PSY205s: The psychology of aviation - Situational Awareness Dave Nunez, MPhil Department of...

PSY205s: The psychology of aviation -

Situational Awareness

Dave Nunez, MPhil

Department of PsychologyUniversity of Cape Town

2PSY205s – The psychology of aviation: Situational Awareness

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)


Why study aviation in psychology?

Airplanes get more complex….

Bleriot Model XI - 1909 Aerospatiale-BAC Concorde - 1969

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


Why study aviation in psychology?

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?

How safe is flying?

Deaths per year by cause(USA 1981-1994)

Commercial flight: 100Electrical current: 850Bicycle riding: 1000Pedestrian: 8000Falling: 12000Auto accidents: 46000

So flying to Joburg should be about 460 times safer than driving there.


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


Pilot error vs. Human error

General rule was: If the plane didn’t fail, it was “pilot error”

Pejorative phrase; laid blameImplication – ‘not good enough’

Evidence from Chapanis and others showed it was actually “human error”

Acknowledge limits of human beingsCertain system features create situations where an error is more likelyProblem becomes worse under certain environmental conditions

Alphonse Chapanis (1917-2002), was a leading figure in the

psychology of aviation safety since the 1940s


Example: Human error (and a solution)

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

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

Dou

glas

DC

-4 (

early

194

0s)

Bee

chcr

aft

Duc

hess

(la

te 1

970s

)


Human Factors (Ergonomics)

Understand patterns of errorsMany errors can occur regardless of experienceWhat 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


A major contribution: SA

A recent important contribution: Situational awareness

Combination of mental models, working memory and situated cognition theoryTries to predict how and when errors can happenApplied to operation of complex systems (nuclear powerplants, ships, aircraft, cars)

Much research, and is taught to pilotsIncrease their awareness of when things can go wrong


A quick recap of the info-processing model

[Herbert Simon’s model]Attention, WM (STM), LTM.Attention filters irrelevant (unexpected) stimuli outStimuli 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 dataBehaviour/consciousness is based on the contents of WM and active scripts


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)


Levels of SA (1)

Level 1: Perception of the environment

Other aircraft, terrain, own aircraft systems, navigation, radiosDeals 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


Levels of SA (2)

Level 2: ComprehensionSynthesis of disjoint level 1 elements (‘big picture’)Assign importance to each element (goal-directed)Forms a holistic understanding of what is happening nowReaching this level requires experienceIt is mostly a top-down task; loads working memory, and requires LTM


Levels of SA (3)

Level 3: Projection (predicting)

Requires both Level 1 and Level 2 SAAlso expertise bound – More experienced pilots spend more time predicting what will occurEffectively gives the pilot more time for decision making

The heavier an aircraft, the longer it takes to respond to a pilot’s input. In

such situations, Level 3 SA is essential. This is partly why airlines pick their most experienced pilots to

fly such aircraft.


Cognition and SA levels

All three levels require some WM and attentionLevel 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)


Information load: ExampleData 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)


Individual factors in SA (1)

Limits of attentionNovices or experts in novel situations require more attention to be placed on the environmentInformation 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



Can be overcome by ‘sampling’ informationLearn 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



Attention limits can be helped by expertiseTop-down knowledge creates expectations, which can increase processing speedBUT: 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)


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



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 futureCan be a ‘fuzzy fit’Almost essential for higher levels of SA



Goal-driven processingGoals determine how resources are allocated alsoGoals provide a structure in which to process (allows higher levels of SA)

Automaticity (habitual responses) – ‘scripted’Allows processing with minimal attentionCan miss novel stimuliSafe for routine situations (is there such a thing?)


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all

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(En

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19

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)


Wh

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th

e p

rob

lem

s ca

n o

ccu

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Factors which reduce SA – Stress (1)

Physical stressorsNoise, 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

pilot’s ability to act correctly.


Factors which reduce SA – Stress (2)

Why does stress affect SA?Attentional narrowing (high arousal/anxiety)Oversampling of dominant cuesScan patterns disruptedPremature closure (hasty decisions)Reduction in WM capacity / LTM retrieval (affects Level 2 & 3 most)

Training reduces these effectsAutomaticity reduces attention and WM requirementsMore cues, better associations improve retrieval


Factors which reduce SA – under/overload

Mental overloadWM and attention limits reachedIncomplete/erroneous perceptionStressor (being ‘behind the plane’)

Mental underloadNo active search for infoLow 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.


Factors which reduce SA – bad systems

The aircraft’s interface can present information poorly

Presenting too much can lead to overloadHiding too much can lead to unawarenessThe layout of information can interfere with the scan

Recently: ‘Smart’ planes (‘glass cockpit’)Aware of the information required in a flight phaseShow what is necessary, but watch for problems in the backgroundAlert the crew if a problem exists (speech, icons, etc)


Improvements in interfacesB

oein

g 73

7-20

0Adv

(la

te 1

960s

)

Boe

ing

737-

800

(Ear

ly 2

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)


Factors which reduce SA - Complexity

Aircraft keep getting more complexTechnology demandsIncreases workload – more system components, more interactionsEffectively 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 systemsA difficult road to becoming an expert!


Factors which reduce SA – Automation (1)

Habitual procedures can take crews ‘out of the loop’

Reduce vigilance, increase complacencyBecome a passive recipient of information

Automatic states have bad cognitive consequences

Pilots are slower to detect problemsSlower to re-orient after realizing the problem (schemata de-activation/re-activation)


Factors which reduce SA – Automation (2)

But: automation can help SA also

Computers can monitor many variablesRemove 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


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 componentOf those, 88% due to a failure of SA

SA failures not even distributed among levels

Level 1: 72%Level 2: 22%Level 3: 6%


Further: specific cause


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 attentionBut: Is that enough for collaboration?

Can too many cooks spoil this broth?


Sharing data

To work together, people must share infoKeep mental models etc. alignedEach must know what information the other needsMust also share higher level understanding, and projection (level 2 and 3)

Essential: shared mental modelsHigh functioning crews communicate less than low functioning crews

PSY205s: The psychology of aviation - Situational Awareness Dave Nunez, MPhil Department of...

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