PSY205s: The psychology of aviation - Situational Awareness

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PSY205s The psychology of aviation -
Situational Awareness
Dave Nunez, MPhil Department of
Psychology University of Cape Town
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Admin info

• I am in room 4.22 (?650 4606)
• Paper Endsley 1999 from Work Return Room
• Slides for the time being
• http//www.cs.uct.ac.za/dnunez/teaching
• (on the course web page later)

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Why study aviation in psychology?

• Airplanes get more complex.

• .but the people who fly them remain the same.

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Why study aviation in psychology?
How safe is flying? Deaths per year by
cause (USA 1981-1994) Commercial
flight 100 Electrical current 850 Bicycle
riding 1000 Pedestrian 8000 Falling 12000 A
uto accidents 46000 So flying to Joburg should
be about 460 times safer than driving there.

• Goal Increase safety (purely applied)
• Aviation is a potentially dangerous activity
• Increase safety by engineering (better engines,
  etc)
• What about the people doing the flying?

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A little history

• During the psychometrics boom (1920s-1930s),
  psychologists get involved
• Pilot selection tests
• During WW2, psychologists begin to look at
  aviation loses
• More aircraft lost to accidents than the enemy!
• Bartlett, Chapanis, Craik, Gibson and other big
  names got involved

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Pilot error vs. Human error

• General rule was If the plane didnt fail, it
  was pilot error
• Pejorative phrase laid blame
• Implication not good enough
• Evidence from Chapanis and others showed it was
  actually human error
• Acknowledge limits of human beings
• Certain system features create situations where
  an error is more likely
• Problem becomes worse under certain environmental
  conditions

Alphonse Chapanis (1917-2002), was a leading
figure in the psychology of aviation safety since
the 1940s
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Example Human error (and a solution)

• Problem Pilots shut down engines in flight by
  pulling the wrong lever

Beechcraft Duchess (late 1970s)
Douglas DC-4 (early 1940s)

• Chapanis solution shape coding the lever
  handles (also color coded by function)

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Human Factors (Ergonomics)

• Understand patterns of errors
• Many errors can occur regardless of experience
• What about being human makes us likely to commit
  errors?
• Examine cognitive processes to identify danger
  spots
• Goal To create systems which reduce the
  probability of errors
• Pilot friendly aircraft which reduces errors
  and creates a better working environment

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A major contribution SA

• A recent important contribution Situational
  awareness
• Combination of mental models, working memory and
  situated cognition theory
• Tries to predict how and when errors can happen
• Applied to operation of complex systems (nuclear
  powerplants, ships, aircraft, cars)
• Much research, and is taught to pilots
• Increase their awareness of when things can go
  wrong

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A quick recap of the info-processing model

• Herbert Simons model
• Attention, WM (STM), LTM.
• Attention filters irrelevant (unexpected) stimuli
  out
• Stimuli are transformed in WM according to active
  rules and schema (from LTM)
• Contents of WM in turn activate rules and schema
  as required by the data
• Behaviour/consciousness is based on the contents
  of WM and active scripts

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SA definition

• the perception of the elements in the
  environment within a volume of time and space,
  the comprehension of their meaning and the
  projection of their status in the near future
  (Endsley 1998)
• Cognitive task (probably expertise bound)
• Dynamic (over time and space)
• Several levels of processing (perception,
  comprehension, prediction)

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Levels of SA (1)

• Level 1 Perception of the environment
• Other aircraft, terrain, own aircraft systems,
  navigation, radios
• Deals with the present loads perceptual
  buffers, attention and working memory

Mica Endsley (of SA Technologies, previously of
MIT) is one of the leading experts on situational
awareness in aviation
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Levels of SA (2)

• Level 2 Comprehension
• Synthesis of disjoint level 1 elements (big
  picture)
• Assign importance to each element (goal-directed)
• Forms a holistic understanding of what is
  happening now
• Reaching this level requires experience
• It is mostly a top-down task loads working
  memory, and requires LTM

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Levels of SA (3)

• Level 3 Projection (predicting)
• Requires both Level 1 and Level 2 SA
• Also expertise bound More experienced pilots
  spend more time predicting what will occur
• Effectively gives the pilot more time for
  decision making

The heavier an aircraft, the longer it takes to
respond to a pilots input. In such situations,
Level 3 SA is essential. This is partly why
airlines pick their most experienced pilots to
fly such aircraft.
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Cognition and SA levels

• All three levels require some WM and attention
• Level 1 Speech comprehension, decoding system
  interfaces attentional filtering (mostly
  bottom-up)
• Level 2 Activating mental models and schemata
  (mostly top-down)
• Level 3 Take LTM information and apply it to
  active models (mostly top-down)
• So WM and attention loads can be high during SA
• But Experts will use less (better chunking
  strategies, better at filtering out irrelevant
  elements)

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Information load Example
Data Sources Outside (terrain) Outside
(weather) Outside (aircraft) Inside
(gauges) Inside (maps) Inside (checklists) Inside
(crew) Aural (crew) Aural (control) Aural
(aircraft) Aural (alarms) Haptic
(controls) Haptic (buffets, etc)
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Individual factors in SA (1)

• Limits of attention
• Novices or experts in novel situations require
  more attention to be placed on the environment
• Information overload can exceed the capacity
  miss important relevant information
• Giving more attention to one SA task reduces it
  on another
• Serious problem NTSB review 31 of human
  errors due to problems acquiring relevant data

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Individual factors in SA (2)

• Can be overcome by sampling information
• Learn a way to scan the world (avoids fixation)
• Strongly trained patterns become habitual
• Sampling can fail
• Non-optimal strategy (focus on the wrong things)
• Visual dominance (forget other inputs)
• Memory failures (forget relative importance of
  elements)
• In overload, leave out certain elements

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Individual factors in SA (3)

• Attention limits can be helped by expertise
• Top-down knowledge creates expectations, which
  can increase processing speed
• BUT if unexpected information occurs, more
  likely to make an error (superiority effects)
• WM is used mostly for integration and projection
  (Levels 2 3)
• If much new info is being processed, little WM
  will be left for integration (and vice-versa!)
• Projection places a particularly heavy load on WM
  (need to store multiple states)

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Coping mechanisms (1)

• All is not lost cognitive strategies/structures
  exist to deal with this
• coping mechanisms (not really)
• Normal info sorting/learning structures
• Generally use previous knowledge to order the
  world
• Some trained (automaticity) some developed
  (mental models)
• Generally automatic, subconcious processes

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Coping mechanisms (2)

• Structured knowledge from experience (LTM)
• Schemata, scripts mental models
• fill in missing info (default values)
• Help with structuring comprehension (reduce WM
  attention used)
• Increase accuracy of predicting the future
• Can be a fuzzy fit
• Almost essential for higher levels of SA

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Coping mechanisms (3)

• Goal-driven processing
• Goals determine how resources are allocated also
• Goals provide a structure in which to process
  (allows higher levels of SA)
• Automaticity (habitual responses) scripted
• Allows processing with minimal attention
• Can miss novel stimuli
• Safe for routine situations (is there such a
  thing?)

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Putting it all together (Endsley 1995)
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Where the problems can occur
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Factors which reduce SA Stress (1)

• Physical stressors
• Noise, vibration, lighting, temperature, fatigue,
  jet lag
• Social/psychological stressors
• Anxiety/fear, uncertainty, self-esteem, career
  advancement, time pressure
• Stress effects are complex a little can help
  (yerkes-dodson law)

Stress produces many physical and psychological
effects which can reduce SA and undermine a
pilots ability to act correctly.
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Factors which reduce SA Stress (2)

• Why does stress affect SA?
• Attentional narrowing (high arousal/anxiety)
• Oversampling of dominant cues
• Scan patterns disrupted
• Premature closure (hasty decisions)
• Reduction in WM capacity / LTM retrieval (affects
  Level 2 3 most)
• Training reduces these effects
• Automaticity reduces attention and WM
  requirements
• More cues, better associations improve retrieval

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Factors which reduce SA under/overload

• Mental overload
• WM and attention limits reached
• Incomplete/erroneous perception
• Stressor (being behind the plane)
• Mental underload
• No active search for info
• Low vigilance/motivation

Air traffic controllers (ATCs) also require high
levels of SA. In busy sectors (such as London,
Atlanta or Tokyo) the volume of traffic can lead
to mental overload.
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Factors which reduce SA bad systems

• The aircrafts interface can present information
  poorly
• Presenting too much can lead to overload
• Hiding too much can lead to unawareness
• The layout of information can interfere with the
  scan
• Recently Smart planes (glass cockpit)
• Aware of the information required in a flight
  phase
• Show what is necessary, but watch for problems in
  the background
• Alert the crew if a problem exists (speech,
  icons, etc)

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Improvements in interfaces
Boeing 737-200Adv (late 1960s)
Boeing 737-800 (Early 2000s)
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Factors which reduce SA - Complexity

• Aircraft keep getting more complex
• Technology demands
• Increases workload more system components, more
  interactions
• Effectively increases number of goals and tasks
• An expert in these systems will be protected (a
  little)
• Pilots vary widely on their self-reported
  understanding of the systems
• A difficult road to becoming an expert!

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Factors which reduce SA Automation (1)

• Habitual procedures can take crews out of the
  loop
• Reduce vigilance, increase complacency
• Become a passive recipient of information
• Automatic states have bad cognitive consequences
• Pilots are slower to detect problems
• Slower to re-orient after realizing the problem
  (schemata de-activation/re-activation)

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Factors which reduce SA Automation (2)

• But automation can help SA also
• Computers can monitor many variables
• Remove unnecessary manual work (navigation)
• Can present many variables already integrated
  (for Level 2)
• The trick is create systems which aid but do not
  promote complacency

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How serious is a failure in SA?

• Jones Endsley looked at accidents in the USA
  over a 4 year period (major carriers)
• 77 had a substantial human error component
• Of those, 88 due to a failure of SA
• SA failures not even distributed among levels
• Level 1 72
• Level 2 22
• Level 3 6

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Further specific cause
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Teamwork SA in CRM

• Most aircraft are flown by a team
• Do other people increase or decrease SA?
• Spread the work Effectively have more WM and
  attention
• But Is that enough for collaboration?

Can too many cooks spoil this broth?
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Sharing data

• To work together, people must share info
• Keep mental models etc. aligned
• Each must know what information the other needs
• Must also share higher level understanding, and
  projection (level 2 and 3)
• Essential shared mental models
• High functioning crews communicate less than low
  functioning crews