2. ● Human Factors and Cognitive Ergonomics
● Brain Structure and Function
• Attention and consciousness
• Visual Perception
• Memory: Models and Processes
• Representation and Mental Models
• Decision Making and Reasoning
• Problem Solving and Creativity
● Instruments and Tools
● The Future ...
Agenda
4. Ergonomics (or human factors) is the scientific discipline concerned with the
understanding of interactions among humans and other elements of a system,
and the profession that applies theory, principles, data and methods to design
to optimize human well-being and overall system performance.
International Ergonomics Association
HFES (Human Factors and Ergonomics Society) has developed a technical
standard in conjunction with the American National Standards Institute:
ANSI/HFES 100-2007, Human Factors Engineering for Computer Workstations
In addition, two best-practices guides are available:
● HFES 200, Human Factors Engineering of Software User Interfaces
● HFES 300, Guidelines for Using Anthropometric Data in Product Design
Human Factors and Cognitive Ergonomics
1: Introduction
2: Accessibility
3: Interaction Techniques
4: Interactive Voice Response
5: Visual Presentation and Use of Color
6. The term ergonomics derived from the Greek ἔργον, meaning "work", and
νόμος, meaning "natural law".
Work + Natural Law = Ergonomics
Methods used to evaluate human factors and ergonomics:
• Surveys and questionnaires
• Systems analysis tool (SAT)
• Cognitive walkthrough (Usability Evaluation Method)
• Ethnographic analysis
• Iterative design:
1. Design the user interface
2. Test
3. Analyze results
4. Repeat
• Focus Groups
• Meta-analysis
• User analysis
• Task analysis
• etc.
Human Factors and Cognitive Ergonomics
Vitruvian Man, Leonardo da Vinci
7. Cognitive Ergonomics
Cognitive ergonomics studies cognition or mental processes, such as
• Attention
• Perception
• Memory
• Reasoning
• Prediction
• Learning
• Motor Response
• Mental Workload
• Decision-Making
• Problem Solving
• etc.
in order to optimize human well-being and system performance.
Human Factors and Cognitive Ergonomics
8. Human–Computer Interaction
Human–Computer Interaction (HCI) researches the design and
use of computer technology, focused on the interfaces
between people (users) and computers.
Wickens’s Principles for Display Design:
A ‘Display’ is a collection of artifacts or deliverables, that help
support perception. Displays help explain to humans via a
graphical form.
Wickens’s principles can be grouped under:
• Perceptual principles
• Mental Model principles
• Principles based on Attention
• Memory principles
Human Factors and Cognitive Ergonomics
9. Human Factors and Cognitive Ergonomics
Perceptual principles
1. Make displays legible (or audible)
2. Avoid absolute judgment limits
3. Top-down processing
4. Redundancy gain
5. Similarity causes confusion: Use distinguishable elements
Mental Model principles
1. Principle of pictorial realism
2. Principle of the moving part
Principles based on attention
1. Minimizing information access cost or interaction cost
2. Proximity compatibility principle
3. Principle of multiple resources
Memory principles
1. Replace memory with visual information
2. Principle of predictive aiding
3. Principle of consistency
11. BrainStructure and Function
• “If the brain was simple enough to be understood - we would be too
simple to understand it!”
—Marvin Minsky (Cognitive Scientist)
12. BrainStructure and Function
Question
How can we use research and knowledge about the brain, the
visual system, memory and Emotion to design more effective
products, services and systems?
13. BrainStructure
1. HindBrain (Reptilian):
Common to all animals
• Basic function (heart rate, breathing, body temperature)
2. MidBrain (Mammalian):
Limbic system
• Emotional functions (fear, happy, sad, …)
• Risk and reward
3. ForeBrain (Neocortex):
Higher cognitive function
• Problem solving
• Social cognition
• Language and abstract thought
BrainStructure and Function
20. BrainStructure and Function
[Attention] is the taking possession of the mind, in clear and vivid form, of one
out of what seem several simultaneously possible objects or trains of thoughts.
It implies withdrawal from some things in order to deal effectively with others.
—William James, Principles of Psychology
21. BrainStructure and Function
Functions of Conscious Attention
• Signal Detection
• Searching
• Selective Attention
• Divided Attention
Functions of Unconscious Attention
• Priming
• Top of the Tongue
• Blindsight
30. BrainStructure and Function
Visual Perception
Visual perception is the end product of vision” It can
be described as the way the brain interprets what
the eyes see.
Perceptual Processing Categories:
• Visual Discrimination: ability to be aware of the
distinctive features of forms including shape,
orientation, size, and color.
• Visual Figure Ground: ability to distinguish an
object from irrelevant background information.
• Visual Closure: ability to recognize a complete
feature from fragmented information.
32. BrainStructure and Function
Visual perceptionProcess
• Bottom-up:
• Low level features
• Patterns
• Objects
• Top-down:
• Task or goal Oriented
• Holistic
33. BrainStructure and Function
Gestalt laws
• Law of Proximity
• Law of Similarity
• Law of Figure and Ground
• Law of Continuity
• Law of Closure
• Law of Simplicity
37. BrainStructure and Function
It seems that the human mind has first to construct forms independently before
we can find them in things … Knowledge cannot spring from experience alone,
but only from a comparison of the inventions of the intellect with observed fact.
—Albert Einstein
47. BrainStructure and Function
Mental Models
Mental models are knowledge structures that individuals
construct to understand and explain their experiences. The
models are constrained by the individuals’ implicit theories
about these experiences, which can be more or less
accurate. (Johnson-Laird, 2001)
A mental model is what the user believes about the system
• A mental model is based on belief, not facts.
• Individual users each have their own mental model.
48. BrainStructure and Function
How People FormMental Models
• Observation
• immersive experience Emotion
• Culture
User-Centered Design Approaches
• User Personas
• Empathic Design (The ability to understand and identify with another
person’s context, emotions, goals, and motivations.)
• Contextual Inquiry (study users in their own natural environment)
Counterfactual Thinking
55. BrainStructure and Function
Creative Works
• Replication
• Redefinition
• Forward Movement
• Advance Forward Movement
• Redirection
• Redirection from a point in the Past
• Starting Over
• Integration
57. BrainStructure and Function
The Wisconsin Card Sorting Task. The WCST
encourages subjects to adopt a certain rule like ‘
the yellow color predicts correct cards ’ . At some
point a different rule comes into play, such as
number or shape of items. This is a challenge to
our ability to think of alternatives to the first rule.
60. Instruments and Tools
Eye Tracking
Eye tracking is the process of measuring either the point of gaze (where
one is looking) or the motion of an eye relative to the head.
The most commonly visualizations methods are:
• Animated representations of a point on the interface
• Static representations of the saccade path
• Heat maps
• Blind zones maps, or focus maps
63. Instruments and Tools
Eye Tracking Metrics
Engagement
• Number of Fixation
• Total dwell time
• Percentage of time on an area
Processing
• Fixation
• Duration
Findability
• Time to first fixation
• Number of fixations
• Prior to first fixation
Processing Order
• Gaze path
Comprehension
• Repeat fixations
Workload/Excitement
• Pupil dilation
