Bang! The starting gun sounds, and you're off! How quickly your brain can process the sound and send a command to your muscles makes a difference! Every hundredth of a second counts in a sprint. In this experiment, we explore auditory reaction time—the interval between hearing a stimulus and reacting with movement. A brief tone plays, and your brain races to process the cue.
Test your auditory-motor response and see how fast you really are!
Humans need to react to many things quickly… a fast-approaching ball to your head (visual), a spider crawling on your neck (tactile), or a loud barking dog (auditory). Does the brain process all these cues the same way? We will find out.
Before doing this experiment, please complete the Visual-Motor Reaction Time Lab.
Using the Human SpikerBox and the Reaction Timer, we will precisely measure reaction times. In this experiment, we focus on auditory reaction time—how quickly your brain responds when you hear a tone. By analyzing the time between the sound cue and your muscle movement, we can gain insight into neural processing speeds and learn about the pathways your brain uses.
Plug the Human SpikerBox into your device via USB, then connect the Reaction Timer using the orange cable. Set the Reaction Timer’s switches to Sound On, LED Off and Random Off (check that the built-in speaker is active or that your headphones are connected).
Hook an arm up to the Human SpikerBox by attaching the two red clips to the stickers on the user’s forearm and the black clip to the sticker on the back of the user’s hand.
Connect the electrode cable to the SpikerBox and ensure the battery is installed correctly. Open the SpikeRecorder software and turn on your SpikerBox.
You are all set up! This task requires two people, so you’ll need a partner. One person will be the experimenter and the other the subject. You will record a simple reaction time—how fast can you react with no distractions?
Have the subject (the one connected to the Human SpikerBox) focus on the Reaction Timer. Explain that their goal is to flex their muscle as quickly as possible in response to an auditory cue. For this experiment, use the green button. When the experimenter presses it, a tone will sound from the built-in speaker. If ambient noise is distracting, the subject may wear headphones (there is a headphone port and volume control on the Reaction Timer).
Start recording in the SpikeRecorder app!
The experimenter will press the button 10 times at random intervals. Vary the timing and cover your fingers so the subject can react only to the sound. When finished, measure the reaction times in SpikeRecorder and calculate the average. Who in your group reacts the fastest?
Compare your results with the class. Compare the average auditory reaction time with the visual reaction time you measured earlier. Which pathway is faster, and why do you think that is?
Draw the path from your ear to your forearm muscle (ear, brain, spinal cord, motor neuron, muscle) beside your drawing from the visual lab, and mark where the two paths differ.
The sensing–processing–responding loop, timed end to end.
MS-LS1-8 Gather and synthesize information that sensory receptors respond to stimuli by sending messages to the brain for immediate behavior or storage as memories.
HS-LS1-2 Develop and use a model to illustrate the hierarchical organization of interacting systems that provide specific functions within multicellular organisms.
2 Developing and Using Models
Draw the path from your ear to your forearm muscle beside your visual drawing and mark where they differ.
3 Planning and Carrying Out Investigations
Time ten reactions to a tone with the Reaction Timer and forearm EMG.
4 Analyzing and Interpreting Data
Compare auditory with visual reaction times.
5 Using Mathematics and Computational Thinking
Measure each reaction time and average them.
6 Constructing Explanations and Designing Solutions
Explain which pathway is faster, the auditory or the visual, and why.
Cause and Effect
Cue type changes latency.
Systems and System Models
Timing the full loop.
Structure and Function
Transduction mechanism sets speed.
LS1.D Information Processing
Receptor → brain → muscle information flow.
LS1.A Structure and Function
System organization.
Performance expectations, crosscutting concepts and core ideas from Hands-On Neuroscience Curriculum Overview, Unit 2, module 2.3, whose core lab this is. The practices are the ones this page asks students to do.
