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Dr. Steve Kass Department of Psychology University of West Florida. Military Psychology: Human Factors. What is Human Factors?.
July 1988, USS Vincennes shot down Iranian civilian airliner killing 290 on board
February 2001, USS Greeneville accidentally sinks Japanese fishing boat killing 9 crewmembers (4 HS students)
Joint Combat Advanced Display and Debriefing System (JCADDS)
Human Factors application: Why use red lights in cockpits and darkrooms?
- because rods are insensitive to longer wavelengths (red) the eyes “think” they are in the dark already allowing user to dark adapt more quickly)
Tactile– Cutaneous or somatosensory sense provided by receptors just under the skin.
Types of Receptors:
Thermoreceptors– detect heat/cold
Mechanoreceptors– detect pressure
Nociceptors – detect noxious stimuli (causticsubstances)
Haptic– Shape information provided through manipulation of fingers
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.
Human factors application of haptic research
Vestibular System – detects acceleration forces, maintains upright posture/balance and controls eye position relative to head
Semicircular 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) – 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.
High G-force tolerances
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
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 cues
Somatogravic 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
3000 mHigh Altitude
Converts sound energy (outer ear) to mechanical energy (middle ear) to electrical nerve energy (inner ear), then sends signal to the brain
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