Chapter 7- User Centered

Design

By:Atul SabooHardik MishraMohit AlmalPankaj AgarwalSumeet Jalan

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.

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.

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.

Principles of Design for Understanding and Usability

• Provide a good Conceptual Model, the alternate actions and the result of the action

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

• Provide Feedback

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.

The Psychology of Everyday Actions

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.

The Psychology of Everyday Actions

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.

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.

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

Knowledge in the Head and In the World

Simplify the Structure of Task

• Task should be simple in structure• Minimize planning and problem solving• Use technological innovations

– The limitations of short-term memory (STM) are such that a person should not be required to remember more than about five unrelated items at one time

– The limitations of long-term memory (LTM) mean that information is better and more easily acquired if it makes sense, if it can be integrated into some conceptual framework.

Four major technological approaches can be followed to

Simplify

• Keep the task much the same, but provide mental aids- Everyday Notes

• Use technology to make visible what would otherwise be invisible thus improving feedback and the ability to keep control- Airplane

• Automate, but keep the task much the same- Digital Watches

• Change the nature of the task- Shoe Laces

Don’t take away control-Problems with over-automation

• Over reliance on automated equipment can eliminate a person's ability to function without it, a prescription for disaster

• A system may not always do things exactly the way we would like, but we are forced to accept what happens because it is too difficult (or impossible) to change the operation

 • The person becomes a servant of the system, no

longer able to control or influence what is happening.

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.

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,

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

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.

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

When all else fails, standardize

• If we examine the history of advances in all technological fields, we see that some improvements naturally come through technology, others come through standardization- Cars

• 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.

DeliberatelyMaking Things Difficult

• The rules of design are equally important to know here, however, for two reasons – Even deliberately difficult designs shouldn't

be entirely difficult.– Even if your job is to make something

difficult to do, you need to know how to go about doing it.

• EASY LOOKING IS NOT NECESSARILY EASY TO USE– Example: surfboard, ice skates, parallel

bars – Unnecessarily increasing or decreasing the

number of controls can detract from ease of use

The Advent of Technology

FROM QUILL AND INK

– Earlier times it was difficult and tedious to correct

– Well sorted thought process

– It embarked upon graceful rhetorical style

– Large section of text can be examined at a time

KEYBOARD AND MICROPHONE

– Corrections became simpler

– Rapid Speed– Less time involved in

planning– Language has become

colloquial and unstructured

– Working area is limited to the screen

To

HOME OF FUTURE: A PLACE OF COMFORT

OR A NEW SOURCE OF FRUSTRATION

• Smart House– Electric Appliances connected via “Information Bus”

(Lamps, Owens, Dishwashers etc).– A disk holding billion of information

• House of Knowledge– Libraries at fingertips– World information just a click away

A Look at what costs are attached to these

A NEW SOURCE OF FRUSTRATION

• Cost Attached– Costly with respect to the time and

effort by the author

– The difficulty of finding anything in such large data bases

What a Proper Design Can Do?

Errors are unavoidable but proper attention can lead to the following:

• Can help decrease the incidence and severity of errors by eliminating the causes

• Minimize the possibility of errors

• Make errors discoverable

Enjoy yourself and walk around the world examining the details

Thank You