From the DoE webpage:
Dr. David Dickinson and Dr. Todd McElroy are screening potential subjects for research studies in the general area of sleep and decisions. This screening requires you to provide certain demographic information. If you are selected, you become eligible for participation in future cash-compensated research experiments. Please note that you must complete the entire questionnaire to be eligible for selection. The estimated time to complete this questionnaire is about 6 minutes. Completion of this questionnaire does not guarantee your selection and participation in a future experiment, it only provides the researchers authorization to place your e-mail address in a recruitment pool for future consideration. If selected, you will be contacted at a future date.
More information from Dr. Dickinson:
The survey should only take 5-6 minutes, so it is really short, but subjects who do this online survey become eligible for recruitment for some cash compensated experiments I’m starting to do this semester. In other words, just registering with the online lab recruitment system does NOT make them eligible for these experiments I’m doing, so students will hopefully take a few minutes to click both links. Additionally, you can highlight that there will be a drawing at the end of the semester for a prize of $100 worth of educational supplies. So, 6 minutes of their time puts them into a drawing for $100 of educational supplies and, more importantly, makes them eligible to recruitment to some cash-compensated experiments for which doing this survey is a prerequisite.