Researchers want the public to test themselves: https://yourmist.streamlit.app/. Selecting true or false against 20 headlines gives the user a set of scores and a “resilience” ranking that compares them to the wider U.S. population. It takes less than two minutes to complete.
The paper
Edit: the article might be misrepresenting the study and its findings, so it’s worth checking the paper itself. (See @realChem 's comment in the thread).
I took the survey and it gives you two measures - one for correctly identifying true stories and one for correctly identifying fake. If you mark everything fake the results would say you’re too skeptical because you discount real stories as fake. So anything that doesn’t sound hyper partisan should be marked as real, even if you could imagine how it could be fake.