January 28, 1986
Chart given from Morton Thiokol to NASA
E. Tufte, pp. 46-47, Visual Explanations
Redrawn (Tufte)
Visual Perception
How many 3’s?
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The Eye’s Fovea
Gestalt Principles
• Grouping
– proximity, similarity, continuity
• Form perception
– closure, area, symmetry
Gestalt Principles
• Pop out
Gestalt Principles
• Motion, especially when coming into view
Gestalt Principles
• More difference gets recognized faster
• But simultaneous features can overload system
• Gestalt recognition proportional to resolution – i.e., works
better in the center (except for motion)
Remember:
• Periphery faster
• More light
sensitive
Color Orders (Edward Tufte)
Typography
The Competing Hypothesis: Familiarity
“Legibility, in practice, amounts simply to what one is
accustomed to” -- Eric Gill, 1931
=> No Robust Evidence for Serif Hypothesis
Implications for UI Design
• Need to think about human capabilities
• Need to design for tasks
Put it all together
http://nymag.com/nymetro/health/features/11700/index1.html
Memory
• Three “types”
– Short-term memory
– Intermediate
plans
– Long-term
ever happened to us
Conscious thought, calculations
Storing intermediate results, future
Permanent, remember everything
Memory: Sort Term
• Short Term (Working) Memory (WM)
– Gets basic recognition from Sensory Store
• “Stop sign” vs. “red octagon w/white marks”
– 7 +/- 2 “chunks”
• 4048946328 vs. 404-894-6328
– WM:
NominalRange
• Capacity:
7 chunks[5 - 9] chunks
• Decay Time: 7 seconds
[5 - 226] seconds
• Access Time: 70ms
[25 - 170] ms
Memory: Long Term
• Long Term Memory (LTM)
–
–
–
–
“Unlimited” size
Slower access time (100ms)
Little decay
Episodic & Semantic
• Why learn about memory?
– Know what’s behind many HCI techniques
– Predict what users will understand