# Presentation: 095285

## 
Key Dismukes, PhD
	Chief Scientist for Aerospace Human Factors 

NASA Ames Research Center

12 January 2002

- Key Dismukes, PhD
- 	Chief Scientist for Aerospace Human Factors
- NASA Ames Research Center
- 12 January 2002

**Lessons from Aviation:  ****Memory, Skilled Human Performance,  and All-too-human Error**

## 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

## 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?

## 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

## 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.

## 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

## 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

##     Attributes of the Model

**    ****Attributes of the Model**

**Memory**

**More accessible**

- Activated
- representations

**Activation**

**  ****Very limited capacity**
**  ****Currently attended representations**
**  ****Dynamic flow of contents**
**  ****Representations compete to enter **
**   ****attention based on level of activation**

**External Stimuli**

**Less accessible**

- Long-term memory
-   very large capacity

**Focal Attention**

## Attributes: Activation and Retrieval of Memory Representations

**Attributes: Activation and Retrieval of Memory Representations**

**Memory**

**More accessible**

**Activation**

**“****horse”**

**External Stimuli**

**Less accessible**

- Long-term memory

**Focal Attention**

**horse**

-  **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**

**More accessible**

## Attributes: Goals are Memory Representations

**Attributes: Goals are Memory Representations**

**Memory**

**More accessible**

**Activation**

**prepare **
**vuegraph**

**External Stimuli**

**Less accessible**

- Long-term memory

**Focal Attention**

**prepare**
**talk**

**schedule**
**conference **
**room**

**floss**
**daily**

**win **
**Nobel prize**

- 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

**More accessible**

## 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

## Prospective Memory as Competing Concurrent Task

**Prospective Memory as Competing Concurrent Task**

**Memory**

**More accessible**

**Activation**

**lion**

**External Stimuli**

**Less accessible**

- Long-term memory

**Focal Attention**

**lion**

- rate
- pleasantness

- Participate
- in experiment

**animal**

**press**
**key**

**Prospective task competes with pleasantness rating  for retrieval**
**On-going task has inherent advantage **
**Outcome is probabilistic **
**Depends on multiple factors**

**More accessible**

## 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

## 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

## Slide 15

## 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

**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**

**Flight Crews Manage Multiple ****Tasks Concurrently**

## Examples of Neglected Tasks

** ****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**

**Examples of Neglected Tasks**

- 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)

- Aviation Incident Study

## Examples of Neglected Tasks

** ****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**

**Examples of Neglected Tasks**

- Aviation Incident Study

## 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**

## 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**

- Omitting a Procedural Step

## 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

- 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

**Training Implications**

## Error Management Training

**Change in historic attitude**
**Errors are inevitable**
**Training should address:**
- Recognizing potential threats
- Detecting errors
- Managing error outcome

**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**

**Training Implications**