Understanding how people socialize is an important thing. Darius understands it from one angle, I take another, and modern science takes a third. The third angle is the one I'd like to chat about today.
Rapper social networks have an interesting quirk. The data shows that, "unlike normal networks", the heavy-hitters don't really know each other personally.
I put "unlike normal networks" in quotes for the following reasons:
A) We have in no way plumbed all the "normal" networks.
B) We don't have comparative data for that particular element.
C) The science is brutally imprecise, thanks to its reliance on humans.
D) Rappers, like all other humans, tend to lie to make themselves look bigger.
Let's concentrate on (D).
When you want to make yourself look bigger in your subculture, what do you do? You mention that you know so-and-so, the famous guy. You worked with Feynman? You shout it out. You hang out with the Wayan brothers? You "casually" drop that into conversation. You pump up your contacts.
Everyone has the urge to do this, and most people follow that urge in one of two ways. They either blow their relationship out of proportion, or they try to have a deeper relationship. For example, a new game developer who talked with Chris Crawford might say, "yeah, I know Chris." Or he might try to become Chris' friend. Either way, he's making himself bigger by making himself close to a top dog.
Rap, however, has a slightly different culture. It has a brutally egotistic, competitive media culture. Once you are getting close to being a top dog, you distance yourself from other top dogs so they don't steal your limelight. I'm speaking out of my buttocks, here, using hearsay. But think about it. Their natural tendency would be to hang out with up-and-coming talents who aren't a threat. And when those talents rise, they'll be a conflict between the vibes of "I tought him everything he knows" and "Oh, I've totally outgrown that guy."
Unfortunately, the essay doesn't specifically state how much upper-level connectivity there is between other social networks - just other music genre networks. If we apply this yardstick to other fields, we can determine other arenas which might have an unusually high or low top-level connectivity. After all, it is important to be able to test this sort of thing - it might be, as the essay says, largely due to geography. Although that makes no sense to me.
We need to find arenas which share the "spotlight" feature. Subcultures in which the top dogs are fighting with each other for the spotlight, rather than each having spotlights of their own.
Perhaps actors have this problem? Well, that's easy enough to find out: do A-list actors of the same range tend to know each other? These have to be actors whose job opportunities would conflict: actors of approximately the same age and range. You couldn't expect job competition between Halle Berry and Tom Cruise, for example. But you might expect job competition between Halle Berry and Angelina Jolie.
Asking them is kind of difficult, not because they're not likely to answer, but because they're likely to put a good face on it. In rap, being an asshat is not considered a bad thing. But if you're an asshat actor, you aren't very well-liked.
Well, how about politicians? Unfortunately, the spotlight is too erratic for me to see what kind of effect it will have, but it seems to be the case that Democrat and Republicans fight antagonistically in the very high and very low levels of politics, but in the middle they don't seem to mind much. That could be a symptom.
Anyway, it's an interesting theory.