Berlin plan #2: Contagious attention

As I’ve mentioned, I’ll be leading a ‘cognitive science safari’ in Berlin on 11th of July. We’ll be generating some experiences based on classic psychology experiments, experiments which tell us important things about how cities organise our perceptions.

Previously I described how I’ll be trying to revive a classic change blindness experiment. For my next trick, I plan to re-mix another classic experiment. This is one by famed social psychologist Stanley Milgram on the drawing power of crowds (Milgram et al, 1969).

We’ve all hear that nothing attracts a crowd like a crowd, but Milgram set out to systematically test this idea. Filming from a sixth floor window, Milgram arranged for collaborators to stop on a busy street and stare up at him. With the video evidence he could then record data on what proportion of passers-by would stop and join the crowd. In agreement with his classic work on obedience to authority, he found that the drawing power of crowds increased rapidly as the first few members joined.

Recently, research led by Princton’s Iain Couzin has provided an improved analysis on how this kind of shared attention spreads through a crowd (Gallup et al, 2012). Using automated tracking tools, the new research showed that people only follow the gaze of people near them, and – like traffic jams – attention tends to spread backwards in the crowd, rather than between people next to each other, or facing each other. There’s a great write-up of this research over at Ed Yong’s Discover blog: What are you looking at? People follow each other’s gazes, but without a tipping point.

One of the conclusion of Couzin’s recent study was that there wasn’t a tipping point for crowd gathering – no magic threshold where a crowd would just get bigger and bigger under its own `attentional gravity’.

Well, this sounds like a challenge to me, and I think I’ve thought of a way we can try and hack these experiments for added interest. Milgram and Couzin’s experiments both had a single crowd looking at a relatively uninteresting phenenon (Milgram filming from his window, a pair of experimenters filming surreptitiously). In Berlin, I’d like to try to plug two crowds into each other, so to speak. We’ll start off as in Milgram’s experiment, with one person looking up at the experimenter (Perhaps on the bridge overlooking Alexanderplatz – although suggestions welcome). The rest of us can watch the behaviour of passers-by: will they join the person staring up at the bridge? What kind of person will stop to have a look? How long will they stay? We’ll add more people to this crowd and should be able to see the patterns Milgram and Couzin observed: what is the effect of a bigger crowd? How far does the influence of the crowd extend?

Next, we’ll see if we can generate a self-sustained crowd by having more and more people join the experimenter on the bridge – creating two crowds watching each other, both attracting the attention of their nearby passers-by. If my reading of Iain Couzin’s research is right then there should be a stable equilibrium where the crowds reach a certain size and stop growing. If his theory is wrong, we could generate an endlessly growing crowd, driven by the power of positive feedback until it encompasses the whole population of the world – a Psychology equivalent to grey goo or one of those particle physics experiments which risks creating a black hole in the centre of Planet Earth.

Okay, so that second possibility is unlikely, but we are sure to generate a rich field in which to observe the interply of shared attention among the city-crowd. So please join me in Berlin as we travel the spectrum from science to speculation to experience in an attempt to unravel the mysteries of psychology in the city. As ever, I’m eagar to meet any readers who live in Berlin and would like to come along (or even help out). Get in touch!

Original announcement: Meet me in Berlin
Plan #1: The Change Blindness Experiment
Make sure you check out the video of the analysis technique on Iain Couzin’s page here (it’s the one where everyone in the crowd looks like they’ve got a yellow arrow protruding from their foreheads).
HT to Vaughan Bell for the phrase ‘cognitive science safari’


Gallup, A.C., Hale, J.J., Garnier, S., Sumpter, D.J.T., Kacelnik, A., Krebs, J. & Couzin, I.D. (2012) Visual attention and the acquisition of information in human crowds. PNAS, published online April 23rd, open access.

Milgram, S., Bickman, L. & Berkowitz, L. (1969) Note on the drawing power of crowds of different size. Journal of Personality and Social Psychology 13, 79–82.

7 thoughts on “Berlin plan #2: Contagious attention”

  1. As I read, I thought of a spectacle I’ve seen in my own life: people looking UP while watching one, and then the other, of the WTC towers come DOWN. I was surprised that so MANY civilians just stood and gasped, without running like hell in the opposite direction. I can understand why a “brave” and stoic cop might have stood his/her ground, but to NOT run? Fire and falling glass/bricks/people are all I need to hear my own feet clickety clicking in the opposite direction. On the other hand, I also remember telling a fellow passenger, on a bumpy flight (pre 9/11) when he was about to toss his cookies, that he “should not worry, I am a doctor.” When that damn flight finally landed in a wrong city (weather) we were given chits for dinners. At that dinner, I revealed (and I THOUGHT he already KNEW this), that I am a lawyer, not a doctor. He gasped. New experiment: what does a human DO when confronted by the mere idea that he or she is about to be ill in a public space?

    1. I call it the sci fi effect; people stopping to stare at something when they should be running. I assume it’s because something like that doesn’t seem real right away. Symptom of a movie culture, perhaps?

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