There are two types of Figure-Ground Task--Aural and Statistical.
There are two types of figure-ground task. They are really opposites ends of a continuum. At one end is an Aural figure-ground task and at the other is a Statistical figure ground task.
An Aural figure-ground task is one in which the figure and the ground are unmistakably different. It never fails, when you are in a class and the instructor says "Listen carefully because this will be very important·" that a loud lawn mower and/or a leaf blower will pass by the window.
To say that it is very difficult to concentrate under such conditions is to have commented on an aural figure-ground task. Or worse yet, someone with a nasal-dripping cold (as demonstrated in the Notes) sits behind you in class with much audible sniffling etc.
NOTE: See if you can ignore this ground (noise).