HCI Unit 3.pptx

Human Computer Interaction
UNIT - 3
Guidelines in HCI

CONTENTS
1. Shneiderman’s Eight Golden Rules.
2. Norman’s Seven Principles.
3. Norman’s model of Interactions.
4. Nielsen’s ten heuristics with example of its use heuristic evaluation.
5. Contextual inquiry.
6. Cognitive Walkthrough.

Shneiderman’s Eight Golden Rules.
• Strive for consistency
• Enable frequent users to use shortcuts.
• Offer informative feedback.
• Design dialogue to yield closure.
• Offer simple error handling.
• Permit easy reversal of actions.
• Support internal locus of control.
• Reduce short-term memory load.

Strive for consistency
Strive for consistency by utilizing familiar icons, colors, menu
hierarchy, call-to-actions, and user flow when designing similar
situations and sequence of actions. Standardizing the way information is
conveyed ensures users are able to apply knowledge from one click to
another; without the need to learn new representations for the same
actions. Consistency plays an important role by helping users become
familiar with the digital landscape of your product so they can achieve
their goals more easily.

Enable frequent users to use shortcuts.
With increased use comes the demand for quicker methods of
completing tasks. For example, both Windows and Mac provide users
with keyboard shortcuts for copying and pasting, so as the user becomes
more experienced, they can navigate and operate the user interface more
quickly and effortlessly.

Offer informative feedback.
The user should know where they are at and what is going on at all times.
For every action there should be appropriate, human-readable feedback
within a reasonable amount of time. A bad example we often see is when
an error message shows an error-code instead of a human-readable and
meaningful message.

Design dialogue to yield closure.
Don’t keep your users guessing. Tell them what their action has led them
to. For example, users would appreciate a “Thank You” message and a
proof of purchase receipt when they’ve completed an online purchase.

Offer simple error handling.
No one likes to be told they’re wrong, especially your users. Systems
should be designed to be as fool-proof as possible, but when unavoidable
errors occur, ensure users are provided with simple, intuitive step-by-step
instructions to solve the problem as quickly and painlessly as possible.
For example, flag the text fields where the users forgot to provide input in
an online form.

Permit easy reversal of actions.
Designers should aim to offer users obvious ways to reverse their
actions. These reversals should be permitted at various points whether it
occurs after a single action, a data entry or a whole sequence of actions

Support internal locus of control.
Allow your users to be the initiators of actions. Give users the sense that
they are in full control of events occurring in the digital space. Earn their
trust as you design the system to behave as they expect.

Human attention is limited and we are only capable of maintaining
around five items in our short-term memory at one time. Therefore,
interfaces should be as simple as possible with proper information
hierarchy, and choosing recognition over recall.
Reduce short-term memory load

2. Norman seven principle
To assess the interaction between human and computers, Donald Norman in 1988
proposed seven principles. He proposed the seven stages that can be used to transform
difficult tasks. Following are the seven principles of Norman −
i. Use both knowledge in world & knowledge in the head.
ii. Simplify task structures.
iii. Make things visible.
iv. Get the mapping right (User mental model = Conceptual model = Designed
model).
v. Convert constrains into advantages (Physical constraints, Cultural constraints,
Technological constraints).
vi. Design for Error.
vii. When all else fails − Standardize.

Norman 7 principles
Use both knowledge in world & knowledge in the head.
People work better when the knowledge they need to do particular task
available externally, make a product to increase there efficiency of system
as per user knowledge.
Simplify task structures
Task need to be simple in order to avoid complex problem solving and
excessive memory load. Example : Breakdown into simple structure.

Continue
Make things visible
The interface should make clear what the system can do and how this is
achieved. User should enable to see clear effects of their action on the system.
Get the mapping right
User intention should map clearly onto system control and system events.
Control, sliders and dials should reflect the task, so a small movement have a
small effect and large movement a large effect.
Convert constrains into advantages
Constraints are things in the world that make it impossible to do anything but
the correct action in the correct way.
Physical constraints of the designed guide will be provided to the users to
complete the task.

Continue
Design for Error
To err is human, so anticipate the errors the user could make and designed
recovery into the system.
When all else fails − Standardize
If there is no natural mapping s then arbitrary mapping should be standardized
so that users only have to learn them once.
It is standardization principles that enables drivers to get into a new car and
drive it very little difficulty – Key control and standardized.

Donald Norman Model of Interaction
1. In order to make good decisions, it is important to know how human beings
are making decisions when the pursue an objective.
2. Usually, when somebody is planning to interact with the object does several
steps.
3. This steps could be divided into two categories called Gulfs.
• Gulf of Execution where we tends to discover the object properties.
• Gulf of Evaluation where we get feedback related to our interaction.
Norman model of interaction (1988) – most influential in HCI.

Seven stage of Donald Norman Model
 Established the goal.
 Forming the Intention.
 Specifying action sequence.
 Execution the action.
 Perceiving the system state.
 Interpreting the system state.
 Evaluating the system state with respect to goals and intentions.

Execution and Evaluation Loops

Continue
Goal
1. User establishes the goal.
Execution
1. Formulates intentions.
2. Specifies action at interface
3. Executes actions
Evaluations
1. Perceives system state.
2. Interprets system state.
3. Evaluates system state with respect to goal.

Nielsen’s ten heuristics
 Visibility of system status.
 Match between system and real world.
 User control and freedom.
 Consistency and standards.
 Error prevention.
 Recognition rather than Recall.
 Flexibility and efficiency of use.
 Aesthetic and minimalist design.
 Help, diagnosis and recovery from errors.
 Documentation and Help.

Visibility of system status
 The design should always keep users informed about what is going on,
through appropriate feedback within a reasonable amount of time.
 When users know the current system status, they learn the outcome of
their prior interactions and determine next steps. Predictable
interactions create trust in the product as well as the brand.

Match between system and real world
 The design should speak the users' language. Use words, phrases, and
concepts familiar to the user, rather than internal jargon. Follow real-
world conventions, making information appear in a natural and logical
order.
 The way you should design depends very much on your specific users.
Terms, concepts, icons, and images that seem perfectly clear to you and
your colleagues may be unfamiliar or confusing to your users.

User control and freedom
 Users often perform actions by mistake. They need a clearly marked
"emergency exit" to leave the unwanted action without having to go
through an extended process.
 When it's easy for people to back out of a process or undo an action, it
fosters a sense of freedom and confidence. Exits allow users to remain
in control of the system and avoid getting stuck and feeling frustrated.

Consistency and standards
 Users should not have to wonder whether different words, situations, or
actions mean the same thing. Follow platform and industry
conventions.

Error prevention
 Good error messages are important, but the best designs carefully
prevent problems from occurring in the first place. Either eliminate
error-prone conditions, or check for them and present users with a
confirmation option before they commit to the action.
 There are two types of errors: slips and mistakes. Slips are unconscious
errors caused by inattention. Mistakes are conscious errors based on a
mismatch between the user’s mental model and the design.

Recognition rather than Recall
 Minimize the user's memory load by making elements, actions, and
options visible. The user should not have to remember information
from one part of the interface to another. Information required to use
the design (e.g. field labels or menu items) should be visible or easily
retrievable when needed.

Flexibility and efficiency of use
 Shortcuts — hidden from novice users — may speed up the interaction
for the expert user so that the design can cater to both inexperienced
and experienced users. Allow users to tailor frequent actions.
 Flexible processes can be carried out in different ways, so that people
can pick whichever method works for them.

Aesthetic and minimalist design
 Interfaces should not contain information that is irrelevant or rarely
needed. Every extra unit of information in an interface competes with
the relevant units of information and diminishes their relative visibility.

Help, diagnosis and recovery from errors.
 Error messages should be expressed in plain language (no error codes),
precisely indicate the problem, and constructively suggest a solution.
 These error messages should also be presented with visual treatments
that will help users notice and recognize them.

Documentation and Help
 It’s best if the system doesn’t need any additional explanation.
However, it may be necessary to provide documentation to help users
understand how to complete their tasks.

Contextual inquiry
 Contextual inquiry is a semi-structured interview method to obtain
information about the context of use, where users are first asked a set of
standard questions and then observed and questioned while they work
in their own environments.
 Because users are interviewed in their own environments, the analysis
data is more realistic than laboratory data. Contextual inquiry is based
on a set of principles that allow it to be molded to different situations.
This technique is generally used at the beginning of the design process
and is good for getting rich information about work practices, the
social, technical, and physical environments, and user tools.

Continue
The four principles of contextual inquiry are:
 Focus - Plan for the inquiry, based on a clear understanding of your
purpose.
 Context - Go to the customer's workplace and watch them do their own
work.
 Partnership - Talk to customers about their work and engage them in
uncovering unarticulated aspects of work.
 Interpretation - Develop a shared understanding with the customer
about the aspects of work that matter.

HCI Unit 3.pptx

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