Frequently Asked Questions

Your payment in each experiment generally depends on your decisions and the decisions of the other participants. We do not always provide information about the exact range and expected average payoff for scientific reasons.

Additionally, if you show for an experiment that you are registered for, but the experiment is (for whatever reason) cancelled or you cannot participate, you will get receive a show-up payment of at least Euro 4.-.

Payments are usually carried out via bank transfer, sometimes in cash or in the form of vouchers. We will let you know in the invitation email if the payment is other than cash or bank transfer. Bank transfers may take some time, up to a couple of weeks, after your experimental session, to be processed.

There is no possibility which allows you to cancel your session signup yourself. So please make sure that you are available for an experiment session BEFORE you sign up for it.

However, if you become sick or are not able to attend the session due to some unforeseen circumstances, just reply to your invitation/confirmation e-mail AS SOON AS POSSIBLE and provide reasons. We will then take you off the list.

For most experiments we only invite a random subset out of all participants. We do that to ensure that not always the same people participate in our experiments.

Sometimes, we only invite participants which meet certain characteristics, for example people who have not participated in some particular previous experiments. Thus it is possible that you see experiment sessions in the calendar but are not invited for them. However, if there are not enough participants people registering for these sessions, we will send out invitations to more participants.

Also, make sure that your participant profile is up-to-date, so we know your details and can invite you when you are eligible.

Anyone who is interested in participating in experiments can apply for a subject account. However, to participate in laboratory experiments, you should be able to come to our laboratory situated at the School of Business and Economics in Maastricht, The Netherlands.

Almost all experiments consist of several sessions. You can only sign up for one session of a particular experiment. If you are registered for one session, the other sessions will disappear from the list.

When more experiments for which you are eligible are scheduled, you will receive a new invitation email.

No, never do that. Your information is a crucial element of the experimental research. You will not be allowed to participate in an experiment if your profile or part thereof is found to be incorrect. In case you do not want to provide certain information about yourself, just leave the field blank. Note, however, that providing information will increase the probablility to be invited in experiments which target specific characteristics.

After conducting an experiment we need some time to update the recruitment database. If the experimenter has not filled in the participation data yet, there will be the three question marks as your "show-up" status for the experiment. Once the data is entered, the status will change to either "yes" or "no".

When you receive an email invitation for an experiment, you are not obligated to participate. You can sign up for a session by following the link in the email, choosing a session and confirming your participation. After signing up, you will receive a confirmation e-mail with your session details.

However, once you are signed up for a session, we expect that you show up. For details about "Cancelling a session sign-up" please read the corresponding FAQ.

Unless you are explicitly informed otherwise during the experiment, it may take some time, up to a couple of weeks, to receive your payments. We generally process all payments of an experiment at once after all sessions have been completed. It then takes some time for the experimenter to carefully combine the data, for this information to be checked and send to the financial department, and then for them to authorize payments.

Some experiment will tell you explicitly when you will receive payments. You may even get to choose between different payments at different times. In those cases you can be sure that special arrangements have been made to ensure you will receive the payments exactly when promised.

Occasionally you might also be paid in cash rather than via bank transfer. In those cases you will usually receive payment directly at the end of an experimental session.

The durations of our experiments vary. As of yet, we have had experiments with durations from 20 minutes to 3 hours. Sometimes an experiment consists of multiple sessions in the laboratory (for example a training session in one week and a real experiment in the next). In any case you will be informed about duration etc. before you register for a specific experiment.

We cannot be too specific about the setup and the goals of our experiments, as this could create biases in the data we collect. In general, we test economic and psychological theories of behaviour in markets, bargaining, dilemma situations, risk taking, etc. As a subject, it is best to not concern yourself with our motives for the experiment. Your decisions in the experiments should be authentic to you. At the beginning of an experiment you receive precise instructions with all the necessary information. You can be sure of the following:

• There is no deception in the instructions. You can trust the rules which you receive from the experimenters.

• Your compensation will be paid out as announced at the beginning of each experiment session.

• In general, your decision data is stored anonymously. You will be explicitly and clearly notified beforehand if this is not the case.