Human Computer Interaction Assignment

1. HCI ASSIGNMENT 3
1. Match Experience & Expectations
When using a product or service for the first time there is likely to be an element of
learning needed to get to grips with it. This learning curve can often be an
uncomfortable experience especially if the proposition doesn‟t feel familiar.
By matching the sequence of steps, layout of information and terminology used with the
expectations and prior experiences of the user the friction and discomfort of learning a
new system will be reduced.
Matching your audience‟s prior experiences and expectations is achieved by using
common conventions or UI patterns.
2. Consistency
As well as matching people‟s expectations through terminology, layout and interactions
the way in which they are used should be consistent throughout the process and
between related applications.
By maintaining consistency users learn more quickly, this can be achieved by re-
applying in one part of the application their prior experiences from another.
An added bonus of keeping elements consistent is that you can then use inconsistency
to indicate to users where things do not work the way they might expect. Breaking
consistency is similar to knowing when to be unconventional as mentioned above.
3. Functional Minimalism
“Everything should be made as simple as possible, but no simpler.”
The range of possible actions should be no more than is absolutely necessary.
Providing too many options can detract from the primary functions and reduce usability
by overwhelming the user with choices. To achieve the zen of „functional minimalism‟:
Avoid unnecessary features and functions
Break complex tasks into manageable sub-tasks
Limit functions rather than the user experience
4. Cognitive load

2. Cognition is the scientific term for the “process of thought”. When designing interactions
we need to minimise the amount of “thinking work” required to complete a particular
task. Another way of putting it is that a good assistant uses their skills to help the master
focus on their skills.
We need to understand how much concentration the task requires to complete it and
create a user interface that reduces cognitive load as much as possible. A good way to
reduce the amount of „thinking work‟ the user has to do is to focus on what the computer
is good at and build a system that uses the computers skills to the best of its abilities.
Remember that computer are good at:
Maths
Remembering things
Keeping track of things
Comparing things
Spell Checking and spotting/correcting errors
In User Experience terms engagement measures the extent to which a consumer has a
meaningful experience. An engaging experience is not only more enjoyable, but also
easier and more productive. As with many things engagement is subjective so the
system your designing must engage with the desired audience; what appeals to a
teenager is not necessarily what their grandparent would also find engaging. Beyond
aligning with the appropriate users, control achievement and creation are key.
The user should feel like they are in control of the experience at all times, they must
constantly feel like they‟re achieving something and also be able see the results through
positive feedback or alternatively feel like they‟ve created something.
In his book „Flow‟, MihalyCsikszentmihalyi describes a state of optimal experience,
where people are so engaged in the activity they‟re doing that the rest of the world falls
away. Flow is what we‟re looking to achieve through engaging interactions. We should
allow users to concentrate on their work, not on the user interface. In short keep out of
the way!
6. Functional Layering
The Pareto principle (also known as the 80-20 rule), in the context of interaction design,
is the rule that 20% of the functionality is used 80% of the time. Therefore we should
make the most common or important functions easiest to find. We can do this by hiding
or reducing the prominence of infrequently used or advanced functions.
Look for functions that are not essential to the core tasks, or which are shortcuts
for advanced users.

3. Consider introducing default settings and preset choices for new users or people
who either don‟t wish to or aren‟t experienced enough to access advanced
functionality.
Functional layering allows experienced users to access advanced functionality easily
without hindering beginners. The idea is that as a user progresses they will naturally
discover how to access such features without being overwhelmed early on.
7. Control, Trust &Explorability
These three elements are fundamentally important to any system. If users feel in control
of the process they will be more comfortable using the system. If the user is comfortable
and in control they will trust that the system will protect them from making
unrecoverable or unrecognised errors or from feeling stupid. Trust inspires confidence
and with confidence the user is free to explore further.
8. Error Prevention, Detection & Recovery
The best way to reduce the amount of errors a user makes is to anticipate possible
mistakes and prevent them from happening in the first place. If the errors are
unavoidable we need to make them easy to spot and help the user to recover from them
quickly and without unnecessary friction.
Error Prevention
Prevent errors by:
Disabling functions that aren‟t relevant to the user
Using appropriate controls to constrain inputs (e.g. radio buttons, dropdowns)
Providing descriptive, clear instructions and considering preemptive help
As a last resort provide clear warning messages
Error Detection
Anticipate possible errors and provide feedback that helps users verify that:
They‟ve done what they intended to do
What they intended to do was correct
Its important to remember that providing feedback by changing the visual state of an
object or item is more noticeable than a written message.
Error Recovery
If the error is unavoidable provide clearly marked ways for the user to recover from it.
For example provide “back”, “undo” or “cancel” commands.

4. If a specific action is irreversible it should be classed as critical and you should make
the user confirm first in order to prevent slip ups. Alternatively you can create a system
that naturally defaults to a less harmful state. For example if I close a document without
saving it the system should be intelligent enough to know that it is unlikely that I
intended the action and therefore either auto-save or clearly warn me before closing.
9. Mousing
In my daily interactions „mousing‟ is becoming less of an issue as I begin to rely more
on touch screen interfaces such as my iPhone and iPad. However, in the classic
desktop environment „mousing‟ relates to the ease in which you are able to move
between controls, which is described best through Fitts‟ law.
“The time required to click an object is proportional to the distance and inversely
proportional to the object size.” Fitts‟ law
Fitts‟ law is a model of human movement in human-computer interaction (HCI) and
ergonomics which predicts that the time required to click an object is proportional to the
distance and inversely proportional to the object size.
With key functions or sequential mouse-operated controls we need to maximise the size
of the controls and minimise the distance between them. This not only improves
efficiency but in certain instances can reduce the risk of error.
Consider what the most common or typical mouse movements will be on each
screen.
Where possible, place elements that will be used together in close proximity to
each other.
Be particularly conscious of transactions that require a combination of mouse
and keyboard controls. Consider ways to optimise for both styles.
10. Affordance
Affordance is the quality of an object that allows an individual to perform an action, for
example a standard household light switch has good „affordance‟, in that it appears
innately clickable. In short the physical properties of an object should suggest how it can
be used. In the context of user interfaces, affordance can be achieved by:
Simulating „physical world‟ affordances e.g. buttons or switches
or keeping consistency with modern web standards or other interface elements
e.g. underlined links or default button styles.
11. Hierarchy of Control

5. The hierarchy of influence between elements should be clearly apparent. Generally,
controls which affect an object, should be grouped with the object, such as zoom
controls on a map.
Controls which influence a group of objects should be associated with the entire group,
forming a hierarchy.