Post on 31-Dec-2015
description
Design & Screen Organization
Some Basic Human Characteristics
• Humans are limited in their capacity to process information.
• People are always learning.
• People use prior learning to support new learning.
• People often learn by doing
• People like to solve problems
• People don’t like unsolvable problems.
Some Basic User Characteristics
• Mental Models– Users are always building models
of their world.– Users don’t mind if something doesn’t
make sense • they build their own model to make it make
sense
– Users prefer simple models • simple and working solution (even it is not
completely correct)
Good & Bad toolbar icons
http://www.vbaccelerator.com/home/Resources/Graphics_Library/index.asp
WHY IS THIS IMPORTANTKnow Your User
• Consider the Individuals using the system (i.e. target user)
• Skill– Computer knowledge, other systems they use,
education, keyboarding skills
• Job – Tasks – Needs– Frequency of use, importance to job, structure of
job, training, culture
• Psychological characteristics– Motivation, patience, expectations, learning style
• Physical attributes– Age, gender,disabilities
Norman’s Design Principles
• The Design principles are based on– Understanding of psychology of users.– Understanding of how people interact with
the environment– Understanding of how people response to
good design and bad design
Norman’s Design Principles
• Providing a good conceptual model• Make things visible• Managing a natural mapping• Providing feedback• Supporting automatic learning• Providing forcing functions
– Utilizing constraints
Conceptual Model
• the underlying understanding of how a technology or device works
Designer’sconceptual model
User’sconceptual model
Gap
System Image
Q: What do large gaps cause?
Three Conceptual Models
Design modelDesigner
Systemimage
System
User’s model
User
Mapping
• Mapping indicates the relationship between the action of the user and the result of the action.
• Natural mapping– The user’s natural understanding of action
results• RED for stop and GREEN for go (cultural
understanding)
Mapping Example
• Present the font choices using the fonts themselves
Times New RomanArialArial BlackCourier NewOld English Univers
Mapping Example
• Function keys – the mapping is somewhat
arbitrary• F3 for CUT and F4 for PASTE ?
– Not a natural mapping!– No memory aids– What happens when you want to
cut but you click on F4 (paste)?
F1 F2
F3 F4
F5 F6
F7 F8
• What mappings are present in a game control such as this joystick?
Forcing Function
• Design that prevents users from taking actions which are inappropriate or which would lead to error– Appliance shut off when opened
• Microwaves• Washing Machines
– Radio buttons• Choose one and one only
Forcing Function
• Good example of a forcing function design:– Menu bar - grays out and prevents the
selection of those items inapplicable to the current context
NewOpenCloseSaveSave as...
Forcing Function
• Lack of Forcing Function– DOS - every command is allowed as long
as it is typed correctly
– del *.*– deletes all files
Feedback
• Gives a user an immediate indication of the result of an action– Pick up the phone
• Hear the tone
– Select text• reverse video for selected text
Affordance
• Make things visible
• Provide indication of how something can be used
Affordances
• What do you need to know?– Which side opens?– Do I push or pull?
• Affordances– Knobs, Plates, Bars
• Size and placement
Affordances
• Buttons– Flat– Shadowed
• Hyperlinks– Plain text– Marked
• Cursor shapes
Automatic Learning
• People automatically connect their actions with screen displays through repetitive patterns of actions (reinforce learning).– A design should provide consistencies that
help the user learn to use the device
File Edit View Insert Format ToolsFile Edit View Insert Format Tools
Automatic Learning
• Good example of Automatic Learning:– user actions always involve same
number of steps, e.g., select object, select general action to perform on object, select specific case of action
– Consistence and standards• If you know how to use one window
application, it will be easy for you to learn another one.
Automatic Learning
• Example of non-use of Automatic Learning :
– Screens which change standard menu item locations from display to display
Three Conceptual Models
Design Model User’s Model
System Image
Visibility
Affordances
Mapping
ForcingFunctions
Autom
ated L
earn
ingActi
on
Feedb
ack
Mismatch between Designer’s & User’s Conceptual Models
• Errors
• Slow
• Frustration
• ...
Knowledge in the Head and in the World
• Knowledge in the world– is the information in the environment
• Knowledge in the head– is the information that stored in memory
• Most of the time we need to combine the two types knowledge to operate things. Why?
Coin Examples
• One Cent Coins– We recognize coins
easily.– But we don’t
remember all the details.
What do you see?
What information do you memorize?
• Location of element• Shape of element• Relationship of element to other elements
on screen• Pictures of icons• Colors
What do you see?
Human Processing of Complex Visual Scenes
• The time it takes to visually understand a scene depends on the number of unique elements that we must visually identify in the scene– If we have already learned the scene, we
record it as one element• Words are recorded as a single element.
– One graphical component many have several unique components.
An Example of a Complex Visual Scene
Control Panel for Desktop Video Conferencing
• Too many elements to learn
• Elements located all over screen – each individual location and relationship to
other elements has to be learned
• Elements not clustered or ordered so that sub-groupings can be learned
Organization of Screen Elements
• Balance• Symmetry• Regularity• Predictability• Sequentiality• Economy• Unity• Proportion• Simplicity• Groupings
Balance
• Equal weight of screen elements– Left to right, top to bottom
Balance
Unstable
Balance
• Left column processed - Right column noted as same
• Both columns need to be understood by visual processing system
Symmetry
• Replicate elements left and right of the center line
Symmetric
Asymmetric
Symmetry
• Left column processed - Right column noted as same
• Both right & left columns processed plus relationship of right to left
Regularity
• Create standard and consistent spacing on horizontal and vertical alignment points
Regular
Irregular
Regularity
• Left column processed - 2 right columns noted as same
• Location & size of each object processed
Predictability
• Put things in predictable locations on the screen
Predictable
Spontaneous
Icon
File Edit View Insert Window Help
Kung Foo
Search for Movies
CancelOK
Enter Keywords:Grasshopper Old blind guy
Icon
File Edit View Insert Window Help
Kung Foo
Search for Movies Cancel
OK
Enter Keywords:Grasshopper Old blind guy
Predictability
• User expects title & menu bar on top of screen
• Visual scene needs to be completely processed - objects not in expected places
Icon
File Edit View Insert Window Help
Kung Foo
Search for Movies
CancelOK
Enter Keywords:Grasshopper Old blind guy
Icon
File Edit View Insert Window Help
Kung Foo
Search for Movies Cancel
OK
Enter Keywords:Grasshopper Old blind guy
Sequentiality
• Guide the eye through the task in an obvious way– The Eye is attracted to:
• bright elements over less bright• Isolated elements over grouped• graphics before text• color before monochrome• saturated vs. less saturated colors• dark areas before light• big vs. small elements• unusual shapes over usual ones
Sequential
Random
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Economy
• Use as few styles, fonts, colors, display techniques, dialog styles, etc., as possible
Economical
Busy
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Economy of visual elements
•minimize number of controls
•include only those that are necessary– eliminate, or relegate others to secondary
windows
•minimize clutter – so information is
not hidden
NNNN
MMMM
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
xxx: ____
MMMM
NNNN
Unity
• Make items appear as a unified whole (for visual coherence)– Use similar shapes, sizes, or colors– Leave less space between screen elements
than at the margin of the screen
Unity
Fragmentation
Proportion
• Create groupings of data or text by using aesthetically pleasing proportions
Square - 1:1 Square Root of 2 - 1:1.414 Golden Triangle - 1:1.618
Square Root of 3 - 1:1.732 Double Square - 1:2
Pleasing Proportions
Simplicity
• Minimize the number of aligned points– Use only a few columns to display screen
elements
• Combine elements to minimize the number of screen objects– Within limits of clarity
Simple
Complex
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Simplicity
• Only four alignments need to be processed
• A total of nine alignments need to be processed
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Simple
Complex
Size:Uniformity:
Height:Width:
Preserve Proportions% of original% of original
Size::Preserve Proportions% of original height% of original width
Redesigning a layout using alignment and factoring
The importance of negative space and alignment
Groupings
• Use visual arrangements to provide functional groupings of screen elements– Align elements in a group– Evenly space elements in a group– Provide separation between groups
• Use additional group elements sparingly– color & borders add complexity
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Simple Grouping
• Similar elements aligned vertically
• Vertical distance between similar objects small
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Boxed Grouping
• Boxes add additional complexity to form
• Spatial arrangement adequate
Background Grouping
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• Color adds additional visual complexity
• Spatial arrangement adequate