Exam 1 Flashcards
What is User-Centered Design? What are the three activities or principles that must be
employed for a process to be considered a UCD process?
- Iterative design
- Early focus on users and goals/tasks
- Constant evaluation
Iterations in a UCD process are supposed to be quick. Why?
- Can do more iterations = try more ideas and refine UI more
- Trying more ideas helps avoid design inertia
The radial dimension of the spiral corresponds to the cost of each iteration step
(fidelity/accuracy).
How many chunks of info can a human store in working memory at once?
5 to 9
7 +/- 2
What is meant by recognition versus recall? Give an example.
It is easier for a user to recognize the name of an object than it is for them to
recall the object’s name from memory. For example, it is easier to recognize a
particular file in a directory hierarchy using Windows Explorer than it is to have
to recall the exact directory path and filename using a command line interface.
What is Fitt’s Law (in plain English)?
Fitt’s Law says that the time to acquire a target is proportional to the distance
from the target and inversely proportional to the size of the target. Said another
way, it is easier to hit objects that are larger and closer to an origin point.
What are two implications for design that can be
derived from Fitt’s Law?
- Use large, visible controls
- Place them in a location where they’re likely to be used based on the task
- Targets at the edge of the screen are easier to hit
What are some implications for design based on what we know about the human eye?
- Use contrasting foreground and background colors
- Use extreme color differences to convey information in peripheral displays
- Avoid use of small blue text
- Be wary of using colors to convey statuses in UI’s (consider color-blindness)
What percentage of males and females have some form of color-blindness?
Males: 8%, Females: less than 1%
What is the system model?
How the system actually works (internal workings)
What is the interface model?
How the system presents information to the user; it shields the user from the
system
What is a mental model?
How the user thinks the system works
What is a disadvantage of a command language?
Requires recall over recognition
What is affordance?
How an object’s visual representation conveys to a user how it can be used
What are transfer effects? Give an example of positive transfer effects. Give an example
of negative transfer effects.
How previous knowledge aids or hinders learning a new interface
Positive: Windows to MacOS, or vice versa
Negative: Removing a floppy disk in MacOS (dragging to trashcan)
Why are natural mappings hard to achieve? Give an example.
Often, controls can’t be oriented the same way as the things they control. An
example is a light-switch panel. It is difficult (if not impossible in some cases) to
orient the light-switches in the same way the lights themselves are positioned
Why do metaphors end up being “broken” in user interfaces?
Hard to select; too much of a stretch
Deceptive
* * “It looks like a book, but can I write in the margin?”
Constraining
* * Example: strict adherence to desktop metaphor wouldn’t scale
Breaking the metaphor
* * At some point, UI must have more functionality than its real-world counterpart and metaphor must be broken
What are design heuristics?
They are principles that distill out properties of good design. They help identify
characteristics that are common to successful user interfaces.
Let’s say we design a user interface, build a corresponding paper prototype, and attempt
to scrutinize its relative simplicity. How can we tell if a particular design element is
essential or non-essential?
Remove the design element in question from the paper prototype. Test the
prototype with real users and see if the design falls apart.
Consider the following visual variables we mentioned while talking about contrast in
graphic design. Identify how the Google search engine uses these visual variables to
highlight sections of their search results (also shown below).
Title of each result: size, value, hue – uses multiple variables for better contrast
Search term (throughout): value
URL of result: hue
Book results: position (indented), shape (books image), hue
Title of each result: size, value, hue – uses multiple variables for better contrast
Search term (throughout): value
URL of result: hue
Book results: position (indented), shape (books image), hue
