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UGS 302
Usability and UserCentered Design
Day 3
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Objectives
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After this class you will be able to (it is my
hope!):
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Describe some eye physiology
Explain how the visual system works (somewhat)
Identify visual cues to depth
Be able to describe what it means to say “perception is
not the simple sum of sensations.”
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Whole point . . .
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• Let’s design systems to fit people
instead of the other way around.
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Human Information Processing
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• How do human beings take in and process
information?
– Sensory psychology – how humans transform physical
energy (e.g., light and sound waves) into sensory signals to
and in the brain.
– Perceptual psychology – how humans interpret these
sensory signals as perceptions.
– Cognitive psychology – how humans think about these
perceptions, and previous experiences, and their own mental
creations, and . . .
– Psycholinguistics – The psychology of language -- what
goes on between the time I have a thought and you have the
same (or similar!) thought, whether I say it or write it.
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Ear Physiology
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Basilar membrane
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Eye Physiology
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Eye Muscles
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Visual Field
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Retinal Physiology
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Distribution of Rods and Cones
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Visible Spectrum
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Visual Sensitivity
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Neural Pathways
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Aftereffect
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Ambiguous Figure
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Sensation/Perception
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• POINT: Perceptions are made up of more
than just a collection of sensations!
• OTHER things influence our perceptions, e.g.,
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Our experiences
Our biases
The context
Our current emotional state
Etc.
• So, what does that have to say about
designing human-computer interfaces???
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Perceptual Psy – Color Vision
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• Color perception – 3 types of cones (RGB)
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Perceptual Psy -- Depth
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• Different visual cues to depth
– Oculomotor vs. Visual
• Oculomotor – Lens accommodation and
extraocular muscle convergence are “read” by
the brain
• Visual: Binocular vs. Monocular
– Binocular – Stereopsis (retinal disparity)
– Monocular (next screen)
» Static
» Motion parallax
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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More Depth Cues
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• Monocular
– Static
• Interposition
• Size
• Perspective
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Linear perspective
Texture gradient
Aerial perspective
Shading
– Motion parallax
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Monocular Cues -- Interposition
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Monocular Cues -- Size
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Monocular Cues – Linear
Perspective
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Monocular Cues – Texture
Gradient
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Sooooo . . .
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The grass really
IS
greener on the other side of the fence!!!
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Monocular Cues – Aerial
Perspective
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Monocular Cues -- Shading
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Monocular Cues – Motion
Parallax
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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More visual perception
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• Illusions – and what they tell us about
vision
• Ponzo illusion
• Muller-Lyer illusion
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Ponzo Illusion
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Muller-Lyer Illusion
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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Homework
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• Finish reading The Invisible Gorilla.
• Start reading The Design of Everyday Things
• For Thursday -- Bring to class picture or verbal
description of good and poor designs. NOT
web sites. Physical objects.
R. G. Bias | School of Information | UTA 5.424 | Phone: 512 471 7046 | rbias@ischool.utexas.edu
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