8. Human Sensory & Information Processing System

1. 8. Human Sensory & Information Processing System

2. Human Vision Functional physiology of human vision

3. 10^6 10^3 Radio 10^0 Micro 10^-3 Infrared 10^-6 Ultraviolet 10^-9 Gamma 10^-12 & X 10^-15 Cosmic Photometry Light is electromagnetic energy from 400-700 nm 700 (nm) (m) Red Yellow 600 Green 500 Cyan Blue 400

4. Photometric Terms • Radiance light energy at specific wavelengths • Luminance total perceived energy emitted from surface • Illuminance perceived energy falling on surface • Chrominance color of light

6. Human Hearing Sense • Frequency dependent • Always “on” • Subject to temporary loss of sensitivity • Subject to permanent, irrecoverable injury from noise over exposure

7. Noise Exposure Effects • Hearing loss: temporary and permanent • Performance decrements, esp. for cognitive tasks • Increased perceived stress levels • Hypertension, increased blood pressure

8. HIP Model (Wickens, 1984) Attentional Resources Short Term Sensory Store Perception Decision Making Response Execution Working Memory Long-Term Memory Memory Feedback

9. Perception • Detection—is a single/stimulus present • Identification—noting the characteristics of the signal stimuli • Recognition—determine type of signal

10. Signal Detection Theory • Describes Perception when • 2 states of a signal • noise is present • Signal Present Signal Absent • Yes • Hit False • Operators Alarm • Response • NO Miss Correct Rejection

11. Memory • 3 primary activities • encoding – transformation • Performing by working memory usually it is • Spatial encoding (pictures) • Verbal encoding (memory as sounds) • storage – holding—2 primary areas (working and long term) • retrieval -- locating and bringing to conscious awareness (increases in difficulty with age)

12. Decision Making • Evaluating Alternatives and selecting a course of action • What influences DM? Differences, experiences, and biases • Research findings help to describe the human decision making process • emphasis on early information • personal preferences will influence • limited capacity for analyzing options

13. Attention • Attention is the allocation of cognitive resources to perception • Selective—may monitor several channels to perform a single task to determine if an event has occurred (e.g. pilot, driver, etc.) • More channels to monitor decreases our performance • If signals primarily in a few channels, we will direct our efforts to those channels • Guidelines for Design of Tasks • Use few channels • Identify important channels for effective resource allocation • Reduce stress • Preview where signals will occur in the future • Train on effective scanning patterns • Place channels close together • Make auditory channels distinctly different from background noise • If responses are required, ensure there is ample time to respond

14. Mental Workload • No single measure can completely measure WL • Valid measures are used for: • Allocating functions and tasks between operators • Comparing equipment alterations with respect to WL • Monitor operators to change task difficulty or function allocation • Operator selection and assignment • Primary Task Measures • Major activities required of the operator • Secondary Task Measures • Spare resources are used to perform these tasks

15. Mental Workload • Physiological Measures • Evoked brain potentials • Pupillary response • Respiration rate • Body temperature • Subjective Measures • Questionnaires, surveys (most common NASA TLX, SWAT, Cooper Harper Scale)