Herd: hard left/right/up/down

Posted by on Aug 11, 2007 in Uncategorized | 3 Comments


Nice piece again by Mark Buchanan in NS which suggests that it’s going to be possible to predict the significant and sudden changes that characterise complex systems such as human groups and societies and to do so just without mass observation.

Thanks to work by physicist Robert Wicks at Warwick University, it seems possible that simply by sampling a handful of flock/HERD members we’ll be able to spot the big changes of direction that are about to happen.

The point being that in a disordered state, an individual particle/agent’s behaviour gives little or no information about the behaviour of other particles; however, as a system approaches a phase transition, the information that one particle reveals about the others around it increases.

As Buchanan points out,

“In crowds, the precursors to a transformation from ordinary, regular movement to a dangerous, turbulent state or stampede can be detected mathematically by video analysis, but only with extensive computation on the movements of many people. The new technique could make practical detection much easier…perhaps with cameras tracking only a few individuals….in a crowd of say 1000 people, observations on as few as five people might be sufficient”

But don’t get Gladwellian about this: it’s not that the ones sampled are more influential or important than the others, it’s just something which all/most particles/agents within the system will experience as a phase transition approaches.


  1. Erin
    August 13, 2007

    Hey Mark, I was just thinking about this sort of thing after a trip to the MoMA in NY. I posted a couple ideas and observations about crowd movement in a museum. People move in a completely different manner in museum than on a sidewalk, but both are in the masses (at least here in NY). I can’t seem to find the information I’m looking for on crowd movements (by that I mean, Google doesn’t turn up anything). But this post and Mark B’s information seem to be the most similar to what I was looking for. Gracias. And maybe I need to read your book. 🙂

  2. Mark Earls
    August 13, 2007

    Thanks Erin.
    There’s lots of good stuff like this at http://www. helbing.org.
    Dirk Helbing’s brilliant on Crowd movement!

  3. rich
    August 20, 2007

    saw this picture and thought of you… (and the book, of course)