History of HCI Human Capabilities

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History of HCIHuman Capabilities

• Key people, events and ideas
• Understanding the user

2
Agenda

• Human capabilities
• Senses
• Information processing
• Perceptual
• Cognitive
• Memory

3
Human Capabilities

• Want to improve user performance
• Know the user!
• Senses
• Information processing systems

4
Senses

• Sight, hearing, touch important for current HCI
• smell, taste ???

5
Sight

• Visual System workings
• Color - color blindness 8 males, 1
  females
• Much done by context grouping (words,
  optical illusions, )

6
Eyes

• Retina receives image
• Light sensitive cells
• Two types
• Rods
• Monochrome
• Sensitive to entire visible spectrum
• Small
• Fast-acting
• Distributed throughout Retina

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Eyes-Retina

• Retina Cells Cones
• Three types
• Red, Green, Blue
• Each type sensitive to limited range of visible
  light
• Cones are larger cells than rods
• Cones are less sensitive
• Strongly concentrated in Fovea
• Relatively few cones outside fovea

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Fovea

• High-resolution area of Retina
• Its what you point your eyes at to get good
  image
• About 2 degrees visual angle
• Densely packed with Rods Cones

9
Hearing

• Often taken for granted how good it is
• Pitch - frequency
• Loudness - amplitude
• Timbre - type of sound (instrument)
• Sensitive to range 20Hz - 22000Hz
• Limited spatially, good temporal performance

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Hearing

• Sounds can be perceived as coming from a location
• Not terribly accurate
• Cone of confusion

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3D Audio Perception

• Cone of confusion
• Cone-shaped zones in front of and behind head
• 3D Audio cues
• Interaural Time Difference
• Interaural Intensity Difference
• Pinnae filtering
• Body filtering

12
Touch

• Three main sensations handled by different types
  of receptors
• Pressure (normal)
• Intense pressure (heat/pain)
• Temperature (hot/cold)
• Where important?

13
Models of Human Performance

• Predictive
• Quantitative
• Time to perform
• Time to learn
• Number and type of errors
• Time to recover from errors
• Approximations

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Basic HCI

• Model Human Processor
• A simple model of human cognition
• Card, Moran, Newell 1983
• Components
• Senses
• Sensory store
• Short-term memory
• Long-term memory
• Cognition

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Model Human Processor Basics

• Based on Empirical Data
• Three interacting subsystems
• Perceptual (eg. read-scan)
• Cognitive (eg. think)
• Motor (eg. respond)

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Information Processing

• Usually serial action
• Respond to buzzer by pressing button
• Usually parallel recognition
• Driving, reading signs, listening to radio

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Model Human Processor Basics

• Parameters
• Processors cycle time of 50-200ms
• Memories have type, capacity, decay time
• Types
• Visual
• Auditory
• Tactile
• Taste, smell, proprioception, etc

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Model picture
19
Model Picture Closeup
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Perceptual Processor

• Continuously grabs data from the sensory system
• Cycle time 100ms 50 - 200 ms
• Passes data to Image Store in unrecognized form
• Array of Pixels (or whatever it is) from eyes
• Sound Intensities from ears

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Sensory Store

• The input buffer of the senses
• Stores most recent input unrecognized
• Storage time and capacity varies by type
• Visual Nominal Range
• Capacity 17text letters 7 - 17 letters
• Decay Time 200ms 70 - 1000 ms
• Audio
• Capacity 5 text letters 4.4-6.6 letters
• Decay Time 1500 ms 900 - 3500 ms