FAQ - Frequently asked questions


General questions about study participation

Is there compensation for effort?

You'll receive monetary compensation of 9.00 € or 10.00 € per hour for your efforts (depending on the study).

How safe is it to participate in studies with regard to COVID-19?

The MPI for Human Cognitive and Brain Sciences has compiled a comprehensive list of protective hygiene measures to protect study participants and staff in the best possible way during experiments. If you have any questions, please do not hesitate to contact us.

Do I have insurance coverage as a participant in a study?

Test participants are subject to insurance coverage for legal claims of civil law contents in the context of the business liability insurance of the Max Planck Society.

I have already participated in a study. How can I participate in other studies?

Please fill out our study registration form (link). We will contact you as soon as there is a study suitable for you. You can also search for one or more studies directly at https://www.cbs.mpg.de/aktuelles/studienteilnehmer. We look forward to hearing from you.

As a participant in a study, do I have to pay special attention to anything, e.g. not eat any food before a certain study?

As a rule, you can go about your everyday life as usual. The study director will give you information in advance about what to observe on the day of the study. For a few studies it may be necessary to fast in the morning, e.g. for a blood sample. You will always be informed of this separately.

My child is taking part in a study. Can I be present during the study?

We will always make sure that you can be near your child. The procedure will be explained to you and your child in detail in advance.

How safe are my data?

We assure you that your data will be treated confidentially, stored exclusively within the MPI-CBS, and not passed on to third parties. Only a clearly defined group of MPI-CBS staff members responsible for recruiting study participants will have access to the data. The data is used exclusively for the purpose of inviting you to participate in scientific studies. You have the option, at any time, to have your data in the database permanently deleted. To do so, please write an e-mail with the subject "Delete" to the address:

How can I revoke my declaration of consent?

Please write an e-mail with the subject "Delete" to the address: .


Questions about the research methods

What is an imaging procedure (MRI)?

MRI uses strong magnetic fields to provide high-resolution images of the anatomical structure of the brain as well as detailed pictures of the brain functioning. MRI is a non-invasive imaging procedure that has been used in medical diagnostics for more than 30 years. The examination is painless and harmless.

What should I consider before the MRI scan?

Due to the strong magnetic field and the relative confinement in the MRI machine, a certain group of people cannot be examined with the MRI, e.g. if:

  • there is metal that cannot be removed from the body (e.g. bone screws, joint prostheses, retainers, or braces)
  • tattoos on the neck or genital area, or tattoos larger than 20 cm in diameter are present.
  • claustrophobia is present

If you are interested in MRI examinations, possible contraindications will be clarified in advance.

What are electrophysiological procedures (EEG, MEG)?

Electroencephalography (EEG) is used to measure the electrical voltage fluctuations that occur during brain activity. This is done via measuring surface electrodes on the head, which are provided with contact gel and mounted in a cap. Magnetoencephalography (MEG) measures magnetic fields above the surface of the head that are generated by the synchronous activity of neurons in the brain. These very weak magnetic fields are registered with special magnetic field sensors, which are arranged helmet-like in the MEG device. EEG and MEG are non-invasive and harmless examination methods that have been used in clinical and/or scientific everyday life for decades. There are no special restrictions for participation in EEG or MEG studies.

What are stimulation methods?

Transcranial magnetic stimulation (TMS) is a method that uses strong magnetic fields to stimulate or inhibit areas of the brain in order to simultaneously observe changes in perception and behavior. The stimulation is done by means of a magnetic coil through the intact skull. TMS has been used for more than 30 years in both research and routine clinical diagnostics. According to the current state of science, there are no known harmful short- or long-term side effects with tMS. tDCS is a procedure with which brain activity in areas of the human brain can be influenced by means of electrical stimulation. tDCS uses a low, subthreshold direct electrical current that is hardly noticeable to the test persons. The stimulation takes place through the skull. tDCS is a well-tolerated, non-invasive, and painless procedure with very few side effects. Due to the intrinsic stimulation by strong magnetic fields or electrical stimulation, a certain group of people cannot participate in tMS examinations, e.g. if:

  • metal or electronic devices are present in the body (e.g. intracranial metal parts, implanted heart or brain pacemakers)
  • you have a seizure disorder (epilepsy)
  • regular headaches or migraines are present

If you are interested in TMS and/or tDCS examinations, possible contraindications will be clarified in advance.

What do you use psycho-physiological procedures (e.g. ECG, CPR, pain studies, blood tests) for?

Electrocardiography (ECG) is used to record the activity of the heart. For this purpose, some electrodes are stuck on the body (e.g. back or chest). Skin conductance (SPR) and pulse are used, for example, to examine the processing intensity of tasks or stimuli. For this purpose, two electrodes are attached to e.g. two different fingers (SPR) or an infrared finger clip (pulse). All methods are harmless and a standard procedure that has been used in clinical and/or scientific life for decades. There are no special restrictions for participation in studies using ECG, SPR or pulse.

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