Experiment: Clocking the Brain: Choice Reaction Time

Clocking the Brain: Choice Reaction Time

Can you measure the speed of cognitive processes with just our muscles? We will find out! In this experiment we will measure how fast it takes you to make a decision!

What Will You Learn?

The difference between simple and choice reaction times.
How adding a second stimulus affects reaction time speed.
How cognitive processing can be measured from motor responses.
Data analysis techniques by comparing results with the Visual-Motor Reaction Time experiment.

Background

We make decisions every day. But they seem so abstract. You may think there is no way to scientific way to measure this. But we will soon see, it is easy (if you do some math).

Be sure to complete the Visual-Motor Reaction Time experiment before attempting this test, as it provides the foundational skills needed, as well as the data we need for our calculations!.

Procedure

Setup

Connect the Human SpikerBox and Reaction Timer as before. Confirm that both the green and red buttons operate the green and red LEDs.

Attach the electrodes to the subject(s) as in the previous experiment. Use the same arm that was used for data collection.

Open the SpikeRecorder software and verify that the system receives inputs from both stimuli are showing up on the screen.

Experiment

You’re ready to test your Choice Reaction Time! The subjects—already familiar with the reaction task—must react only when the green LED lights up. Ignore the Red! If the red LED lights up, the subject must remain still.

Subject(s) should flex their arm as quickly as possible to the green LED. Just like last time, we will be measuring the response to a green light. That part is 100% the same!

The experimenter will conduct 20-30 trials, 10 trials of which will be the green LED (don't go too fast!). Be sure to mix in the red LEDs in a random order so they wont be able to predict when it is coming or what color!

Record all reaction times using the SpikeRecorder App and note any incorrect responses.

Compare your data with your colleagues to see how the added decision-making affects speed.

Results & Analysis

Review and compare your reaction times for both valid (green LED) trials. Analyze how the added decision step influences your overall speed. Remove any false starts or missed signals, and compare these findings with your Visual-Motor Reaction Time results.

How can you measure how long it took to decide what color the LED was?

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