1. Lessons from Aviation: Memory, Skilled Human Performance, and All-too-human Error
Key Dismukes, PhD
Chief Scientist for Aerospace Human Factors
NASA Ames Research Center
12 January 2002

2. Examples from one domain of error: prospective memory
Road Map of Talk
A cognitive perspective on error   vulnerability of skilled professionals
Examples from one domain of error:   prospective memory
Lapses in everyday life
Lapses in flight operations
Implications for professional training

3. Most Airline Accidents Attributed to Crew Error
Society: error = blame
Misrepresents nature of cognitive skill
Undercuts safety
Research on human factors in aviation safety
Extrapolate to other professional domains?

4. Aircrew Performance
Trained to high level of performance; daily practice; annual recurrent training
Monitored periodically by check pilots
Highly motivated
NTSB accident reports reveal few examples of incompetence or malfeasance

5. Two Fallacies about Error
Fallacy: Error can be eliminated if pilots are sufficiently  vigilant, conscientious, and proficient.
Truth: Vigilant, conscientious experts routinely make errors.
Fallacy: If an accident crew made errors in tasks that pilots routinely handle without difficulty, that accident crew must have been in some way deficient — either they lacked skill, or had a bad attitude, or just did not try hard enough.
Truth: The fallacy ignores sampling bias. No matter how many times an expert performs a procedure perfectly, the probability of error is greater than zero.

6. A Cognitive Perspective
Simply trying hard will not prevent errors
Unique human capabilities enabled by biological information-processing mechanisms
Vulnerable to error
Error is probabilistic, not deterministic
Illustrate with research on memory errors

7. Prospective Memory (PM)
Remembering to perform an action that  must be delayed
Relatively new field of human memory  research
Defining characteristics:
Delay between forming intention and opportunity to   execute (seconds to years)
Delay filled with other tasks that occupy attention
No explicit prompt telling us it is time to execute intention
So how do we ever remember to perform   intentions?
A theoretical perspective

8. Attributes of the Model
Focal Attention
Very limited capacity
Currently attended representations
Dynamic flow of contents
Representations compete to enter
attention based on level of activation
External Stimuli
More accessible
Activated
representations
Activation
Memory
Long-term memory
very large capacity
Less accessible

9. Attributes: Activation and Retrieval of Memory Representations
Focal Attention
External Stimuli
horse
“horse”
animal
More accessible
Currently attended representation
provides activation to associated item
in memory
Activation increases as function of
time in attention
Activation decays as function of time
since last attended
Activation is finite and divided among
associates
Activation is divided according to
strength of links to associate
cowboy
“horse”
More accessible
saddle
racing
Activation
Memory
Indian
Less accessible
Long-term memory

10. Attributes: Goals are Memory Representations
Focal Attention
External Stimuli
prepare
vuegraph
More accessible
More accessible
prepare
talk
Deferred intentions are a form of goal
Goals are represented as condition/action associates (If…then)
Goals are associated in hierarchies of sub-goals
Sub-goal in focal attention helps maintain activation of higher goal
Activation
schedule
conference
room
Memory
Less accessible
win
Nobel prize
floss
daily
Long-term memory

11. Einstein-McDaniel PM Paradigm
Instruct subjects to perform cover task   (e.g., reading a paragraph or rating pleasantness of   series of words)
  Give additional (PM) task   (e.g., “Press slash key when see a name of an animal”)
  Subjects begin performing cover task
  Delay between starting cover task and trial with   animal name
  Must remember to perform PM task without   prompting

12. Prospective Memory as Competing Concurrent Task
Focal Attention
External Stimuli
lion
lion
rate
pleasantness
animal
More accessible
lion
More accessible
press
key
Prospective task competes with pleasantness rating for retrieval
On-going task has inherent advantage
Outcome is probabilistic
Depends on multiple factors
cat
Activation
cub
Memory
Participate
in experiment
Africa
Less accessible
Long-term memory

13. Implications for Real-World Performance
Cannot maintain delayed intentions in   focal attention
Must retrieve from memory when opportunity for   execution arises
Retrieval requires noticing some cue associated   with intention
Availability of cues and noticing cues is haphazard
Thus, memory lapses are commonplace

14. Strategies
Importance of delayed intention does not   prevent memory lapses
Simply trying harder is ineffective
Strategies may help to some degree:
Habitual review: what do I need to do now?
Encode environmental cues likely to be present in window of opportunity for execution
Create salient cues that must be processed during ongoing task

16. Flight Crews Manage Multiple Tasks Concurrently
Cockpit operations are highly proceduralized
Taxi, climb out, descent, and arrival are sometimes quite busy
Each pilot is responsible for multiple concurrent tasks (e.g., searching for traffic and flying the airplane)
Interruptions, distractions, or preoccupation with one task to the detriment of another found in nearly half of NTSB accident reports
Issue may be management of attention rather than overload

17. Examples of Neglected Tasks
Aviation Incident Study
Examples of Neglected Tasks
Lapses in monitoring (2/3 of reports)
Aircraft position: taxi, altitude capture, navigation
Aircraft status: systems, automation
Actions of other crew member
Lapses in prospective memory (1/4 of reports)
Complete interrupted procedure on checklist
Retract speed brakes when leveling-off descent
Reset flaps and bleed air after de-icing
Stop fuel transfer
Set take-off flaps when deferred
Defer lowering landing gear in minimum fuel situations

18. Competing Tasks that Distracted or Preoccupied Pilots
Aviation Incident Study
Competing Tasks that Distracted or Preoccupied Pilots
50% involved communication (e.g., conversation with other crewmembers/flight attendants, radio communication, ATIS, PAX announcements).
16% involved “head-down” tasks (e.g., paperwork, FMS entry, reviewing charts)
14% involved abnormals
8% involved searching for/responding to traffic
12% miscellaneous (e.g., decision-making, unstabilized approach)

19. Examples of Neglected Tasks
Aviation Incident Study
Examples of Neglected Tasks
Lapses in monitoring (2/3 of reports)
Aircraft position: taxi, altitude capture, navigation
Aircraft status: systems, automation
Actions of other crew member
Lapses in prospective memory (1/4 of reports)
Complete interrupted procedure on checklist
Retract speed brakes when leveling-off descent
Reset flaps and bleed air after de-icing
Stop fuel transfer
Set take-off flaps when deferred
Defer lowering landing gear in minimum fuel situations

20. Omitting a Procedural Step
Highly practiced procedures vulnerable to omission when:
Interrupted
Performed outside normal sequence or context
Highly practiced procedures become largely automatic
Allows fast, smooth execution
Requires minimal conscious supervision
Execution largely under control of environmental cues
Most common error in maintenance: omitting a step in re-assembly
Example: finish tightening spark plugs

21. Why So Easy to Forget a Procedural Step?
Omitting a Procedural Step
Why So Easy to Forget a Procedural Step?
With highly practiced procedures, retrieval of each step triggered by:
Current state of environment
Execution of immediately preceding step
Interruption breaks chain of preceding steps -- no trigger
Environment may seem to indicate uncompleted step has been performed
No episodic memory trace for habitual actions

22. Prospective Memory Countermeasures
Training Implications
Prospective Memory Countermeasures
Recognize the threat
Vulnerable even when tasks are important and delays are short
Especially vulnerable: Interruptions and performing habitual procedures out of normal sequence
Explicitly note interruption and identify when/where intention will be executed
In team situation, say aloud
Create salient reminder cues*
Avoid rushing procedures
Periodically review status and ask if anything is missing
Use checklists*
* Not always practical

23. Line Oriented Flight Training (LOFT)
Training Implications
Line Oriented Flight Training (LOFT)
Full-mission simulation
Normal operations and challenging situations (e.g., weather diversions, equipment failures)
Should include realistic:
Concurrent task demands
Interruptions
Distractions
Delays

24. Error Management Training
Training Implications
Error Management Training
Change in historic attitude
Errors are inevitable
Training should address:
Recognizing potential threats
Detecting errors
Managing error outcome

25. Error Data from Routine Operations
Training Implications
Error Data from Routine Operations
What errors occur, circumstances, and how professionals respond
Accident/incident reports useful but are a limited and biased sample
LOSA: Line Operational Safety Audits
Large sample of daily operations
Data on threats, errors, and how crews manage
Comprehensive and realistic picture of challenges
LOSA + laboratory research   powerful new approaches to training