What is the meaning of "a question of familiarity"

Hi.
I came across this phrase in the following text:
(The text is about sense of direction in humans)

There is nothing in our make-up that tells us which is left or right-- most of our body is in pairs, we have two arms, two legs, etc. If we weren't right-or left-handed, we might well have even more trouble.
Few of us get lost somewhere we know well, but it's not a question of familiarity. In an American experiment, people with very poor of senses of direction were taken to a strange place. The results showed that people with a good sense of direction either remembered a series of clues to help them back to where they started, or they remembered the various turns they had gone through.

What does this phrase mean that i have bolded it in color in the text?