Lecture 8B: Controls

Question 1

What are some variables of response selection?

Answer 1

decision complexity
expectancy
compatibility
speed accuracy trade-off
feedback

Question 2

What is the principle of decision complexity?

Answer 2

speed to select an action is influenced by number of possible choices

Question 3

What is Hick’s Law?

Answer 3

humans process information at a constant rate; reaction time is a function of the number of alternatives

Question 4

How can response selection be improved?

Answer 4

minimize choices when time is critical
break tasks into smaller steps
avoid overwhelming users
use progressive onboarding

Question 5

What is the principle of response expectancy?

Answer 5

we rapidly perceive information which we expect; we rapidly execute the actions which we expect are to be carried out

Question 6

What is the compatibility principle?

Answer 6

expected relationship between location of a control and the location or movement of the stimulus or display to which the control is related
Location compatibility (stovetop controls)
movement compatibility (turn wheel left, car goes left)

Question 7

What is the speed accuracy tradeoff?

Answer 7

an individuals willingness to respond slowly and make fewer errors compared to the willingness to respond quickly and make relatively more errors

Question 8

What is Fitts’ Law?

Answer 8

time required for person to move a pointer to a target area is a function of the distance to the target divided by the size of the target; the longer the distance and the smaller the target gets, the longer it takes

Question 9

Why is feedback important?

Answer 9

It helps the user maintain trust in the system, gives transparency

Question 10

What are controls (noun)?

Answer 10

interface elements in human-machine system through which a human transfers mechanical energy or information to the machine for performing automatic functions

Question 11

What are the two types of controls?

Answer 11

Discrete (on off switch)
and Continuous (dimmer switch)

Question 12

What are examples of discrete controls?

Answer 12

Hand/foot push button
Toggle
rotary selector switch

Question 13

What are examples of continuous controls?

Answer 13

knob
crank
wheel

Question 14

When should discrete controls be used?

Answer 14

there is limited number of control states
alphanumeric information must be entered
on-off or yes-no information is required
only small mechanical forces are required or available

Question 15

When should continuous controls be used?

Answer 15

large number of control states involved
operator must exert substantial force to adjust the control
speed of operation is more important than accuracy of control setting

Question 16

What is the control-display ratio?

Answer 16

high control for a low display gives a high ratio

Question 17

What is sensitivity?

Answer 17

ratio of the magnitude of the changes in the controls relative to a display indicator (low ratio, high sensitivity)

Question 18

What is gain?

Answer 18

gain is the measure of the responsiveness of a control (low ratio, high gain)

Question 19

What is the frequency of use principle?

Answer 19

the controls that are used most frequently should be placed in the most convenient locations

Question 20

What is the importance principle?

Answer 20

those controls that are most important should be located at convenient locations

Question 21

What is the sequence of use principle?

Answer 21

if several controls must be operated in sequence, they should be located next to each other

Question 22

What is the control-display compatibility principle?

Answer 22

control devices should be configured spatially similar to their associated displays.