Controls & Design Flashcards
What are controls?
Controls are the action after a decision is made
What is the speed of action selection influenced by?
the number of
possible alternative actions that could be
selected.
What is the Hick Hyman Law of reaction time?
A logarithmic increase in reaction time (RT) as
the number of possible stimulus response
alternatives (N) increases.
RT = a +
b Log2 N
What is the formula to predict response time?
Reaction Time = a + bH
More uncertainty, more time
a = simple reaction time (just to respond)
b = additional time for every 1 bit increase in
information
What is the most efficient way to deliver a given amount of information?
give a smaller
number of complex decisions rather than a
large number of simple decisions.
What is Response
expectancy?
We perceive rapidly and accurately that
information that we expect.
What are the principles of response selection?
- Decision
complexity - Response
expectancy - Compatibility
- Feedback
5.Speed accuracy trade off
What is Location compatibility?
Mapping
What is movement compatibility?
moving a lever right
should move the display to the right
What are factors affecting reaction time?
- Age
- Intoxication
- Time of day (especially in auditory response)
- Fatigue
- Practice
What is an example of a Positioning Control Device?
Mouse with a cursor to a target
What affects the movement time of positioning control devices?
movement of the hand or fingers to
the control device
movement of the control device in
some direction.
What is the equation for Fitt’s Law?
- *MT =**
- *a + b log 2 (2A/W)**
MT is movement time
A is the distance (or amplitude) of movement from start to
target center
W is the width of the target, which corresponds to “accuracy”
(2A/W) is the index of difficulty
What is the ID of Fitt’s law?
Index of difficulty
log 2 (2A/W)
What are some implications of Fitt’s law
•Big targets at a close distance are acquired faster than small
targets at long range
•ID provides a single combined measure of two main physical
properties of movement tasks
•ID increases by one unit for each doubling of amplitude and
halving of width
•Positive intercept indicates additive factors unrelated to ID. It
can be related to mechanism of movement and/or selection
(mouse, button,etc)
What is Welford’s ID?
MT =
a + b log <u>2</u> (A/W + 0.5)
How is Welford’s law different than Fitt’s law?
- MT is proportional to the index of difficulty
- Better fit to data than Fitts ’ original
- Possible negative ID
What is Shannon’s ID?
MT =
a + b log <u>2</u> (A/W + 1)
How is Shannon’s Law different from Fitt’s law?
- MT is proportional to the index of difficulty
- Best fit to data
- Positive ID
- Follows from Info Theory