Comp 15 - Usability and Human Factors

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Comp 15 - Usability and Human Factors

• Unit 3a - Cognition and Human Performance

This material was developed by Columbia
University, funded by the Department of Health
and Human Services, Office of the National
Coordinator for Health Information Technology
under Award Number 1U24OC000003.
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Overview

• Cognition and Human Computer Interaction in a
  cognitive engineering approach
• A model of human information processing including
  perception, attention, memory and cognition
• Mental models and interactive behavior
• Distributed cognition

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Cognition and Human Computer Interaction (HCI)
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HCI Cognitive Engineering Approach

• Principles, methods and tools to assess and guide
  design of computerized systems to support human
  performance
• Focus on attention, perception, memory,
  comprehension, problem solving, and decision
  making
• Analysis of cognitive tasks and processing
  constraints imposed by the human information
  processing system

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Cognitive Theory and HCI
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Driving with a Computer Keyboard

• Imagine trying to drive a car using a computer
  keyboard. The four arrow keys are used for
  steering, the space bar for braking and the
  return key for accelerating. To indicate left you
  need to press the F1 key and to indicate right,
  the F2 key. To sound your horn you need to press
  the F3 key. To switch the headlights on you need
  to use the F4 key and the F5 key for the
  windshield wipers. Now imagine as you were
  driving along a road a ball is suddenly kicked in
  front of you. What would you do? Bash the arrow
  keys and the space bar madly while pressing the
  F3 key?

Preece, J. Rogers, Y. Sharp, H. (2007)
Interaction Design Beyond Human-Computer
Interaction. 2nd Edition. New York, NY John
Wiley Sons. P. 92
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Human Information Processing
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A Model of Human Information Processing
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Perception
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Gestalt Organization Principles

• Perceptual organizing principle
• How we perceive structure in our environment
• Proximity
• Containment
• Similarity
• Closure
• Continuation
• Basic principles with clear implications for web
  design

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No Clear Grouping
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Proximity
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Containment
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Similarity
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Closure
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Anyones Guess
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Airport Status Example
Was the delay Boston or Westchester?

• Was the delay Boston or Westchester?

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Schedule 1
Newark
Philadelphia
On time
On time
JFK
Boston
On time
Delay
La Guardia
Westchester
On time
On time
Newberg
Long Island
On time
On time
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Simple Improvement 1
Newark
Philadelphia
On time
On time
JFK
Boston
On time
Delay
La Guardia
Westchester
On time
On time
Newberg
Long Island
On time
On time
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Simple Improvement 2
Newark - On Time
Philadelphia - On Time
JFK - On Time
Boston - Delay
La Guardia - On Time
Westchester - On Time
Newberg - On Time
Long Island - On Time
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Human Attention

• Selective Mechanism
• Resource needed for information processing
• Limited
• Sharable
• Flexible

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Selective Attention

• Ability to ignore extraneous information and
  focus on relevant inputs
• Performance typically declines as the number of
  sources of information increases
• Humans can only process information at a finite
  rate
• Information overload results in errors

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The Case of Bird Watching
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Computer Provider Order Entry Systems
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Representational Effect
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Digital vs. Analog
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Glucose and BP Representations
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Risk Representations (Ancker, 2007)