I would say I generally have an excellent memory with better recall for what is read vs what is said. Not that helps you, but I’m a merely anecdotal case.

Maybe more than recall ask them when they read fiction if they pictures the characters orbjust kind of glaze over during prolong descriptive sections. Do they complain about movie casting? I never picture characters so even if I think a performance is bad, I’m never mad that the actor doesn’t look like how I imagined them.