Lecture 1.5: Reaction Time

Question 1

What is Reaction Time (RT)?

Answer 1

• The time it takes for all 3 stages of processing to occur
• A measure of the speed of processing
• Does NOT have movement

A component of response time (Response Time = Reaction Time (RT) + Movement Time (MT))

Question 2

What time intervals make up response time? Give an example of response time in real life

Answer 2

Reaction time and movement time.

Question 3

What is movement time?

Answer 3

The period of time from the end of RT to the completion of the movement

Question 4

What is foreperiod?

Answer 4

Between warning stimulus and the actual stimulus

Example track coach puts his arm up (warning stimulus) then puts his hand down to indicate start of running (actual stimulus)

Question 5

Why have a variable foreperiod?

Answer 5

To keep things unpredictable and it reduces the anticipation effect

Question 6

What is the premotor period and what is the motor period? What are they subcomponents of?

Answer 6

Premotor period: from the actual stimulus to the emg activity. Includes stimulus identification and response selection.

Motor period: EMG activity to start of movement in movement time. Includes response programming until the start of actual movement. No movement but emg (skeletal muscle activity) is present.

They are subcomponents of reaction time

Question 7

T or F: Reaction time provides insight into the 3 stages of processing

Answer 7

True

Question 8

T or F: Hick’s Law States that as S-R alternatives increase, CRT increases

Answer 8

True

Question 9

T or F: SRT increases as response complexity decreases

Answer 9

False

Question 10

T or F: CRT increases as S-R alternatives become more compatible

Answer 10

False

Question 11

SRT decreases as stimulus intensity increases or decreases?

Answer 11

Increases

Question 12

What are the 2 types of testing in reaction time and describe them?

Answer 12

1. Simple reaction time
   * 1 stimulus and 1 response i.e.100. sprint start
2. Choice reaction time
   * More than 1 stimulus, and with it each has its own specified response i.e. 3 different lights (red, green, blue), whatever light pops up you have to press its associated key

Question 13

List the 5 factors that influence reaction time

Answer 13

1. Stroop effect
2. Number of stimulus-response alternatives
3. Response complexity
4. Stimulus-response compatibility
5. Stimulus intensity

Question 14

What is the stroop effect and what stage(s) of processing does it affect? Give an example of stroop effect

Answer 14

• The time delay due to parallel processing of competing streams/stimuli
• Difficult to identify the colour when the word is a colour, competing streams
• Delays reaction time

Stage most involved is stage #1 due to two streams of information coming in, delays reaction time as it takes longer to identify the stimuli you want because the other is competing for a response as well

Not stage #2 because after you set on the stimuli it is easier to generate a response and then program the response

Question 15

How does the number of S-R alternatives affect reaction time? What stage(s) does it affect? Give an example.

Answer 15

As the number of S-R alternatives increase, choice reaction time (CRT) increases in a linear fashion

More stimulus response options = more information needed to process = choice certainty ⇓ = total reaction time ⇑

Example: Imagine 10 lights now instead of 1, each with its own unique response = decreases choice certainty and increases reaction time in the stimuli identification stage and mostly in the response selection stage

Question 16

T or F: Increasing S-R alternatives from 1-2 induces a higher change in RT than increasing S-R alternatives from 4-5

Answer 16

True. Due to %’s, from 1-2 is a 100% increase, 4-5 is a 25% increase

Question 17

How does the complexity of response affect reaction time and what stage of processing does it affect? Provide examples?

Answer 17

The complexity of the response programming is high = ⇓ simple reaction time (motor programming stage needs more time to program the complex movement)

i.e. finger lift programming vs finger lift, reach and hit ball, reach back to start position, reverse and strike a suspended ball

Affects stage #3

Question 18

How does stimulus-response (S-R) compatibility affect reaction time and what stage of processing does it affect? Give examples.

Answer 18

Higher natural linkage in stimulus and response = movement processing flows better = ⇓ in reaction time

i.e. playing minecraft on regular xbox controls, then you come back on after your brother was playing on it and the controls are inverted. It will take you longer to react because you are selecting now the appropriate response.

Affects Stage #2

Practice can overcome these unnatural linkages, keep playing minecraft on inverted controls and you will get comfortable

Question 19

How does the intensity of a stimulus affect reaction time and what stage of processing does it affect? Give example

Answer 19

⇑ Sound level = ⇑ reaction time / response time

i.e. swimming race, distance each lane is from pistol

This affects stage #1, identify the sound then you know the pre-programmed response.

Sometimes a very intense stimuli can increase RT due to fear/confusion

Question 20

What is the idea behind Hick’s Law

Answer 20

When the number of S-R alternatives increases from one to two, the increase in reaction time is relatively large

• 190ms (SRT) to 300ms (CRT)

However, when the # of choice alternatives increases from nine to ten, the increase in RT is relatively small

• Maybe only a 20ms increase