Lecture 5: Reaction time Flashcards
Define reaction time
The interval of time from the presentation of an unanticipated stimulus to the initiation of movement (does not include the time it takes to perform the movement)
What is movement time
the period of time from the end of reaction time to the completion of the movement
What is response time
total time: combination of reaction time and movement time
What is the foreperiod for response time
The interval between explaining the stimulus and presenting the stimulus. (give an interval: you will see a light in 4 seconds)
What is electrical mechanical delay
When looking at an EMG and ask the participant to flex at the elbow, the electrical activity occurs before the mechanical response actually occurs
What are the two types of reaction time
simple reaction time choice reaction time
Define simple reaction time
only one stimulus is present and there is only one response Ex. hearing a start pistol and running a 100 m dash
Define choice reaction time
more than one stimulus is present and each stimulus has a specific response Ex. being presented with 3 different coloured lights that correspond to different buttons you have to press when the light turns on (like guitar hero)
What 5 factors influence reaction time
- Stroop effect 2. Number of stimulus-response alternatives 3. response complexity 4. stimulus-response compatibility 5. Stimulus intensity
How does the number of stimulus-response alternatives influence reaction time
As the number of stimulus-response alternatives increases, choice reaction time increases in a linear fashion. (more choices = longer to react) **Hick’s Law
What is Hick’s Law
When the number of alternatives increases from 1 to 2, the certainty of the outcome decreases drastically, causing a large increase in reaction time. However, if the number of alternatives increases from 9 to 10, the change in certainty is smaller and there is a smaller increase in reaction time
How does the response complexity influence reaction time
The simple reaction time increases because more time is required to organize the motor system to initiate movement. Ex.Henry and Rogers experiment: first just lifted finger, then saw the difference in reaction time when they had to lift their finger and then grab a ball
How does stimulus-response compatibility influence reaction time
An increased compatibility decreases choice reaction time. The greater the natural linkage between the stimulus-response alternatives, the easier it is to process information during the response selection stage. Ex. If there is a mug in front of you and the handle is turned to the left, it would take less time to grab the mug with your left hand.
How does the intensity of a stimulus influence reaction time
The greater the stimulus, the shorter the reaction time Ex. Starting pistol: observed that the runner in the lane closest to the start pistol had a shorter reaction time.
