Crying Over Spilled Beer

Yesterday, I was at Sunset Junction, a street fair/concert held every year in Silverlake here in LA, and, in keeping with my typical concert experiences, it was jostle city. The worst offender was a girl who knocked directly into my beer hand - actually my beer elbow - when I was mid-sip. She did apologize profusely, but the damage was done.

I was there with a friend who remarked that he felt like a magnet for the walking routes that spontaneously develop in crowds - I felt (and feel) the same way. I wonder what percentage of people feel this way. While that kind of poll would be susceptible to distortion - people tend to overreport complaints, for example on review sites like yelp.com - I don't think everyone feels this way. So I think you can make a case that MWR (magnets for walking routes) really do exist.

A brief survey (i.e. a half hour of googling) tells you that while there is quite a bit of scholarship devoted to what's called "self organizing" among pedestrians, there isn't much about the spontaneous development of pathways through a stationary crowd. There are, however, a couple vocabulary words/phrases from this research that may bear on concert crowd issue. The predicted disutility of walking is sort of a governing principle of pedestrian behavior. It's a fairly simple cost-benefit idea - things like acceleration and collisions are assigned a negative value, and pedestrians tend to literally take the path of least resistance. Lanes of more or less fixed speeds are spontaneously generated and get layered together. If you want to switch lanes, you weigh the lateral acceleration you'll have to make, and the risk of a collision, against the annoyance of being stuck behind a slow person. (Interestingly, in cross-directional traffic, lateral acceleration is penalized more heavily than longitudinal - this means if two pedestrians are on perpendicular paths, they'd rather slow down than veer to avoid a collision.) The other useful vocab is empty zone. This is the amount of space you prefer to have between yourself and the walker in front of you. Empty zone is affected by speed, of course, but also personal preferences about closeness to other people. The mean empty zone is 1.4 seconds (they try to factor out speed, I guess).

These two concepts can explain MWRs at concerts. First, an MWR probably has a relatively large empty zone, due to an overall unwillingness to be too close to people. If someone is too close an MWR, s/he will tend to shift away. And once you shift, it's on - especially if the destination of the Aggressive Concertgoer is a popular one, like "close to the stage" or "port-o-potties," because there will be other people trying to get through the crowd to get to those destinations too, and by shifting and letting one guy go by, you've now presented them with a low acceleration option. Their alternative - trying to forge their own path through stationary concertgoers, who perhaps feel they have nothing to prove by going "up close" - is costly in terms of acceleration and risk of collision.

If you are an MWR, you could try not shifting, or maybe some aggressive eye contact. I hope there is an enterprising Pickle reader who conducts this experiment. As for me, I'd rather shift.