[PPT] - Human-Computer Interaction 12. Design Principles (2) Last class PowerPoint Presentation

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Human-Computer Interaction

12. Design Principles (2)

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Last class

Psychological design principles

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Recap: Psychological principles

1. User sees what they expect to see. 2. Users have difficulty focusing on more than one activity at a time. 3. It is easier to perceive a structured layout. 4. It is easier to recognize something than to recall it.

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Recap: Gestalt theory

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User-centered design

User interface design knowledge

from users: need to know about the users and their tasks

Design iteratively!

Design principles

Theoretical: User interface design

knowledge from theory & experience

Experiential: Abstract, high-level

guides for design

Good Interaction Design

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Today

Norman’s design principles

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Norman’s Design Principles

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Usability

Usability is a measure of the effectiveness, efficiency and satisfaction with which specified users can achieve specified goals in a particular environment - ISO 9024

Usability is NOT identical to making things simple to use!!!

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Link: https://www.youtube.com/watch?v=yY96hTb8WgI

Norman’s Door

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Link: http://www.sunyoungkim.org/class/hci_sp18/pdf/The-Design-of-Everyday-Things- Revised-and-Expanded-Edition.pdf

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Norman’s 6 design principles

1. Visibility – can I see it? 2. Feedback – what is it doing now? 3. Mapping – where am I and where can I go? 4. Affordance – how do I use it? 5. Constraint – these are the things I can’t do 6. Consistency – I think I have seen this before

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1. Visibility

Just by looking, the user should know what to do :

State of the system
Possible actions

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1. Visibility

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1. Visibility
Sensor technology like auto faucets - not sure how to use - guess where to

put hands

Visible knobs, dials and buttons have been replaced by invisible and

ambiguous “active zone

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1. Visibility

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2. Feedback

“What is it doing now? what action has been performed? Sending back information immediately about what action has been done and what has been accomplished, allowing the person to continue with the activity : tactile, visual, verbal, audio, and combinations of these

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2. Feedback

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2. Feedback

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3. Mapping

Controls and displays should exploit natural mapping.

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3. Mapping

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3. Mapping

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3. Mapping

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3. Mapping

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4. Affordance

“Giving a clue to its operation”: An attribute of an object that allows people to know how to use it Examples :

Mouse button à push
Door handle à pull
Glass à see through

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4. Affordance

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4. Affordance

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4. Affordance confusion

Norman considers affordance to be a relationship between an object and a user, NOT property of an object

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5. Constraints

Relationship between actions and results in the world, between interface controls (their layout and movement) and their effect

Restricting the possible actions that can be performed
Helps prevent users from selecting incorrect options

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5. Constraints

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5. Constraints

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5. Constraints

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6. Consistency
Provide similar operations and similar elements to achieve similar task
System are usable and learnable when similar concepts are expressed in

similar ways: Eliminating confusing & reduce learning cost

Enabling people to quickly transfer prior knowledge to new contexts and

focus on relevant tasks -- easy to learn and remember!

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6. Consistency
Aesthetic
Style and appearance is repeated to enhance recognition, communicates

membership and sets emotional tone

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6. Consistency

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6. Consistency

http://www.hugeinc.com

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6. Consistency

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6. Consistency

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6. Consistency

Problems of Consistency:

Repetitive
Boredom
Monotony

à Inconsistency With a Purpose

Draw Attention
The Sake of Usability

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6. Consistency

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In this day and age, I feel like designers try to put a lot of different functions into just one control which can be very confusing or unhelpful if you do not know… As technology progresses and products seem to get smaller and smaller, it will be interesting to see how designers manage to fit more functions into less controls while still managing to make all these functions apparent to every user.”

Christine

“Norman claims that "the designer may be able to satisfy everyone" (28). One of the first things we learned was that attempting to please everyone will result in appealing to no one, so I would've liked Norman to go in to more detail about why he believed this. Personally, I believe that even with simple, everyday objects, someone somewhere will find a way to either break it or simply be unable to use

it. This does prove useful for design though, as it is a good reminder to take every

possible factor into account, no matter how small.” – Diego

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“I also like the mapping technique Norman mentioned. This is very similar to when we talked about Mental Models in class. Mapping is to design an object using a user's mental model. It can also apply to spatial mapping. Overall, this was a great read. It really exemplified the reason why designers should design for the

user. Additionally, it explains the importance of why we should simplify our
design. From this chapter, I learned that design is a balance of information. You

don't want to give the user too much or they will get overwhelmed. You don't want to give the user too little or they will have no clue what to do. Design is definitely more than just making things pretty. It's the psychology of how people interact with and understand objects.”

Anchalee

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