Human Factors, Vigilance

and Cognitive Fatigue in

24/7 Security Operations 11 Oct 2011

James C. Miller, Ph.D., CPE millergonomics@yahoo.com

Air Force Research Laboratory (Retired),

Miller Ergonomics &

Oak Ridge National Laboratory

Fatigue Effects and Countermeasures in

24/7 Security Operations

Available from:

http://www.asisonline.or

g/foundation/noframe/

research/crisp.html

3

The International Ergonomics

Association (IEA) • The federation of ergonomics and human factors societies

around the world.

• In the U.S., the Human Factors and Ergonomics Society

(HFES) is both international in membership and a member of

the IEA

4

Human Factors and Ergonomics

Society (HFES) • Membership more than 4500; more than 50 active

chapters; technical groups now number 23.

5

Human Factors and Ergonomics

Society (HFES) HFES publishes:

• The journal, Human Factors

• The news publication, HFES Bulletin

• The Proceedings of the HFES Annual Meeting

• Ergonomics in Design, a magazine describing applications of

human factors research

• The Journal of Cognitive Engineering and Decision Making

• Reviews of Human Factors and Ergonomics

• Monographs on selected topics

• The American National Standard for Human Factors Engineering of

Visual Display Terminal Workstations (1992), updated as Human

Factors Engineering of Computer Workstations (2002)

6

Human Factors in Homeland

Security • Committee on Science and Technology for Countering

Terrorism, National Research Council. (2002). Making the

Nation Safer:The Role of Science and Technology in

Countering Terrorism. Washington, D.C.: The National

Academies Press.

• ―TSA should collaborate with the

public and private sectors to build a

strong foundation of research on

human factors and transportation

operations and to make the

evaluation of security system

concepts a central element of its

collaborative research program.‖ (p.

234)

7

DHS

Science & Technology Directorate, Human Factors/Behavioral

Sciences Division

TSA Human Factors/Behavioral Sciences

8

PNL

Pacific Northwest National Laboratory (Battelle):

• Violent Intent Modeling (VIM) system: software framework

to assist analysts in assessing the likelihood of groups to

engage in violent behavior

• Moved to the Institute for Homeland Security Systems (IHSS)

as Violent Intent Modeling and Simulation (VIMS) in 2008

(research consortium in Research Triangle Park NC)

VIMS

10

Information Security

• Human Factors in Information Security:

http://www.humanfactorsinsecurity.com/

• Data security breaches have surfaced with increased

regularity over the past years

• Financial losses due to cybercrime continue to grow

• Simple human error, ignorance or omission are nearly

always at the root of many of these data breaches and e-

crimes; in nearly every case there was no technical defense

that would have prevented them

• IT systems at all levels and within most organizations remain

inherently vulnerable to even the most basic of security and

fraud weaknesses and vulnerabilities

11

Information Security

• This is because we have focused almost entirely on the

technology; we have not attended in any way to the most

fragile element – our people.

• We must ensure effective communication and understanding

of what is required of them in their everyday behavior to

handle information in all its forms in a safe and secure manner

• Unless we do this, our data security and e-crime defenses will

never be complete.

12

Information Security

• Gary Hinson, ―Human factors in information security,‖

http://www.noticebored.com/html/human_factors.html:

• ―Computers alone don’t implement information security

policies and standards - human beings purchase and

configure the systems, switch on the control functions, monitor

the alarms and run them. Whatever way you look at the

problem, it is just as important to invest in your people as

your technology.‖

13

The Human Component

Overview:

• Two main strengths: more powerful pattern recognition

capabilities and better decision-making skills than can be

provided by automation

• Main weakness: greater performance variability than one

finds in software and modern hardware

14

The Human Component

• Assuming adequate training and currency in system

operation, the greatest contributor to that variability is

cognitive fatigue.

• Cognitive fatigue impairs, mainly, the operator’s monitoring

of sensor displays, execution of complex system control

functions, and interactions with automation.

• The monitoring of sensor displays requires the operator to

remain ―vigilant.‖

15

Vigilance Research

16

Vigilance Performance

• Definition: A monitoring task requires sustained vigilance

over long periods under boring and tedious conditions,

awaiting signals that have a low probability of occurrence but

which, when they do occur, are extremely important to system

performance or safety (Miller & Mackie, 1980).

• In any critical monitoring environment, a slip of attention may

have dire if not fatal consequences.

• Examples follow...

17

Vigilance Performance

Sonar & radar operators

TSA scanner

Detection of suspicious

behaviors embedded in

banks of video surveillance

monitors

Military surveillance

Air traffic control

Cockpit instrument monitoring

Seaboard navigation

Industrial process

control/quality control

Long-distance driving

Agricultural inspection

Cytological screening

(radiology)

Electrocardiogram monitoring

in ICU

Anesthesia monitoring during

surgery

Ironically, while these kinds of systems are being monitored they contribute to

the cognitive decrement that is causing their own compromise.

18

Vigilance Research

• Norman Mackworth's Clock Test was used to establish one of

the fundamental findings in the vigilance and sustained

attention research literature: the vigilance decrement, that is,

signal detection accuracy decreases notably after 30 minutes

on task.

• Seminal paper: Mackworth, N. H. (1948). The breakdown of

vigilance durning prolonged visual search. Quarterly Journal

of Experimental Psychology, 1(1), 6.

19

Vigilance Research The first depiction of the vigilance decrement (Mackworth, 1948)

The causes of the decrement have been debated ever since.

20

Vigilance Research

Much vigilance research in the 1970s, summarized here:

• Mackie, R. R. (1977). Vigilance:Theory, Operational

Performance, and Physiological Correlates. Springer.

• Miller, J. C., & Mackie, R. R. (1980). Vigilance Research and

Nuclear Security: Critical Review and Potential Applications

to Security Guard Performance, Goleta CA: Human Factors

Research Inc. Technical Report No. 2722. National Bureau of

Standards contract NBS-GCR-80-201 for the Defense Nuclear Agency;

available from the Electronics and Electrical Engineering Laboratory, Office

of Law Enforcement Standards, National Institute of Standards and

Technology, www.nist.gov/eeel/

21

Vigilance Research

• Robert Wilkinson developed a somewhat simpler test of

―arousal‖ and ―continuous, concentrated attention,‖ the

unprepared simple reaction time test (USRT).

• Seven previous studies led Wilkinson to develop a portable

testing device for the USRT: Wilkinson, R. T., & Houghton, D.

(1982). Field test of arousal: a portable reaction timer with

data storage. Human Factors, 24(4), 487-493.

• The device was based upon a cassette tape recorder. The

recommended test length was ten minutes.

22

Vigilance Research

The portable USRT (Wilkinson & Houghton, 1982).

23

Vigilance Research • Dr. David Dinges then

introduced a solid-state

version of the USRT called

the Psychomotor Vigilance

Task (PVT)

• Dinges, D. F., & Powell, J. W.

(1985). Microcomputer

analyses of performance on a

portable simple visual RT

task during sustained

operations. Behavior

Research Methods,

Instruments & Computers,

17(6), 652-655.

• Used extensively

24

Vigilance Research Both USRT devices produce similar data.

PVT Speed

Actual Sleep Times - Revised Model

Chronic Restriction Adaptation

50

65

80

95

110

0 T1 T2 B E1 E2 E3 E4 E5 E6 E7 R1 R2 R3

Day

Mea

n S

pe

ed

(as a

% o

f B

aselin

e)

9 Hr

7 Hr

5 Hr

3 Hr

SAFTE/FAST

R2 = 0.94

25

Vigilance Research

• However, note that the USRT/PVT has a signal probability of

1.0, much unlike many classic vigilance tests that have signal

probabilities of 0.02 to 0.03 (Miller & Mackie, 1980) or the

Clock Test that had a signal probability of 0.0067 (Mackworth,

1948).

• While the USRT/PVT is sensitive to fatigue, it is difficult to

classify it as a ―vigilance‖ task because it is such a short task

(10 min) and its signals are not embedded in a background of

high-frequency, un-meaningful events.

• Thus, though the USRT/PVT addresses some aspects of

sustained attention, and does capture errors of omission

(lapses), it fails to address the visual search component of

vigilance in security operations.

26

Vigilance Performance

Summary:

• Sustained attention on simple laboratory tasks wanes rapidly:

perhaps, as quickly as 20 minutes.

• Over time, error rates increase in terms of lapses:

extraordinary delays in detecting critical signals or complete

failures to detect.

• Individual vigilance performance, itself, becomes more and

more variable over time within and across subjects.

• Observers become progressively less efficient at detecting

either visual or auditory signals as the task continues.

• This is a task-specific fatigue that is caused when a console

operator is forced to remain vigilant in a task that is tedious,

detailed, and repetitive.

27

Vigilance Performance

Other influences on vigilance performance:

• Signal complexity, signal duration, environmental stressors,

monitoring load, social influences, personality traits, use of

drugs, sleep disruption, arousal, scheduling, health,

motivation, performance feedback (Miller & Mackie, 1980).

• Adverse environmental conditions, low motivation associated

with lack of performance feedback (Parasuraman, 1986).

• Fatigue, distraction, boredom, task environment, and outside

stressors (Mackie, 1977).

28

Vigilance Performance

Improving vigilance performance:

• The more involved the operator is in decision-making and the

more feedback the operator receives, the more aroused and

alert (vigilant) the operator may be (Schroeder et al., 1994)

29

Vigilance Performance

Recent view (Warm et al, 2008):

• Experiments comparing performance on successive vs.

simultaneous vigilance tasks support an attentional resource

theory of vigilance.

• Subjective reports also show that the workload of vigilance is

high and sensitive to factors that increase processing

demands

30

Vigilance Performance

Recent view (Warm et al, 2008):

• Neuroimaging studies using transcranial Doppler sonography

provide strong, independent evidence for resource changes

linked to performance decrement in vigilance tasks.

• Finally, physiological and subjective reports confirm that

vigilance tasks reduce task engagement and increase distress

and that these changes rise with increased task difficulty.

• Conclusion: converging evidence shows that vigilance

requires hard mental work and is stressful.

31

Vigilance Performance

Relevance:

• Vigilance is a critical component of performance efficiency in

airport baggage inspection and detection of illicit radioactive

materials at border crossings and ports.

32

Vigilance Performance

Relevance:

• Security guards and intelligence analysts may see but one

reportable threat in hours upon hours of search across

multiple unimportant events.

• When they report a threat, they actually may not have

witnessed a threat or they may have identified an event

incorrectly because threats and non-threatening events are

often quite similar. These are errors of commission.

33

Vigilance Performance

Relevance:

• The other type of error seen commonly is an error of

omission, in which a person fails to identify or notice a

threat when it is presented.

34

Vigilance Performance

Relevance:

• Several errors may occur simultaneously or in sequence,

a problem that, sometimes, makes the prediction of the

time course of the vigilance decrement complex

(Parasuraman, 1986).

35

Myths Busted

• The performance of a human operator in a system cannot be

measured objectively

• Humans are good at ―standing watch‖

• False: human vigilance performance has been measured

objectively across hundreds of investigations, and the human

operator has been found to be poor at standing watch in some

situations.

• The likelihood of errors due to changes in perceptual

threshold and/or perceptual sensitivity may be quantified in

terms of the Receiver Operating Characteristic (ROC)

36

Sleep Physiology and Fatigue

37

Cognitive Fatigue

• In any human-machine system, the most variable (unpredictable) component in the system is the human operator

• After training and currency, the greatest contributor to that variability is cognitive fatigue

• The flavors of cognitive fatigue are circadian, acute, cumulative, and chronic

• Fatigue is ubiquitous, pervasive and insidious

• Generally, the primary source of cognitive fatigue is inadequate sleep …

38

Neuroanatomy of Sleep

39

Electroencephalogram (EEG)

40

41

States and Stages When we are awake, we may be in one of two different states:

• A relaxed mental state (alpha waves), or

• An alert mental state (beta waves)

42

States and Stages When we are asleep, we may enter into one of two different

states:

• Non-REM Sleep includes Stages 1 to 4; may involve

dreaming

– Stage 1: Mostly theta waves

– Stage 2: Sleep spindles and K-complex waves

– Stage 3: Mostly delta waves

– Stage 4: Delta waves; difficult to awaken

• Or…

43

States and Stages • REM (Rapid Eye Movement) Sleep (= "paradoxical"

sleep)

– Brain waves somewhat similar to awake state or

Stage 1 sleep (low-voltage, mixed/fast waves)

– Rapid eye movements

– Almost complete loss of muscle control ("atonia")

– Penile erections (males) & vaginal moistening

(females)

– Easy to awaken

– Usually a time of more intensive, vivid dreams

44

45

Credit

Thanks to the web site for Psychology 340 at Le Moyne

College for all of the preceding sleep and arousal slides.

Fr. Vincent W. Hevern, SJ, Ph.D., Instructor

46

Sleep • Myth busted: Sleep is a passive or vegetative state.

• In fact, sleep is a complex neurophysiological state that is

generated by the interactions of at least three extensive

systems in the brain (arousal, slow-wave, REM)

• Sleep may be prevented or disrupted easily by poor sleep

hygiene, alcohol use, caffeine abuse, energy drinks, and

prescription and OTC medications

47

Sleep Disorders

48

Sleep Disorders

• Insomnia. Not sleeping enough due to (1) difficulty falling

asleep (onset insomnia), (2) frequent awakening during sleep

(maintenance insomnia), or (3) waking up too early

(termination insomnia)

• Sleep Apnea. Intermittent stopping of breathing during sleep

• Narcolepsy. Frequent, unexpected periods of sleep or

sleepiness during the day

49

Sleep Disorders

• Periodic Limb Movement. During non-REM sleep, individual

moves legs and sometimes arms every 20-30 seconds for

minutes or hours

• REM Behavior. During REM sleep, individual moves

vigorously or violently (kick, punch, etc.); dreams of violent

nature; occurs mostly in older men with brain diseases,

especially Parkinson’s Disease.

• Night Terrors. An intense anxiety from which one wakes up

screaming in terror

• Sleep Talking. We all do it.

• Sleepwalking. Usually in children 2-5 years old; harmless;

no danger to wake up the sleepwalking person

50

Sleep Disorders

Shift Work Sleep Disorder (SWSD)

• International Classification of Sleep Disorders (ICSD),

American Academy of Sleep Medicine (AASM;

www.aasmnet.org)

• Code 307.45-1, a circadian sleep disorder

• Essential features: ―symptoms of insomnia or excessive

sleepiness that occur as transient phenomena in relation to

work schedules.‖

51

Napping • The research and solo-sailor practice of Dr. Claudio Stampi

indicates that ―Sleep-deprived humans are better off snoozing

like most animals—in brief, precisely timed naps.‖

(T. Zimmerman)

• ―Under less-structured environments multiple naps do occur

throughout the 24 hr, and many subjects exhibit polyphasic

sleep similar to that observed in nonhuman species. … their

striking regularity allowed speculation on the existence of an

ultradian 4-hr component of the sleep-wake cycle that may be

superimposed on the more robust circadian and midafternoon

components.‖ (Stampi & Broughton, Why We Nap, 1990)

52

Napping • The structure of naps is dependent upon:

– The length of prior wakefulness for non-REM sleep

– 24-, 12- and 4-hour rhythms for REM sleep

• Because we cannot predict reliably what sleep stage will

occur in any given nap, and because all sleep stages appear

to be important for well-being, we do not prescribe limits on

nap lengths. Instead, we just advise operators with limited

sleep opportunities that

―Any sleep is good.‖

53

Circadian Rhythms

54

Circadian Rhythms • Circa (about) dian (daily)

– Physiological day is slightly more than 24 hours long

• A circadian clock in the brain coordinates daily physiological

cycles (suprachiasmatic nucleus of the hypothalamus; SCN;

―body clock‖)

– Sleep-wake cycle

– Body temperature cycle

– Digestive cycle

– Hormonal cycles

55

Circadian Rhythms • The SCN is synchronized daily by cues (Zeitgebers; time

givers) in the environment: mainly by daylight-darkness cycle,

weakly by social schedules and meals

• Body rhythms persist even in the absence of these external

time cues

• The SCN pacemaker cannot reset immediately to:

– Rapid time zone changes (> 1 hr/day; jet lag)

– Inverted work/rest schedules (shift lag)

• When circadian rhythms are disrupted, cognitive performance

is impaired and a feeling of malaise occurs until they are

realigned

56

Circadian Rhythms • Jet/shift lag symptoms include:

– Insomnia

– Awakening too soon

– Excessive daytime sleepiness (EDS)

– Impaired physical and mental performance

– Gastro-intestinal problems

• Acclimatization rate depends upon:

– Different body rhythms adapt at different rates

– Differences between people

– Age

– Direction of travel: usually faster after westward than eastward travel

57

Circasemidian Rhythm • Circadian rhythms in many measures of performance and

physiological activity have a 2-peak daily pattern caused by

a rhythm that has two cycles per day

– Circasemidian: circa—about, semi—half, dia—day

• No evidence exists to support the presence of a circasemidian

rhythm in the rhythmic cells of the suprachiasmatic nucleus.

• Relevant behavioral and physiological observations support

the need to consider this 12-h rhythmicity in the quantification

of daily variations in physiological function and some kinds of

cognitive performance.

58

Circasemidian Rhythm • Usually serves to (1) elevate the pre-dawn peak in mishaps,

• (2) create a secondary peak in the early afternoon in mishaps (the

"post-lunch dip"), and

• (3) depress the

late-morning

and early-

evening

troughs in

mishaps.

• Thus, the ―two-

peak daily

pattern of

mishaps.‖

59

Sleep, Fatigue & Performance

60

Fatigue Symptoms

61

Fatigue Symptoms

My eyes close and stay shut for too many seconds at a time.

No mental effort I exert can hold them open.

I’ve lost command over their muscles…

I’ve got to find some way to keep alert.

There’s no alternative but death and failure.

- Charles A. Lindbergh

The Spirit of St Louis

62

Fatigue Definitions

PHYSICAL FATIGUE

• The individual’s diminished physical capability is due to

overexertion (time or relative load).

• The effects of prolonged physical activity, or the effects of

brief but relatively extreme physical activity, either of which

taxes a person’s physical endurance or strength beyond the

individual’s normal limits.

63

Fatigue Definitions

TASK-SPECIFIC FATIGUE

• Repeated, demanding work causes fatigue and the need for

recovery.

• Work that is assisted by automation generally places

demands upon specific, fine-motor and visual functions. Some

of the work requires vigilance, and some requires repetitive

operations.

• Thus, we observe task-specific fine-motor muscular fatigue,

visual fatigue, vigilance failures, monotony, and repetitive-

stress injuries in the automated workplace.

• Each of these problems requires task-specific, short-term and

long-term fatigue management and recovery considerations.

64

Fatigue Definitions

TASK-SPECIFIC FATIGUE

• Some argue that task-specific fatigue is actually habituation;

others argue it is simply boredom.

• The fact is that task performance declines across time.

• This is the same overall pattern that we have with

wakefulness: performance declines as time awake continues.

• Task-specific fatigue and fatigue due to inadequate sleep may

be additive.

65

Fatigue Definitions

TASK-SPECIFIC FATIGUE

• If the individual cannot change tasks, then the effects of task-

specific fatigue may be difficult to avoid.

• The manager should provide ―a meaningful variety or mix of

tasks so as to avoid boredom and performance decrement‖

(Murphy et al., 1968).

• Some system operators do not suffer very much from task-

specific fatigue when they are in the control loop, i.e., ―hands-

on.‖ But they may suffer from sleepiness.

66

Fatigue Definitions

TASK-SPECIFIC FATIGUE

• Operators who monitor automated systems often fall prey to

vigilance decrements, boredom, habituation, and/or task-

specific fatigue.

• With respect to the interactions between acute fatigue and

task-specific fatigue, ―fatigue disrupts matching of effort to

task demands, such that the fatigued [operator] fails to

regulate effort effectively when the task appears easy‖

(Desmond & Matthews, 1997).

• This finding supports the practice of treating the effects of

acute or cumulative fatigue and task-specific fatigue as

additive (Murphy et al., 1968).

67

Fatigue Definitions

CIRCADIAN RHYTHM EFFECTS

• The individual’s normal, 24-hour, rhythmic biological cycle

degrades task performance. This is caused by one or more

nights of work or rapid movement (faster than one time zone

per day) across more than 3 time zones. These effects are

referred to as ―shift lag‖ and ―jet lag,‖ respectively.

• Continuous time spent in the new time zone will lead to

acclimation, but more acclimation time is needed for more

time zones crossed. Acclimation to night work may never

occur.

68

Fatigue Definitions

ACUTE MENTAL FATIGUE

• The individual’s diminished mental capability is due to

prolonged wakefulness, usually more than 16 hours, that

occurs between two major sleep periods.

• This acute, or transient, performance decrement should be

eliminated after a regular sleep period.

69

Fatigue Definitions

CUMULATIVE MENTAL FATIGUE

• The individual’s diminished mental capability is due to

disturbed or shortened major sleep periods between two or

more successive major waking, duty or work periods.

• One major sleep period will not eliminate cumulative fatigue.

70

Fatigue Definitions

CHRONIC MENTAL FATIGUE

• The individual is exposed frequently during at least one month

to multiple periods of prolonged wakefulness, excessive work

hours, disturbed or shortened major sleep periods, unresolved

conflicts, or prolonged frustration.

• It is not eliminated by any number of sleep periods without

first removing the cause.

71

Fatigue Definitions

CHRONIC MENTAL FATIGUE

• An individual must display, concurrently, four or more of the

following symptoms: the desire to sleep, apathy, substantial

impairment in short-term memory or concentration; muscle

pain; multi-joint pain without swelling or redness; headaches

of a new type, pattern or severity; unrefreshing sleep; and

post-exertional malaise lasting for more than 24 hours. The

symptoms must have persisted or recurred for at least one

month.

72

Fatigue Countermeasures Sleep

Napping

Caffeine

Modafinil

Mishap Investigation

Shiftwork scheduling

Predictive Modeling

73

Sleep • The most effective countermeasure for fatigue is to do as

much as possible to prevent it from occurring in the first

place.

• The primary culprit for feeling fatigued is sleep loss.

• Thus, whatever can be done to encourage regular sleep and

prevent sleep loss (cumulative fatigue, sleep debt) should be

high on the list of countermeasures.

• The principal advantage of getting enough sleep is that it will

reduce on-the-job fatigue, thereby reducing the need for other

countermeasures.

• Good-quality, nocturnal sleep is a particularly effective

control for the three hazards, length of prior wakefulness,

amount of prior sleep, and physical exertion

74

Sleep How much sleep do we need?

• Eight (8) hours per 24 hours is the average sleep need.

– Half of any given group will need more than 8 hours to prevent cumulative fatigue due to sleep debt.

National Sleep Foundation: http://www.sleepfoundation.org

75

Sleep Hygiene A Healthy Mind in a Healthy Body

• Manage stress as much as possible. Keep things in perspective and focus on what’s important. If needed, use relaxation techniques.

• Stay fit. Physical fitness tends to reduce anxiety and insomnia. Even something as simple as brisk walking can have a positive effect, if done regularly.

• Stimulate your mind. Chronic television viewing is associated with poor sleeping. Spend time working, talking, doing chores and pursuing hobbies.

• Pay attention to healthy nutrition

• Stop smoking. Nicotine stimulates the brain and increases blood pressure and heart rate, disturbing your ability to get to sleep and remain asleep.

Good Sleep Behaviors

• Use a bedtime ritual. For example, read a good book to take your mind off the stresses of work. When you feel drowsy, turn off the light.

• Don’t watch the clock. Hide illuminated clocks from view. If needed, set a couple of alarms and arrange for a wake-up call.

• Dress appropriately. Use loose-fitting, soft garments that breathe, in the right weight for the temperature of the bedroom.

76

Sleep Hygiene A Good Sleep Environment

• Strive for quiet. Low level and consistent sound may be useful. Use soft earplugs.

• Strive for darkness. Use a blanket or towel to block a window or the edges of a door. Use an eyeshade.

• Set the room temperature to 65 degrees F (20 degrees C).

• Strive for a humidity level of 60-70%. Use a humidifier or dehumidifier. These devices may provide a soft hum of ―white noise‖ that can help mask other noises.

• Strive for security. Lock the door.

• Design a restful-appearing bedroom. Keep It clean and free of clutter.

Good Sleep Equipment

• Use bed sheets that are clean and comfortably soft.

• Use a pillow that allows a healthy sleep posture: on your side with the spine straight, or on your back.

Extracted from Miller JC, Controlling Pilot Error: Fatigue, McGraw-Hill, 2001.

77

Napping Taking a nap can reduce fatigue effects and increase alertness

during work and non-work periods.

A nap can be very effective as a short-term countermeasure against fatigue effects, and to compensate during a period when workers will need to remain awake for a long time (more than 17 hours).

Some other situations where napping would be appropriate are:

• Less than 8 hours sleep during the main sleep period

• Awake for 30 minutes or longer two or more times during the main sleep period

• During a long and/or nighttime work period

PREACH THAT ―ANY SLEEP IS GOOD!‖

78

Napping

• Naps should be limited to a time, place and duration that will not interfere with operations.

• It is important to recognize that when naps are needed because of reduced sleep opportunities, workers are at risk of being critically fatigued.

• Allow 30’ to 60’ for sleep inertia to clear before critical events.

79

Tactical Caffeine Use • When natural fatigue countermeasures are impossible,

caffeine is a very effective alternative.

• Studies have shown that caffeine significantly improves both alertness (measured by MWTs) and performance (measured by the PVT, etc.).

• Doses ranging from 200-600 mg are particularly effective in people who do not normally use caffeine.

80

Tactical Caffeine Use • OTC doses:

– 1 cup Maxwell House = 100 mg

– 1 Starbucks Tall = 250 mg

– 1 Starbucks Grande = 375 mg

– 1 Starbucks Vente = 550 mg

– 1 cup tea = 50 mg

– 1 Coke = 50 mg

– 1 Mountain Dew = 55 mg

– 2 Excedrin Xtra = 130 mg

– 1 Max NoDoze = 200 mg

Source: Dr. John Caldwell & Dr. Lynn Caldwell

81

Tactical Caffeine Use • Caffeine must be used judiciously. Habituation occurs when

we take in more than about 250 mg/day!

• The best tactical approach to caffeine use is to take it only

right before you need it!

82

Sleep Aids Caldwell et al, 2009:

• Temazepam (Restoril®): optimize 8-h sleep periods that are

out-of-phase with the body clock

• Zolpidem (Ambien®): optimal for sleep periods less than 8

hours

• Zaleplon (Sonata®): initiate short naps (1 to 2 h) during a

period of otherwise sustained wakefulness, or initiate early

sleep onset before very early start time the next morning

• New aids for sleep maintenance : extended-release zolpidem

(Ambien CR®) and eszopiclone (Lunesta®)

• New aid for sleep onset: Ramelteon (Rozerem®) targets

melatonin receptors

Paul et al. 2010:

• Melatonin at 4 p.m. as an aid for phase advance

83

Fatigue Mishap Investigation

A fatigue incident tracking method to be used across days,

weeks, and months:

• Define time blocks; e.g., 00-0:300, 03-06:00, etc.

• Record the number of the unit's operations (e.g., sorties)

per block

• Record the number of minor incidents per block; e.g.,

minor errors by maintenance, ATC, cockpit, aerial port,

weapons, etc.

• Record the number of these minor incidents caused, at

least in part, by fatigue...

84

Fatigue Mishap Factors

A. Length of prior wakefulness > 17 hrs

B. Amount of prior sleep for the preceding 24 h < 8 hrs

C. Time of day 0200h to 0600h

D. Sleep debt > 10 hrs

E. Time zone change - days in zone > 3

F. Estimated physical exertion across the work period of interest

Different versions of this list are being incorporated into

investigation tools by the NTSB and the FRA.

85

Stupid Schedules

―Stupid‖ work-rest schedules are those that that:

• Ignore the biology of the human component of the weapon system or organization, and

• Violate the guidance given by Napoleon Bonaparte in 1796 to his commanders: You must not needlessly fatigue the troops

These schedules are ―stupid‖ in conception and ―stupid‖ in their effects on worker capabilities. They tend to make the worker ―stupid.‖

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―Stupid‖

American Heritage Dictionary

• Slow to learn or understand; obtuse.

• Tending to make poor decisions or careless mistakes.

• Marked by a lack of intelligence or care; foolish or careless: a stupid mistake.

• Dazed, stunned, or stupefied.

Dictionary.com

• Lacking ordinary quickness and keenness of mind; dull.

• Characterized by or proceeding from mental dullness; foolish.

• In a state of stupor; stupefied: stupid from fatigue.

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Shiftwork Scheduling

• Use a principle-based approach to shiftwork scheduling that constrains the infinite number of possible schedules to those schedules that are simple, practical to implement, and least harmful to worker health, job performance, and attitude (Miller, 2006).

• There is no ―good‖ continuous, 24/7 shift work schedule: humans are not designed to work at night, therefore night work causes sleep loss and shift lag.

• In turn, these cause fatigue at work.

• Thus, even good-quality shift work scheduling cannot prevent sleep loss and shift lag.

• Instead, it should be viewed as an effort to minimize the negative consequences. This is good for the workers’ health, safety and satisfaction, and for productivity.

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Shiftwork Scheduling

• One of many components of a shiftwork schedule is the number of crews that rotate to meet the demand for 24/7, continuous operations.

• In regular, 24/7 operations, the number of crews used should be greater than the number of shifts per day, so that at least one crew is off each day, except in maritime operations (Miller, 2006).

• In a regular schedule, it is the number of crews (not shift length!) that defines the average yearly, weekly, and daily amounts of time worked by an individual.

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Shiftwork Scheduling

Average work demands in regular schedules for different numbers of crews and for weekday-only workers, in hours.

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Shiftwork Scheduling

Average hours worked per week as a function of the number of crews.

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Shiftwork Scheduling

• Miller, J. C. (2006). Fundamentals of Shiftwork Scheduling,

Technical Report 2006-0011. Brooks City-Base TX: Air Force

Research Laboratory.

• Available free from the Defense Technical Information Center

(www.dtic.mil) as ADA446688.

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Myth Busted

• Sleepiness and fatigue always occur, and nothing can be

done about it

• False: there are many fatigue countermeasures that may be

used singly or in combination

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Safety, Alertness, Fatigue, and

Task Effectiveness (SAFTE™)

Model (PowerPoint material courtesy of Dr. Steve Hursh)

Schematic of SAFTE™ Simulation Model Sleep, Activity, Fatigue and Task Effectiveness Model

COGNITIVE

EFFECTIVENESS

SLEEP “QUALITY”

FRAGMENTATION

SLEEP INTENSITY

SLEEP

REGULATION

SLEEP

RESERVOIR

SLEEP DEBT

FEEDBACK

LOOP

INERTIA

CIRCADIAN OSCILLATORS

SLEEP ACCUMULATION (Reservoir Fill)

PERFORMANCE USE (Reservoir Depletion)

DYNAMIC

PHASE

PERFORMANCE

MODULATION

12

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• Its homeostatic and circadian components allow SAFTE™ to

model acute fatigue, cumulative fatigue and interactive

circadian effects

– The sleep homeostat

• SAFTE™ does NOT model task-specific fatigue, chronic

fatigue or physical fatigue

Types of Fatigue Modeled

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Decline of Performance with Total Sleep Deprivation SAFTE™ Model (red line) Predicts the Average Results with Precision

Sleep & Performance Model vs Angus & Heslegrave (1985)Mean of Normalized Performance Measures

0

20

40

60

80

100

120

0 10 20 30 40 50 60

Hours of Sleep Deprivation

Eff

ec

tiv

en

es

s (

Pe

rce

nt)

Serial RT

Decode

Encode

Vigilance

Logical

Mean Data

SAFTE Prediction

Parameters:

Acrophase: 1900

Wake up at 0700 hrs

Awakening at 0700 hrs

19 43

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Walter Reed Restricted Sleep Study

SAFTE™ Model (red line) Predicts the Average Results

with Precision

PVT Speed

Actual Sleep Times - Revised Model

Chronic Restriction Adaptation

50

65

80

95

110

0 T1 T2 B E1 E2 E3 E4 E5 E6 E7 R1 R2 R3

Day

Mea

n S

pe

ed

(as a

% o

f B

aselin

e)

9 Hr

7 Hr

5 Hr

3 Hr

SAFTE/FAST

R2 = 0.94

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Fatigue Avoidance Scheduling Tool

(FAST™)

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FAST™

• Also, the funding has supported the development of the

Fatigue Avoidance Scheduling Tool (FAST™) software, the

Windows® implementation of SAFTE™

• FAST™ is a fatigue assessment tool based on the SAFTE™

model

• Developed for the US Air Force and US Army

• DOT/FRA has extended and enhanced the tool for

transportation applications

• DoD verification, validation and accreditation, and DOT field

validations/calibrations are underway

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FAST™ I/O

• Inputs

– Work schedule data

– Sleep and naps or use AutoSleep

– Sleeping environment: Excellent, Good, Moderate, Poor

– Methods: graphic, grid, tables, import file

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FAST™ I/O

• Outputs

– Graph of performance: Mean Cognitive Performance Effectiveness

– Population Variance

– Lapse Index

– Mission Timeline – especially for aviation applications

– Dashboard

Fatigue Indicators

Performance Indicators

– BAC Equivalence Scale

– Summary Tables

– Clipboard copy of graph and tables to Excel, Power Point, Word

Cognitive performance (%) Cursor for I/O ―Dashboard‖ Sleep (blue; model input) Work (red; captures data output) Daylight/darkness (gray) Circadian phase (thin red curve)

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FAST™ Dashboard

FAST allows quantitative estimates of risk factors.

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COMPARE TWO SHIFT SCHEDULES

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ACCIDENT ANALYSIS

FAID

• Similarly, FAID® is a different software tool designed to assist

in the assessment of risks associated with workplace fatigue

due to hours of work, inadequate sleep, and fatigue-related

hazards. The underlying scientifically-based assumptions

about sleep and circadian rhythms are the same assumptions

used in SAFTE/FAST.

• A FAID® Score is in effect a relative measure of the sleep

opportunity which is afforded by the work schedule.

As the FAID® Score increases, the relative sleep opportunity

with work pattern decreases.

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Myth Busted

• The performance of a human operator in a system cannot be

measured objectively

• False: fatigue effects can be measured objectively, and many

of them can be predicted quantitatively and with good

reliability.

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Fatigue and Security

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Fatigue and Security

Types of security-focused research from which to draw

information (Miller, CRISP report, 2011):

• Shiftwork and fatigue in police operations

• Shiftwork and fatigue in control room operations

Lessons:

• All shift and night workers tend to suffer from the same health,

sleep disturbance, and cognitive performance problems

• Thus, one may apply to security operations the results of

decades of research on night work and shift work effects in

non-police and non-security occupations to the management

and scheduling of security operations personnel.

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Fatigue and Security

Fatigue Risk Management Systems (FRMS)

• DoD Operational Risk Management (ORM)

• Organizational commitment

• Systems approach

• Management-labor partnership

• Evaluation

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Fatigue ORM

Use of the quantitative fatigue model, SAFTE, and well-accepted fatigue countermeasures in the formal DoD context of operational risk management (ORM): Miller & Eddy, 2008, DTIC ADA501985

Identification of Fatigue Hazards

• Used the known, primary physiological and psychological effects of fatigue.

• Aligned these effects approximately with cognitive and physiological tests shown to be sensitive to the fatigued state

• Extrapolated the listed effects to safety-sensitive jobs through examples

• Each effect had the potential to cause harm in military operations and, thus, was a hazard

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Fatigue ORM

Use of the quantitative fatigue model, SAFTE, and well-accepted fatigue countermeasures in the formal DoD context of operational risk management (ORM): Miller & Eddy, 2008, DTIC ADA501985

Assessment of Fatigue Risks

• Using SAFTE and other data, quantified the risks associated with the five types of fatigue:

– Physical fatigue

– Circadian effects

– Acute fatigue

– Cumulative fatigue

– Chronic fatigue

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Fatigue ORM

Use of the quantitative fatigue model, SAFTE, and well-accepted fatigue countermeasures in the formal DoD context of operational risk management (ORM): Miller & Eddy, 2008, DTIC ADA501985

Analysis of Fatigue Risk Control Measures

• The best fatigue countermeasure is sleep, which is the only countermeasure that provides recovery

• It also reduces the probability that fatigue will have an effect on mission safety and, concomitantly, reduces the exposure to fatigue

• When adequate sleep cannot be used to counter fatigue, then one must consider the use of ―Go‖ and ―No-go‖ adjuncts, including schedule adjustments and pharmacological adjuncts

• These adjuncts serve to reduce the severity of fatigue effects or the exposure to fatigue-related risk

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ORM

Use of the quantitative fatigue model, SAFTE, and well-accepted fatigue countermeasures in the formal DoD context of operational risk management (ORM): Miller & Eddy, 2008, DTIC ADA501985

Possible Fatigue Risk Control Decisions

• All controls except sleep should be viewed as ―band-aid‖ approaches, to be used as a last resort when other controls are insufficient and the mission must be accomplished

• Recovery sleep will still be necessary after the other controls have been applied to accomplish the mission.

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Fatigue and Security

Fatigue Risk Management Systems (FRMS) – Organizational

Commitment

• Initiated and sustained with a top-down management

approach.

• Integrated program that addresses the requirements of all

stakeholders.

• Foundation of commitment, cooperation, knowledge,

assessment, and program refinement at all levels of the

organization (McCallum et al., 2003).

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Fatigue and Security

Fatigue Risk Management Systems (FRMS) – Organizational

Commitment

• Allocation of resources sufficient for establishing and

sustaining a fatigue management program.

• Senior executives must be involved in the formulation and

support of their organization’s fatigue management policy.

• Program policy established through a joint effort by all

organizational stakeholders.

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Fatigue and Security

Fatigue Risk Management Systems (FRMS) – Systems

Approach (Moore-Ede, 1994)

• Re-evaluate human asset potential and priorities; a

fundamental shift in how human assets are viewed.

• Establish management commitment and support commitment

at all levels, starting at the top.

• Define the FRMS as an integral part of organizational

philosophy and mission; institutionalize the commitment that

people requirements have priority.

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Fatigue and Security

Fatigue Risk Management Systems (FRMS) – Systems

Approach (Moore-Ede, 1994)

• Assess current risks, liabilities, and hazardous exposures; get

input from the ―front-line troops.‖

• Launch appropriate change initiatives to reduce exposures

and capture performance-improvement opportunities.

• Educate and provide ongoing support and training for all

personnel.

• Report results and measure performance to plan.

• Translate into a continuous, institutionalized process for

improving overall productivity, quality, and safety

performance.

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Fatigue and Security

Fatigue Risk Management Systems (FRMS) – Management-

Labor Partnership

• A challenge for CEOs and their personnel to address fatigue

management from a common perspective.

• Work-rest schedules, affect both operational efficiency and

individual well being.

• The issues are critical to both the organization and the

workers: reducing on-the-job accidents, improving employee

health, improving operational efficiency.

• May serve as a basis for establishing more productive

relationships.

• An effective FRMS will involve both CEOs and their personnel

in supporting these common objectives.

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Fatigue and Security

Fatigue Risk Management Systems (FRMS) – Evaluation

• The FRMS requires periodic evaluation and refinement.

• Evaluation should be tied back to established objectives.

• Possible measures:

– Average number of sick days

– Numbers of accidents and incidents due to operator

fatigue

– Attendance at FRMS educational events

– Numbers of personnel completing confidential

fatigue-screening

– Responses to a periodic alertness management

survey

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Fatigue and Security

Fatigue Risk Management Systems (FRMS) – Evaluation

• Additional information about assessment methods and tools in

Chapter 5 of Miller, 2006.

• Program refinements close the gap between objectives and

evaluation findings.

• Successful refinement requires continued oversight and

improvement of the alertness management program.

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Conclusion

What we've covered:

• Myth Busting

• Human Factors and Ergonomics Research

• Vigilance Research

• Sleep Physiology and Fatigue

• Fatigue Countermeasures

• Fatigue and Security

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Myths Busted

• The performance of a human operator in a system can be

measured objectively

• Humans are not good at ―standing watch‖

• Sleep is a not passive, vegetative state; ―I can sleep when I

die‖ is an inappropriate view for a person who holds a safety-

sensitive job

• Sleepiness and fatigue always occur, but many things can be

done about them in security operations

Action Items

P.A. Hancock, G.P. Kreuger (2010). Hours of Boredom,

Moments of Terror. Temporal Desynchrony in Military and

Security Force Operations. National Defense University Center

for Technology and National Security Policy, Fort Lesley J.

McNair, Washington, DC.

http://www.ndu.edu/ctnsp/publications.htm

Action Items

Inadequate recognition of the implications resulting from long lull

periods, work pulses, and the need to recover from stress can

lead to dysfunction and poor individual and small group

performance.

Accounting for such time-based transitions in psychological state

is important in configuring resilience training for small group

leaders, their personnel, and their organizational units.

Action Items

How is this done?

• Recognize rhythms in human activity

• Spread out cognitive task demands: shift some cognitive load

to periods of quiescence

• Plan for adequate rest and sleep

• Train to anticipate both hours of boredom and moments of

terror

• Anticipate future technological assists in cognitive

assessment: manager/director/commander should have

some type of on-line assessment of the cognitive and

physiological state of readiness of the individuals under his or

her direction/command [available, but not used widely]

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Questions? millergonomics@yahoo.com