How can you be certain? They keep making reference to the second and fourth fingers. The forefinger by definition is the first finger.
The nut who carried out the study based it on tests of psychology students. This is an aberrant, crazy section of the general population.
It's a stupid article anyways about a stupid study probably funded by my money approved by stupid bureaucrats.
Think "digit" instead of finger and you can follow it (with the thumb being the first digit).
Finger #1 is the thumb.