Dr. Steve KassDr. Steve KassDepartment of PsychologyDepartment of PsychologyUniversity of West FloridaUniversity of West Florida

Military Psychology:Human Factors

What is Human Factors?What is Human Factors? The discovery and

application of information about human behavior, abilities, and other characteristics to the design of tools, machines, systems, tasks, jobs, and environments for productive, safe, comfortable, and effective human use.

Human Factors Psychology and Human Factors Psychology and Related DisciplinesRelated Disciplines

ErgonomicsHuman Factors EngineeringEngineering PsychologyHuman-Machine InteractionCognitive EngineeringIndustrial/Organizational Psychology

Scope of Human FactorsScope of Human Factors

History of Human FactorsHistory of Human FactorsEmerged during World War II

– Need for people to effectively operate sophisticated military systems

– Early emphasis was on productivity and physiology

After WWII the discipline continued to grow to meet the challenge of non-military problems– Emphasis shifted to include other objectives, such as safer and

healthier working environments and improvements in the quality of working life

– HF boosted by space program, computers, home technology

Role of Human FactorsRole of Human FactorsUser-Centered Design

– Systems designed to fit people (not vice-versa).– Reduces training time.– Minimizes human error.– Improves comfort, safety, and productivity.

HF Approaches to Problem-SolvingHF Approaches to Problem-Solving

Equipment Design – change physical equipment

Task Design – change how task is accomplished

Environmental Design – change features of the work environment such as temperature, lighting, sound

Training – change worker behavior by providing skills and teaching procedures

Human Factors Military ActivitiesHuman Factors Military Activities

Accident InvestigationSimulation, Virtual Reality, & TrainingEquipment/Task DesignBasic & Applied Research

Accident InvestigationAccident Investigation

February 2001, USS Greeneville accidentally sinks Japanese fishing boat killing 9 crewmembers (4 HS students)

July 1988, USS Vincennes shot down Iranian civilian airliner killing 290 on board

Simulation & TrainingSimulation & Training Submarine Training SimulatorsSubmarine Training Simulators

Military TrainingMilitary TrainingIntelligent Enemies (LG)Intelligent Enemies (LG)

Intelligent Enemies– Courses of action (COA) not

developed sequentially.– COA/eCOA assessed

simultaneously by LG zones.

Hypergames– Strategic, operational and

tactical considerations in one game.

– Hyperlinked at different resolutions for continuous real-time play.

Task/Equipment DesignTask/Equipment Design

Displays used for TrainingDisplays used for Training

Joint Combat Advanced Display and Debriefing System (JCADDS)

EnvironmentEnvironment• Heat/Cold• G-forces/Weightlessness• Altitude• Lighting• Noise/Vibration• Stress • Chemicals

Light & VisionLight & VisionDark AdaptationDark Adaptation

Human Factors application: Why use red lights in cockpits and darkrooms?

-Takes about 30 minutes to dark adapt, but just a few minutes to light adapt

- because rods are insensitive to longer wavelengths (red) the eyes “think” they are in the dark already allowing user to dark adapt more quickly)

Sense of Touch:Sense of Touch:Tactile and HapticTactile and Haptic

TactileTactile – Cutaneous or somatosensory sense provided by receptors just under the skin.

Types of Receptors:Thermoreceptors – detect heat/coldMechanoreceptors – detect pressureNociceptors – detect noxious stimuli (caustic

substances)HapticHaptic – Shape information provided through manipulation of fingers

Human factors application of haptic research

This device provides haptic information to aid in performing a tracking task. The user feels the button pop out and must move the stick in the same direction to maintain course.

Haptic RespondingHaptic Responding

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Error(degrees)

Simple Complex

Response Type by Stimulus Complexity InteractionF(1, 28) = 4.63, p < .05

Haptic

Verbal

Vestibular SystemVestibular SystemVestibular SystemVestibular System – detects acceleration forces, maintains upright posture/balance and controls eye position relative to head

Semicircular CanalsSemicircular Canals – detect angular acceleration (rotation) in 3 axes - a crista embedded in a jelly-like material (cupola) is supported by hair cells that bend and fire when the crista moves in response to head rotation.Vestibular Sacs (Utricle & Saccule)Vestibular Sacs (Utricle & Saccule) – detect linear acceleration - hair cells embedded in jelly-like substance lag behind when the head moves. When motion becomes steady, otoliths catch up and hairs no longer bent.

AccelerationAcceleration

High G-force tolerances• +/- 2 Gz – pressure on butt, drooping face, noticeable weight increase• +/- 3-4 Gz – Difficult to move, loss of fine motor movements, speech affected• + 5.5 Gz – Negative blood pressure -> GLOC or grayout (passengers may

blackout sooner)• Higher tolerances (>10) possible in Gx plane (forward acc) – weight on chest,

difficulty breathing

Prevention/Protection• G-suit – squeezes blood out of extremities – increases tolerance by 2 G• Active Straining Maneuver (Blue Angels) – Pull head down, slow forceful

breathing, tensing of muscles – increase tolerance by 1.5 G

Gz

Gy

Gx

Note: force of gravity ~9.8 m/sec2 or 33 ft/sec2, therefore 5 G would be roughly equivalent to going from 0 to 112 mph in one sec

Motion DisturbancesMotion Disturbances

Spatial Disorientation – vestibular illusion which tricks the brain into thinking body is a different position than it actually is.

Vection – the illusion of self-motion induced my visual cuesSomatogravic Illusion – acceleration creates illusion that plane is

nose-up, deceleration feels like the plane is nose-down

Motion Sickness – nausea, disorientation and fatigue attributed to disturbance of vestibular system caused when vision and inner ear send conflicting (decoupled) signals

Treatments – • Medications – Antihistamines (Dramamine), Dopamine blockers or anti-psychotics (Thorazine), anti-nausea (serotonin) and Scopolamine (anticholinergic)• Behavioral strategies – sit facing front with front window view, eat bland foods such as bread, bananas, rice. If on a boat, stay in middle (less rocking) and look forward at the horizon, not at the waves.

Sopite SyndromeSopite Syndrome

Sopite SyndromeSopite Syndrome – motion induced drowsiness• Subset of motion sickness symptoms, but sometimes the sole manifestation• Dangerous because victims often not aware of its onset or the likelihood of onset• Found to affect passengers and operators of cars, trucks, ships, helicopters, planes, and simulators• No known prevention techniques (many motion sickness medications increase drowsiness)• May be a major cause of accidents and military pilot pilot training washout

Heat StressHeat Stress Small fluctuations in body temp greatly impact physical &

cognitive performance Problems include:

– +/- 6° C of core body is fatal (normal ~ 37° C)– Dehydration, heat exhaustion, heat stroke– Effects on continuous, low arousal tasks (vigilance)– Aggravated by sweating (slippery hands, sweat in eyes, heated metal

equipment)– May create perceptual difficulties (e.g., mirages, visual distortion,

optical illusions)– Carrying heavy protective gear contributes to heat stress (gloves,

boots, body armor)

ColdCold

Injuries associated with cold: Hypothermia, Immersion foot, Frostbite

Performance effects include:– Loss of psychomotor/manual dexterity, shivering– Reduced tactile sensitivity

Countermeasures: dry, layered clothing, warm food/liquids, wind barriers, large muscle activity

High AltitudeHigh AltitudeAltitude Sickness

•Loss of aerobic capacity by 10% for every 1000m over 1500 m

•Neurasthenic Syndrome – fatigability, decreased motivation, psychosomatic symptoms + reduced visual ability

•Paranoia, O-C, depression, hostility, decreased cognitive functioning

•Cyclothymic Syndrome – alternating depression, elevated mood

•Acute Organic Brain Syndromes – structural & functional defects in the CNS

7000 m

5000 m

3000 m

Noise & Hearing LossNoise & Hearing Loss

Converts sound energy (outer ear) to mechanical energy (middle ear) to electrical nerve energy (inner ear), then sends signal to the brain

Decibel ScaleDecibel ScaleSource Intensity # Times > TOH

Jet at take-off; ear damage likely 140 dB 1014

Threshold of pain 130 dB 1013

Front row of a rock concert 110 dB 1011

Walkman at maximum volume 100 dB 1010

Vacuum cleaner 80 dB 108

Busy street 70 dB 107

Normal conversation 60 dB 106

Quiet office 40 dB 104

Whisper 20 dB 102

Normal breathing 10 dB 101

Threshold of hearing 0 dB 100

Sound intensity (dB) = 20 log (P1/P2); where P2 is the threshold of hearing

Note: M-16 rifle ~ 160 dB, M-198 Howitzer ~ 185 dB

Hearing LossHearing Loss

Dangers of excessive noise: Dangers of excessive noise: • Hearing loss – caused by exposure to loud noises. Some hearing loss is expected with age (higher freqs)

• Loss of sensitivity while noise is present • Temporary Threshold Shift (TTS) – Loss of hearing that lingers after noise is terminated (post-rock concert)

- Tinnitus or ringing in the ears- 100 dB for 100 min causes a 60 dB TTS

• Permanent Threshold Shift (PTS) – Occupational Deafness caused by long term exposure (esp high freqs)• Eardrum rupture ~ 184 dB