CMP2019M Human-Computer Interaction
Week 3 – Core Concepts: Usability and Design Heuristics
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– Perception
Last week
Understanding Human Cognition
– Memory – Learning
This week
A brief look through some core concepts in HCI:
•Part I: Understanding Human Cognition (Psych 101) – Perception,
– Memory – Learning
•Part II: Designing for Human Cognition – Usability
– Design Heuristics
• Sheiderman & Nielsen
Part II: Designing to Accommodate Human Cognition
Defining Usability
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?
What is Usability?
What is Usability?
“The effectiveness, efficiency and satisfaction with which specified users achieve specified goals in particular environments.” ISO 9241
• • •
What is Usability?
Lots of different ways of considering / measuring this
It depends on what the software is supposed to do
Efficiency
– Time taken to do task – Errors
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– Number of tasks completed in a given time
Effectiveness
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– Questionnaires
Satisfaction
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Engineering
Nielsen (1993): Usability
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usability research – progress
There are vast amounts of
in instruments, procedures, specialised for different user groups / devices
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most software / devices
It is inherent in the design of
Usability
Why Care about Usability?
“Sidetalking”
Designing Usable Systems
What are Usability Heuristics?
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to ensure that their software follows established usability principles
Essentially rules-of-thumb that “experts” use
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been found useful.
They are used primarily because they have
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people.
Applied before software is exposed to real
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– Nielsens (1993) 10 usability heuristics – Schneidermans (1998) 8 golden rules
There are a few different versions
Nielsen & Shneiderman
@benbendc
What are Usability Heuristics?
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understanding of perception, memory & learning (cognitive psychology)
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A lot of these concepts are based on our
The rest of this lecture will look (very) briefly at these
Nielsen’s 10 Usability Heuristics
http://www.useit.com/papers/heuristic/heuristic_list .html
1.Visibility of system status
2.Match between system and the real world
3.User control and freedom
4.Consistency and standards
5.Error prevention
6.Recognition rather than recall
7.Flexibility and efficiency of use
8.Aesthetic and minimalist design
9.Help recognize, diagnose, and recover from errors 10.Help and documentation
1. Visibility of System Status
2. Match between System/World
3. User Control & Freedom
4. Consistency & Standards
4. Consistency & Standards
5. Error Prevention
6. Recognition over Recall
Flexlibility Efficiensy
7. Flexibility & Efficiency
8. Aesthetic & Minimalist Design
9. Recognise, Diagnose, Recover
10. Help & Documentation
Shneiderman’s 8 Golden Rules
• • • • • • • • •
http://lncn.eu/dtu
Strive for consistency.
Enable frequent users to use shortcuts. Offer informative feedback.
Design dialog to yield closure.
Offer simple error handling.
Permit easy reversal of actions. Support internal locus of control. Reduce short-term memory load.
Do these heuristics make sense? Why (not)?
What about…
GAMES EXAMPLE
• In some cases, complexity is “good” because it simulates the real world
• Can’talwayssimplify– but doesn’t mean you shouldn’t try your best as a designer if you have the freedom to do so!
• Findsuitablesolutions
• Becauseinsomecases, complexity is a horrible idea – not just annoying, but putting lives at risk
• Particularlyimportantas technology makes its way into our daily lives!
• Be mindful – if you’re the designer, you carry responsibility!
Next week: Beyond Usability –
Accessible Design
Remember:
We should care about cognition etc. because our body is our interface to communicate with technology.
(Most things these days are designed for the average white male, and while that’s good news for a lot of people in this room, it doesn’t quite work for everybody.)
Do you have any questions?