We have used the analogy of firefly blinks at our house for many years now…
Fireflies blink in simple patterns to identify to each other who is of the “same kind” for mating. This figures prominently in one of the Madeline L’Engle books, I think Arm of the Starfish, when one (human) character tries to trick another into believing she is of the same kind as him. His sister uses the firefly image to warn him that the girl is not as she seems. Because we have made choice-of-wife a large topic in our family since the boys were small, the question of whether a girl has the right number of firefly blinks has been confined to romantic caution. I think the analogy applies more generally for the tribes, however. People get a sense of how many blinks you have.
The best story we have of this is (of course) Benjamin’s. Years ago he was quite taken with a girl at youth group, and to understand each other better, they agreed to read what had been the other’s favorite book as a child. This must have been Benjamin’s idea, as subsequent discussion revealed that she was not a girl who would ordinarily give, uh, testimony about herself via literary means. Ben chose Watership Down, which he had not so much read as repeatedly absorbed into his personality as a child. (Tangent: now that he is a filmmaker, if they ever remake the movie, Ben’s is the only opinion you will ever need whether you should see it.)
Ben may have suspected something was up, which is why he arranged this game to begin with. The girl asked him to read A Dog Named Kitty. This is not only from the hackneyed genre of noble-canine-croaks, it is a stunningly bad example. The dog does not die in the penultimate chapter, when he successfully fights off a wild something to save a defenseless something. The dog dies pointlessly by accident in the last chapter when a piece of pipeline falls off a truck on him. (Those darn oil companies!).
Cute as she was, the girl clearly did not have the right number of firefly blinks, which Ben reluctantly accepted. John-Adrian observed her lose her temper and hold a grudge over something small a few years later and was grateful the relationship with his brother had gone no deeper. She was not only the wrong subspecies, but a difficult person to boot.
I think the younger boys, who came here from Romania as teenagers, give off very mixed firefly blinks. Good thing they’re handsome, with very sexy accents.