Reminds me of a similar thing in developmental biology, where if you have two populations of cells, each having a slighly higher affinity for other cells of its own type, then they will very efficiently sort themselves into separate compartments. This is thought to be a pretty important mechanism in the formation and maintenance of structures in the body.
In case anyone's interested, here is a nice (if now rather old, although to be honest scientific writing was so much better back in the '90s) review on the whole business:
In which we find a paragraph describing this process:
"The selector genes do more than specify the pattern and the structures that the compartments will eventually make—they also specify, indirectly, a surface property. This property has been termed cell affinity, meaning that cells that share the same affinity, owing to the same binary code of selector genes, will intermingle during growth. There are a number of different experiments that lead to this conclusion, but perhaps the simplest is the observation that when the selector gene engrailed is removed, in vivo, from a posterior clone of cells in the wing, those cells gain anterior affinity: they now sort out from posterior cells and, if they are in contact with anterior cells, will sort into and mingle with them. Cells from neighboring compartments will have different affinities and tend to minimize their mutual contact, so that where the two compartments abut, there is a relatively straight line across which the cells do not stray."
Is true in physics as well. That's how stars are formed... Gravity is extremely weak, and so the affinity for one atom and another is extremely small, but after millions of years they still cluster together so hard sparks fly.
Back when i used to read a lot of papers, i found that i enjoyed the ones from the 90s more. I think the further you go back in time, the more honest and open scientists were in their writing; as time has gone on and academia has become more crowded and competitive, the more papers read like marketing. Authors writing in the 80s would happily admit that there were things they didn't know or hadn't proven; to do that now would be a sign of weakness.
I remember a paper from the 80s, the first one reporting the localisation of some cytoskeletal protein, vinculin or talin or something, where the authors present a set of microscope images showing that the protein is found exclusively at the ends of stress fibres (the main structural members of many kinds of cell). Great finding! And then they show a picture of a cell where it isn't, and is instead assembled into lots of little rings. The caption says that they have no idea what kind of cell it is, or why it's doing that. I just can't imagine that happening today.
In this case, this is a review paper, so that doesn't directly apply. But i think the ethos still pervades the writing; the authors are writing to explain what's known, not to advance some hypothesis or demonstrate how much they know.
In case anyone's interested, here is a nice (if now rather old, although to be honest scientific writing was so much better back in the '90s) review on the whole business:
http://www.sciencedirect.com/science/article/pii/S0092867400...
In which we find a paragraph describing this process:
"The selector genes do more than specify the pattern and the structures that the compartments will eventually make—they also specify, indirectly, a surface property. This property has been termed cell affinity, meaning that cells that share the same affinity, owing to the same binary code of selector genes, will intermingle during growth. There are a number of different experiments that lead to this conclusion, but perhaps the simplest is the observation that when the selector gene engrailed is removed, in vivo, from a posterior clone of cells in the wing, those cells gain anterior affinity: they now sort out from posterior cells and, if they are in contact with anterior cells, will sort into and mingle with them. Cells from neighboring compartments will have different affinities and tend to minimize their mutual contact, so that where the two compartments abut, there is a relatively straight line across which the cells do not stray."