The document discusses human factors and ergonomics, which aims to optimize human well-being and system performance by understanding the interaction between humans and elements of a system. It covers cognitive ergonomics and how people process information. It also discusses human-centered design and how to design interactive systems based on user needs through methods like contextual design. Finally, it discusses cognitive biases, mental models, memory, perception and various laws and principles of human factors like Fitts' law.

1. Hamed Abdi - June 2018
Human Factors
Every User has a Mind!

2. “
“People ignore design that ignores people.”
• Frank Chimero (Design Director)

3. What is Human Factors?
or
What is Ergonomics?
Vitruvian Man, Leonardo da Vinci
Question

4. Human Factors or Ergonomics is the scientific discipline
concerned with the understanding of interactions among
humans and other elements of a system [humans, services,
processes, things], and the profession that applies theory,
principles, data and methods to design to optimize human
well-being and overall system performance.
International Ergonomics Association

5. 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
• HFES 200, Human Factors Engineering of Software User Interfaces
• HFES 200.1: Introduction
• HFES 200.2: Accessibility
• HFES 200.3: Interaction Techniques
• HFES 200.4: Interactive Voice Response
• HFES 200.5: Visual Presentation and Use of Color
• HFES 300, Guidelines for Using Anthropometric Data in Product Design

6. Cognitive Ergonomics
Cognitive ergonomics (Cognetics) studies cognition
or mental processes, such as:
• Attention
• Perception
• Memory
• Reasoning
• Prediction
• Learning
• Motor Response
• Decision Making
• Problem Solving
• etc.

7. Changing the World with
Human-Centered Design
or
User-Centered Design

8. Human[User]-centered design is an approach to interactive
systems development that aims to make systems usable and
useful by focusing on the users, their needs and
requirements, and by applying human factors/ergonomics,
usability knowledge, and techniques.
ISO 9241-210:2010

9. H/UCD Approaches
• Cooperative Design
• Participatory Design
• Contextual Design (Customer-Centered Design)
H/UCD Methods (TP)
• IDEO
• Stanford DSchool
• Double Diamond

11. “
“What people say, what people do, and what they
say they do are entirely different things.”
• Margaret Mead (Anthropologist)

12. Behavioral Sciences
or
Cognitive Sciences?
Question

13. ???
Cognition
Behavior

14. Information Processing System

15. Biases &
Errors

17. Common Cognitive Biases
UX Designer
ConfirmationBias
Observer-Expectancy
Effect
Participants
SocialDesirability
Bias
HawthorneEffect
Research Design
WordingBias
SamplingBias

18. “
“To break a mental model is harder than splitting the
atom.”
• Albert Einstein (Scientist & Theoretical Physicist)

21. 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 based on belief, not facts.
• Individual users each have their own mental model.
How People Form Mental Models
• Observation
• Immersive Experience Emotion
• Culture

22. Mental
Models
Cognition
Behavior

23. “
“What if nothing exists and we're all in somebody's
dream?”
• Woody Allen (American Director)

24. What if…
Counterfactual
Thinking
The Man in the High Castle

25. Counterfactual Thinking
Counterfactual thoughts are mental representations of
alternatives to past events, actions, or states.
Why do we have counterfactual thoughts?
• Risk Aversion
• Behavior Intention
• Goal-Directed Activity
• Collective Action
• Benefits and Consequences
Platonia (Multiverse Theory)

26. Overload
Cognitive Load

27. Human Memory
Sensory Memory
(<1 Sec)
Short-term
(Working) Memory
(<1 min)
Long-term
Memory
(Life Time)
Explicit Memory
(Conscious)
Declarative
Memory
(Facts, Events)
Episodic Memory
(Events,
Experiences)
Semantic Memory
(Facts, Concepts)
Implicit Memory
(Unconscious)
Procedural
Memory
(Skills, Tasks)

30. Why cognitive load matters in web design?
• Raise of bounce rate
• Shallow depth of user visits
• Raise of time per visit without raise of conversion
• Decrease of conversion
• Decrease of the number of returning users
How to reduce cognitive load?
• Be Predictable
• Use schemes that already exist and users know them
• Make instructions simple (Content Strategy)
• Design mindful of how users read online
• Reduce visual clutter
• Reduce number of tasks user has to perform
• Reduce amount of information user has to keep in mind
• etc.

33. “
“I hear and I forget. I see and I remember. I do and I
understand.”
• Confucius (Philosopher)

34. Visual Perception

36. Two visual systems

37. Visual perception Process
• Bottom-up:
• Low level features
• Patterns
• Objects
• Top-down:
• Task or goal Oriented
• Holistic

39. Gestalt laws
• Law of Proximity
• Law of Similarity
• Law of Figure and Ground
• Law of Continuity
• Law of Closure
• Law of Simplicity

40. Gestalt
Law of Proximity
Elements that are placed close to each other will often be perceived as one group.

41. Gestalt
41
Law of Similarity
Objects that look alike, with similar components or attributes, are more likely to be organized together.

42. Gestalt
Law of Figure and Ground
Viewers will perceive an object (figure) and a surface (ground) even in shapes are grouped together.

43. Gestalt
Law of Continuity
Objects will be grouped as a whole if they are co-linear, or follow a direction

44. Gestalt
Law of Closure
In perception there is the tendency to complete unfinished objects. We tend to ignore gaps and complete
contour lines.

45. Gestalt
45
Law of Simplicity
Figures are seen as their simple elements instead of complicated shapes.

48. “
“Where there is no law, there is no freedom.”
• John Locke (Philosopher)

49. 01. Doherty Threshold
Productivity soars when a computer and its users
interact at a pace (<400ms) that ensures that neither
has to wait on the other.
• Provide system feedback within 400ms in order to keep users’
attention and increase productivity.

50. 02. Fitts’s Law
The time to acquire a target is a function of the
distance to and size of the target.
• Make elements you wish to be easily selectable large and
position them close to users.
• This law especially applies to buttons, which the purpose of
these elements is to be easy to find and select.

51. 03. Hick’s Law
The time it takes to make a decision increases with the
number and complexity of choices.
• More choices results in longer to think about these choices
and make a decision.
• Simplify choices for the user to ensure by breaking complex
tasks into smaller steps.
• Avoid overwhelming users by highlighting recommended
options.

52. 04. Jakob’s Law
Users spend most of their time on other sites. This
means that users prefer your site to work the same
way as all the other sites they already know.
• You can simplify the learning process for users by providing
familiar design patterns.

53. 05. Law of Common Region
Elements tend to be perceived into groups if they are
sharing an area with a clearly defined boundary.
• Adding borders (creating common regions) around an
element or group of elements is an easy way to create
separation from surrounding elements.

54. 06. Law of Pragnanz
People will perceive and interpret ambiguous or
complex images as the simplest form possible,
because it is the interpretation that requires the least
cognitive effort of us.
• The human eye likes to find simplicity and order in complex
shapes because it prevents us from becoming overwhelmed
with information.

55. 07. Law of Proximity
Objects that are near, or proximate to each other, tend
to be grouped together.
• The law of proximity is useful by allowing users to group
different clusters of content at a glance.

56. 08. Law of Similarity
The human eye tends to perceive similar elements in a
design as a complete picture, shape, or group, even if
those elements are separated.
• Ensure that links and navigation systems are visually
differentiated from normal text elements, and are
consistently styled.

57. 09. Law of Uniform Connectedness
Elements that are visually connected are perceived as
more related than elements with no connection.
• Group functions of a similar nature so they are visually
connected via colors, lines, frames, or other shapes.

58. 10. Miller’s Law
The average person can only keep 7 (plus or minus 2)
items in their working memory.
• Chunking is an effective method of presenting groups of
content in a manageable way. Organize content in groups of
5-9 items at a time.

59. 11. Occam’s Razor
Among competing hypotheses that predict equally
well, the one with the fewest assumptions should be
selected.
• Analyze each element and remove as many as possible,
without compromising the overall function.

60. 12. Pareto Principle
The Pareto principle states that, for many events,
roughly 80% of the effects come from 20% of the
causes.
• Focus the majority of effort on the areas that will bring the
largest benefits to the most users.

61. 13. Parkinson’s Law
Any task will inflate until all of the available time is
spent.
• Focus the majority of effort on the areas that will bring the
largest benefits to the most users.

62. 14. Serial Position Effect
Users have a propensity to best remember the first
and last items in a series.
• Placing the least important items in the middle of lists can be
helpful because these items tend to be stored less frequently
in long-term and working memory.
• Positioning key actions on the far left and right within
elements such as navigation can increase memoriziation.

63. 15. Tesler’s Law
Tesler's Law, also known as The Law of Conservation of
Complexity, states that for any system there is a
certain amount of complexity which cannot be
reduced.

64. 16. Von Restorff Effect
The Von Restorff effect, also known as The Isolation
Effect, predicts that when multiple similar objects are
present, the one that differs from the rest is most
likely to be remembered.
• Make important information or key actions visually
distinctive.

65. 17. Zeigarnik Effect
People remember uncompleted or interrupted tasks
better than completed tasks.
• Use progress bars for complex tasks to visually indicate when
a task is incomplete, and thus increase the likelyhood it will
be completed.

66. “
“We become what we behold. We shape our tools
and then our tools shape us.”
• Marshall McLuhan (Philosopher)

68. 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

71. 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

72. Electroencephalography (EEG)

74. Magnetoencephalography (MEG)

75. Functional Magnetic Resonance Imaging (fMRI)

76. “
“The best way to predict your future is to create it.”
• Abraham Lincoln

77. ThankyouforyourAttention