On the commute in to work, I sometimes encounter the merge-impaired, those who have no idea how to manage a merge onto the interstate. I'm thinking the whole merge concept has only existed since the interstate system which started in the 1950's. How did engineers think that up? What made them think it would work? Were there some behavioral psychologists on the team? Merging lets us use our raptor skills. As evolved predators, we humans are insanely good at gauging trajectories of movement and points of intersection with possible food objects. Merging is a socially optimized and altruistic use of those skills. So the merge-impaired may be lacking in the raptor skills area (no racket ball for you) or they may be stuck in an older stop-then-start-again driving paradigm. Or maybe they don't see that the car is the driver's exoskeleton capable of body English; reading and sending clear intent is critical in merging. Anyhow, the History of Merging would make a good thesis for someone.