How to run: cerebJND (pitch OR formant)

How to run cerebJND, both f0 and f1 modes. Part of cerebellar battery 2022-2023

Special circumstances: part of battery

This experiment is part of the cerebellar battery run in 2022-2023. 

  • Patients at UW: Both f0 and f1 are in session 2
  • Controls at UW: Both f0 and f1 are in session 1
  • Patients at UCSF: Both f0 and f1 are in session 2

In this battery, participants come in for multiple sessions and do multiple experiments in a row. As such, this is a bare bones document on how to run the experiment. Procedures for consent, hearing screening, awareness surveys, general equipment set up, and payment are not included in this document. See the documents below for how these procedures are implemented in this multi-study session: 

  1. Protocol for cerebellar battery: controls
  2. For patients

What's special about this experiment

This is a perceptual experiment that first records tokens from the participant, and then uses those tokens as the basis of the perceptual stimuli. 

This code can run in either f0 mode (pitch perception) or f1 mode (formant perception). You will have to specify which one at the beginning of the experiment. 

Prepping for participant

Participant will need: 

  1. Microphone (for recording initial tokens)
  2. Headphones --- do not put the headphones on until after the participant is done recording tokens. 
  3. Keyboard (for responses) 

Pre-experiment instructions

Tell the participant: "In this experiment there will be two sections. In the first section, you will say {ba / bed} a few times and we will record your speech. In the second section, you will hear three different tokens and say which are most similar to each other. There will be a short pause between sections while I get things set up. Do you have any questions?" 

Stimulus setup

Type run_cerebJND_expt in the Matlab command window and press enter. 

You will be prompted to enter in either f0 or f1.

  • If you are doing PITCH perception, type f0.
    • You will be prompted to enter which pitch shifting algorithm you want. [[ANNEKE: WHICH ALGORITHM TO USE IN WHAT CIRCUMSTANCES?]]
  • If you are doing FORMANT perception, type f1. 
  1. The participant will be prompted to say “ba” (f0) or "bed” (f1) for five trials. They can just talk normally. 

  2. After they are done recording the tokens, you will get the option to either re-record (if you think that none of the trials were a good representative of the participant's "clean" speech), or choose the trial that you want to base the continuum on. 

  3. If you “move on,” then the script will automatically trim each trial to the speech portion and play each through your computer’s default speakers. (If you want to listen with headphones, I recommend setting your Windows default sound output device to the desktop computer, and then plugging in headphones.)

  4. If one of the trials seems like a good candidate for creating the continuum, enter that trial's number (1-5) in the command window and hit enter. 
    1. If you want to hear them all again, press 9
    2. If they all actually sound bad, press any number between 1 and 5, then type "yes", then type "redo" when given the option

  5. Once you pick a trial that sounds okay, you will see a waveform showing you how the automatic trimming was done. You cannot change the trimming, but it might inform your decision of whether that’s a good trial or not. If it looks good, say Yes. The trimming should include the entire vowel. 

  6. Now, you’ll be given a final choice about if you want to keep that as your final continuum basis, or if you want to record new speech tokens. (redo/move on)
  7. Once you move on, the computer will begin generating tokens with slightly different f0 or f1. Tell the participant: "Okay, you can relax for a few minutes while we generate the sounds that will be used in the next section. This may take a couple of minutes." 

Perceptual staircase (main task) 

After the stimuli have been generated, you will move onto the actual perceptual section of the participant. Tell the participant: 

"In this section, you will hear three different tokens. Your task is to say if the second token is most like the FIRST token, or the LAST token. If the second token is most like the FIRST token, press F. If the second token is most like the THIRD token, press J. Do you have any questions?" 

Answer questions, then tell the participant: "First we will start with a practice round just so you can get used to the task." 

The practice phase has very large stimulus differences and will take about 1 minute (10 trials). 

If they are okay to move on, tell the participant: "We will now move onto the main section. The task may get very difficult and you might not be sure what is the right answer. That is okay, just take your best guess. This will take about 10 minutes." 

Start the main task. It maxes out at 100 trials or 32 reversals, whichever comes first.

If Matlab crashes during the experiment

As of 10/21/2022 there is no remedy for a crashed experiment. 


Keywordshow to run, cerebellar, JND, perception, ptb, formant, pitch, staircase   Doc ID122061
OwnerRobin K.GroupSMNG Lab Manual
Created2022-10-21 18:02:03Updated2022-10-21 18:30:07
SitesSpeech Motor Neuroscience Group
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