April 19, 2004“Design of User-Friendly Systems” DLC, 2004 1 Design of User Friendly Systems Joel...

April 19, 2004 “Design of User-Friendly Systems”DLC, 2004

1

Design of User Friendly Systems

Joel ClawsonGenevieve HudakBrock LaMeres

Kitty Turner


2

Introduction

• Topic: – Design

• Objective:– To understand good and bad design practices as

pertained to the psychology of users


3

Agenda

• The dysfunction of everyday things

• The psychology of everyday actions

• Knowledge in the head and in the world

• Knowing what to do

• To err is human

• User-centered design

• Overview of Things That Make Us Smart


4

Characteristics of Objects

• Easy to understand• Easy to interpret• Contain visible clues

to operation

• Difficult to Use• Frustrating• No clues/False clues• Get in the way of

normal thought processes on operation

Well Designed Poorly Designed


5

Frustrations of Everyday Life

• Poor Visibility

• Lack of Natural Signals

• Poor Mappings

• Poor Instructions

• Poor Relations between old, known functions and similarly named new ones


6

Psychology of Everyday Things

• Affordances– Plates → Pushing– Knobs → Turning– Slots → Inserting

• False Causality

• Conceptual Models


7

Principles of Design for Understanding and Usability

• Provide a good Conceptual Model

• Make things Visible– Provide good mappings– Provide natural relationships– Don’t overload a control

• Provide Feedback


8

The Psychology of Everyday Actions

“Humans will try to figure it out”

A user sits down at an interface with a goal. The user…

1) Observes what functionality is available.2) Forms a conceptual model of how the system works.3) Takes an action to achieve the goal.4) Observes the outcome of the action, was it right or wrong?

5) Either Reinforces or Discredits his conceptual model.6) Continues until the goal is accomplished.


9


This is good if ???

- The interface understands how the user approaches the system.- Allows the user to explore the system risk free.- Provides only necessary functionality at the top level.- Handles Errors.

This is bad if ???

- Inappropriate actions result in no or incorrect feedback.- There is no forgiveness for mistakes.- The model of the system varies from the conceptual model of the user.


10


A good system understands how users get lost….

- Can the user build a conceptual model of the system from the interface? (false models, misconceptions)

- Does the feedback of actions discredit the model? (Falsely Blaming yourself, Blaming the wrong cause)

- Does the system reinforce misconceptions? (Learned Helplessness, Taught Helplessness)


11


A good example:

Delete Confirmation - Confirmation that an action was taken. - A correlation of the action and observation. - A way out of a dangerous situation.

A bad example:

MS Word Auto Format - no relationship between action and outcome. - no consistency between the outcomes. - not always possible to reverse action and get back to where we started.


12

The Psychology of Everyday Actions-Design Aids to Compliment the User’s Thought Process…

1) Visibility

The user will see what is available and act accordingly.

2) A Good Conceptual Model

The user will form a simple model, does the system allow models to be formed?

3) Good Mapping

Is there a correlation between the action and the outcome?

4) Feedback

Users reinforce/discredit their model according to the reaction they get from an

action. If there is no action, the user is lost.


13

Knowledge in the Head and In the World

“Digital Media Offers Overwhelming Information”

1) There is too much information for the user to remember.

2) Designers must Decide which information will be memorized and which will be stored in the system.


14


What are the Tradeoff ???

Knowledge in the World Knowledge in the Head

Retrievability: Available when visible/audible Requires Memory Search

Learning: Not Required Required

Efficiency: Slow Fast once Retrieved

First Encounter: Easy Difficult


15


What do we do ???

- Exploit the Nature of Human Thought

- Humans want to form a “conceptual model” of all things.

- Information without a model is difficult to remember.

- Try to communicate Concepts instead of Raw Information

Ex) 1) Where do you find the information vs. What is the information?

2) How Features Alter the System vs. What Specifically do the features do?


16


Mappings Can Help “Knowledge in the World”

“Stove Control Example”No Mapping Natural Mapping

This exploits the human need for a conceptual model through “mappings”


17


Understanding Memory Can Help “Knowledge in the Head”

1) Memory for Arbitrary Things(difficult, standardization helps)

2) Memory for Meaningful Relationships(efficient)

3) Memory through Explanation

(conceptual models)


18

Physical and Logical constraints

Physically constrain possible operations• Rely upon properties of the physical world• Examples:

– Large peg cannot fit into small hole– Keys can have only one of two orientations when inserted into a

vertical slot

Logical constraints take advantage of natural mappings and relationships

• Location and operation should follow these natural mappings:– Two switches to controls two lights: left switch should control left

light and right switch should control right light– Last piece of a jigsaw puzzle, naturally constrained to go in the

empty hole


19

Cultural and Semantic constraints

Cultural constraints: Knowing how to act in cultural situations such as at a restaurant

• Culturally acceptable behavior frames– Notice these when they are violated, such as standing in

an elevator facing the rear– Differ from culture to culture

Semantic constraints rely on– the meaning of the situation– the user’s knowledge of the situation and the world

• Example:– How to sit in a chair with arms, sit with legs over open

edge


20

Visibility and FeedbackVisibility: “Making relevant parts [or the correct action] visible”– easier

said than done• Doors

– Unclear design of many doors as to which side of the door opens• Switches

– Many switches controlling different things– Natural mapping of switches often not exploited; which direction of the

switch is on/off

Feedback: “Give each action an immediate and obvious effect.”• Use sound to make things visible

– Whistle of tea kettle when water boils– Click when toast pops up– Change in pitch when vacuum is clogged

• Having a good display – visual feedback– Lets the user know what effect their actions have


21

Capture and Data-Driven Errors

Capture error: When “a frequently done activity suddenly takes charge instead of (captures) the one intended.”

• Occurs when two different action sequences have initial stages in common, where one is well practiced and the other unfamiliar

Examples:• Going to change your clothes for dinner and finding

yourself in bed• Get in your car on Sunday to go to the store and end up

going to work instead

Data-driven error: Occurs when sensory data interferes with the current action sequence.

• Automatic actions are data-driven.


22

Description and Mode Errors

Description error: When the intended action has a lot in common with other actions that are possible.

• Comes from imprecise internal descriptions.• Occurs when the wrong and right objects are physically near

each other.Example:• Flipping the wrong switch in a long row of switches

Mode error: When controls must perform more than one action, depending on the mode

• Errors occur when the mode is not made visible• Especially prevalent on computer systems and digital

watches


23

Associative activation and Loss-of-activation Errors

Associative activation error: When internal thoughts and associations trigger actions.

Examples:• Thinking something you shouldn’t say and then

saying it.• Answering your telephone ‘come in’

Loss-of-activation error: Plainly, forgetting.• Can happen in the middle of doing something,

such as walking into a room and forgetting why you went there.


24

To Err is Human

Types of errors

Visibility of Errors

Conceptual models that lead to error

Structure of tasks:•Wide and deep

•Shallow •Narrow

Explaining away errors

Social Pressures

Forcing Functions


25

More Info

Flanders, Vincent. “Web Pages that Suck”. http://www.webpagesthatsuck.com/dailysucker/


26

User-Centered Design

• Good design

• The user says “Yes, I see” or “Of course”. A simple explanation is sufficient.

• Bad design

• The user says “How am I going to remember that?” after the explanation.


27

7 principles of good designOR

7 principles for transforming difficult tasks into simple ones

1. Use both knowledge in the world and knowledge in the head.

2. Simplify the structure of the tasks.3. Make things visible: bridge the gulfs of Execution and

Evaluation.4. Get the mappings right.5. Exploit the power of constraints, both natural and

artificial.6. Design for error.7. When all else fails, standardize.


28

Use knowledge in the world and knowledge in the head

• Users are more comfortable and learn better when the knowledge they need to perform a task is readily available in the world or through constraints.

• Users perform faster and more efficiently when they can synthesize the knowledge needed for their task.

• So it should be easy to go back and forth – to combine knowledge in the head with knowledge in the world.

• The designer must develop a conceptual model for the user that captures the important parts of the device and that is understandable by the user.


29

Simplify the structures of tasks

• The amount of planning and problem solving for a task should be minimized.


30

Make things visible

• On the execution side of an action:

• So that users know what actions are possible and how the actions can be done.

• On the evaluation side of an action:

• So that users know what the results of the actions are and the current state of the system.


31

Get the mappings right

• Make sure the user can understand the relationship between intentions and possible actions,

• actions and their effects on the system,

• the actual system state and what is reflected in the interface,

• and the perceived system state and the needs, intentions and expectations of the users.


32

Exploit the power of constraints, both natural and artificial

• Use natural and artificial constraints to make users feel that there is only one possible action.


33

Design for error

• Assume that any error is possible and plan for it.

• Allow users to recognize errors and recover from them.

• Make it easy to reverse operations and hard to do

irreversible actions.


34

When all else fails, standardize

• When the above principles cannot be put into place, standardize the actions, layout, display, and results.

• With standardization, users only have to learn it once but they must be trained to the new standard.


35

Knowing what to do

ConstraintsPhysical and Logical:

Good:http://enhancer.colorado.edu:6400/~hudakg/potentialBS.html

Cultural and Semantic: Good:http://www.denver.org/index.asp

Bad: http://www.aiwa.com/flash.html

Visibility and FeedbackVisibility:

Good:http://enhancer.colorado.edu:6400/~hudakg/potentialBS.html

Bad: http://www.chapcap.com/main.htm

Feedback:Good: http://www.newgrounds.com/

Bad: http://www.critterschoice.com/

http://enhancer.colorado.edu:6400/~hudakg/potentialBS.html

http://enhancer.colorado.edu:6400/~hudakg/potentialBS.html

http://www.critterschoice.com/


36

Human Centered Technology

• Aimed at aiding cognition– Often interferes and confuses– Should be aimed at the needs of people

• Two Kinds of Cognition– Experiential– Reflective


37

Kinds of Learning

• Accretion– Accumulation of Facts

• Tuning– Practice to make reflective tasks become

experiential

• Restructuring– Acquiring new concepts


38

Representation

• Cognitive Artifacts– What make us smart– Provide abstract representations– Represent the important ideas

• Match the Artifact to the Task

• Naturalness Principle:– Experiential cognition is aided when the

properties of the representation match the properties of the object/idea being represented


39

Fitting the Artifact to the Person

• People are better at Perception than Abstraction and Symbolism

• Appropriateness Principle:– The representation used by the artifact should

provide exactly the information acceptable to the task: neither more nor less.

• People seek understandings, causes, purpose


40

The Human Mind

• Machines use different principles than people– They complement each other– Details vs. Representation


41

Distributed Cognition

• Distributed Intelligence– Knowledge is in the world

• Impossible means Impossible– Properties of the world

• Accuracy is not always important


42

Organizing Knowledge

• Hierarchical

• Spatial

• Temporal


43

Conclusion

• User-centered design– About the USER– Thinking– Interaction with world


44

Questions ?

April 19, 2004“Design of User-Friendly Systems” DLC, 2004 1 Design of User Friendly Systems Joel...

Documents

Transcript of April 19, 2004“Design of User-Friendly Systems” DLC, 2004 1 Design of User Friendly Systems Joel...