Rhythm Adaptation Experiment Instruction

Introduction:

Goal: Sensorimotor synchronization (SMS) is the rhythmic synchronization between a timed sensory stimulus and a motor response. In this experiment we will have you performing an SMS task of hearing/watching a tempo changing recurrent auditory/visual stimulus and response to it by generating a corresponding sequence of click sounds.
Task: You are supposed to generate a one-to-one response in synchronization with the auditory/visual sequence of clicks/flashes. Your sensory act is to listen or watch the sequence generated by a computer application and your motor response will be your hand-clapping, finger-tapping or hitting a given weight against a pad. Your results will be analyzed to discover how humans synchronize with a perceived changing rhythm under different circumstances. We are particularly seeking if different subjects act considerably different given their individual properties (musical background, age, gender, etc).

Anonymity: Your results with remain anonymous and will not be reported, published anywhere with your name; however, you can ask the test holders to give you your own analyzed plots in case that you want to know more about your characteristics of rhythm-adaptation.
Safety: Basically there will be no harm caused by such tests, however, if you have a background in epileptic seizure or any neural disorder you may please inform the experimenters. Besides your arm/hand/fingers that you will use during the test must be in a healthy condition.

Compensation: The experiment will be done in two days. For each day, a subject needs to perform a 45 minutes trial and at the second day takes two cinema tickets for accomplishing both trials.

Instructions for the first day experiment (Auditory Rhythm Adaptation):

  1. The test is done in an anechoic chamber (an acoustically dead room) that absorbs sound perfectly. The pyramid-shaped pieces on the walls and floor are covered by carbon and iron, so you may watch your clothes not to get dirty if you lean on them.
  2. Please switch off your phone and take off your watch, wristband, etc. Piercing is fine. The idea is that you should feel comfortable during the test and do not attach considerable weight to your hand. Since the room’s floor is covered by a grid, it will be very hard to find your small accessories back if they are dropped from your hand or the experiment test. So you may hand them to the experimenters before you start the required task.
  3. Your task is to generate a one-to-one response in synchronization with the auditory sequence of clicks you hear.
  4. To make the click sound, you can choose your dominant hand, in case that you are left-handed or right-handed. But you must use the same hand during the whole session.
  5. You will be blindfolded. Please relax, sit comfortably and focus on the stimuli during the each session. The test needs your 100% attention.
  6. There are three different motor tasks and you will be told by the experimenters by which mean you generate the click sounds:
    • For the finger-tapping sessions, you are asked to use the wrist to lead an abrupt, pulsed action and to suddenly release the downward force on the laptop computer keyboard’s space button.
    • For the clapping sessions, you use a take a figure-to-palm position of the right hand relative to the left hand (or vice versa) forming a right angle with a natural curvature.
    • For the weight-hitting sessions, you will be given a metal cylinder (a group of them taped to each other). Your task is holding them vertically in your preferred hand and to make the click sound by hitting the weight against a metal pad. Please keep your elbow fixed on the experiment table and do not twist your wrist to hit the pad.
  7. Each trial will take up to 45 minutes and has three session
  8. Each session lasts 13 minutes and is divided into three stimuli sequences of 4 minutes each, with two short breaks. You need to remain seated during a session but you can take a longer break when the experimenter gets back to you, once you finish a session.
  9. In each 4-minute sequence of auditory stimuli you will listen to a series of a single piano note via a microphone. You are asked to follow the changing rhythm and simultaneously generate a click sound in synchronization with any click you hear. This means that if the tempo changes you should adapt to it as soon as you can.
  10. If your task is not clear, please feel free to ask the experimenter before you start.

Instructions for the second day experiment (Visual Rhythm Adaptation):

  1. The test is done in an anechoic chamber (an acoustically dead room) that absorbs sound perfectly. The pyramid-shaped pieces on the walls and floor are covered by carbon and iron, so you may watch your clothes not to get dirty if you lean on them.
  2. Please switch off your phone and take off your watch, wristband, etc. Piercing is fine. The idea is that you should feel comfortable during the test and do not attach considerable weight to your hand. Since the room’s floor is covered by a grid, it will be very hard to find your small accessories back if they are dropped from your hand or the experiment test. So you may hand them to the experimenters before you start the required task.
  3. Your task is to generate a one-to-one response in synchronization with the visual sequence of flashes you observe.
  4. To make the click sound, you can choose your dominant hand, in case that you are left-handed or right-handed. But you must use the same hand during the whole session.
  5. You need to stare at the flashing screen during a session. Sit comfortably and be prepared for focusing on the stimuli. The test needs your 100% attention.
  6. There are three different motor tasks and you will be told by the experimenters by which mean you generate the click sounds:
    • For the finger-tapping sessions, you are asked to use the wrist to lead an abrupt, pulsed action and to suddenly release the downward force on the laptop computer keyboard’s space button.
    • For the clapping sessions, you use a take a figure-to-palm position of the right hand relative to the left hand (or vice versa) forming a right angle with a natural curvature.
    • For the weight-hitting sessions, you will be given a metal cylinder (a group of them taped to each other). Your task is holding them vertically in your preferred hand and to make the click sound by hitting the weight against a metal pad. Please keep your elbow fixed on the experiment table and do not twist your wrist to hit the pad.
  7. This trial will take up to 45 minutes and has three sessions:
  8. Each session lasts 13 minutes and is divided into three stimuli sequences of 4 minutes each, with two short breaks. You need to remain seated during a session but you can take a longer break when the experimenter gets back to you, once you finish a session.
  9. In each 4-minute sequence of visual stimuli you will watch a black screen that continuously flashes in white. The flashing light changes its frequency and you are asked to follow the visual rhythm and simultaneously generate a click sound in synchronization with any white flash you observe. Each white flash takes 300mS and is long enough to perceive but try to make the sound immediately when the screen becomes white, not when it turns back to black.
  10. If your task is not clear, please feel free to ask the experimenter before you start.

Please contact i@nim.ir in case that you are interested in taking part in the experiment. Thanks for consideration! 🙂

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