If you have struggled to interact with people who are different than you, that is also part of the human experience, not something we need to devise measurements for.
IF is a tool mostly to remind high IF people to cherish the value of both real and imaginary experience, and a tool to help people who dwell mostly in either realm to respect each other. If a high IF person forgets to respect the real, he's liable to forget his wedding. If a low IF person forgets, he's liable to miss out on the wonder and value of abstract thought.
To someone, my responsibility might be answering the doorbell quickly when Amazon drops off a package.
To another, it might be how responsive I am to email.
These are in conflict, and sometimes it’s worth missing an Amazon package to finish an important email.