January 28, 1986. Chart given from Morton Thiokol to NASA E. Tufte, pp. 46-47, Visual Explanations.

January 28, 1986

Chart given from Morton Thiokol to NASA

E. Tufte, pp. 46-47, Visual Explanations

Redrawn (Tufte)

Visual Perception

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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

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Memory

• Three “types”– Short-term memory Conscious thought, calculations– Intermediate Storing intermediate results, future

plans– Long-term Permanent, remember everything

ever happened to us

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