matching
Implicit learning
Internal structure for prediction
Interpret values
Card design
Working memory
Setting bugs - varied sequences

22. Configuration Change Bugs
Numerical relations
Spatial position
Space of speeds
“Configuration zones”
Superimposing representations
Functional systems

23. Configuration Zones

24. Salmon Speed Bug Numerical relation Scale of ASI and need positioning
Spatial proximity
Scale-reading task
Base of salmon bug
Verbal call-out - aural cue

25. Notion of Memory Traditionally a psychological function
A series of tasks in a functional system
Recognition & recall
Pattern matching
Cross-modal transformations
Distributed
Among human agents
Between human agents
Transformed external representations

26. Workers Finish the Design
Provides constraints and artifacts
Salmon bug
Engineer’s design
Ease of location
Ease of interpolation
Pilot’s use
Determine 5-kt. deviations
Not anticipated by designer (engineer)

27. Cockpit as Cognitive System
Unit of analysis
Transforms & propagates information
Use of representations
Notion of memory task
Redundant & robust