Those of you who have ever attended a ‘Fête Nos’, a typical Brêton festival-type of gathering with music and people dancing, may immediately understand what I’m going to write about. All the others who have attended another gathering of a large number of people will also be completely familiar with my revived curiosity in a specific subject: The collectivity of human behavior and its occurrence in large masses of people.

Every time the music starts at a crowded ‘Fête Nos’, something peculiar happens: within seconds the mass of people all talking to each other and walking seemingly random suddenly are dancing all together in familiar patterns. This pattern is way too complex to be laid upon all those people: it must, somehow, emerge from the individual moves these people make. Interesting and intriguing, don’t you think?

Even before I started studying sociology I had read `Critical Mass’ (2004) by Philip Ball. I loved this overview of popular science and still do, but somehow it had moved to the back of my memory. I remembered the actor- or boid-based simulations, but I did not really understand how this could be related to the theory-driven sociology that I was studying. I recognized the possibilities offered by the described simulation techniques, but saw them as theories, rather than empirical tests: we can easily make assumptions about behavior and simulate the consequences of that, but then we still don’t know if these assumed behaviors indeed exist and happen in reality.

This all changed when I read `Dissecting the Social’ (2005) by Peter Hedström last year. In this seminal work, he combines a variant of rational action theory with agent based simulation models. Subsequently, he argues that these models can and should be empirically calibrated, using the outcomes of (regression) analyses and survey data. In this manner, the simulation model do no longer function as a (very explicit) form of theory, but as an actual test. This test is mainly focused on the question whether the found individual level relationships and behavior indeed can bring about the emergent social effects that are the focus of many sociological studies.

Re-invigorated regarding the use of simulation models, I recently bought `Micromotives and Macrobehavior’ by the 2005 Nobel Price laureate Thomas Schelling. I had played around with a segregation-simulation of my own, so I was interested in his famous work on this. His well-known opening passage made clear to me how easy it is to connect simulations to empirical observations. Schelling describes how he was to give a lecture to a large audience. To his amazement, he finds the first 12 rows to be empty, but the back 24 rows to be completely filled. He questions whether this has happened purposely (which it hadn’t), or whether this emerged from individual choices. On the first page of his book he is already theorizing and doing empirical ‘tests’ by asking the organizer of the lecture questions on the behavior of the people in the audience while they entered the auditorium. So, in his 1978 book, Thomas Schelling was already combining agent-based models with empirical observations.

It came all full circle when I realized what an important article Schelling wrote on his segregational models. When we understand that these agent-based models can easily be tested empirically, the fact that this isn’t done on every occasion is no longer valid criticism on the technique in general. Observing severe ethnic residential segregation, Thomas Schelling developed a theoretical model on how this might be brought about a subsequent individual choices. By simulating this model, he showed that only very slight preferences are needed to allow the emergence of severe segregation. The hypothetical statement a distinction needs to be made between large outcomes with minor causes, is quite an achievement for one article. To top that: it is easily testable by doing the right observations!

The scientific community wouldn’t be itself if it hadn’t brought forward such an empirical test. And indeed, amongst others, Ruofff and Schneider (2006) performed such an empirical test on segregation in the classroom. Deriving explicit and easily testable hypotheses from theory, these authors use a combination of seating observations and data from questionnaires to confirm the general premise of segregation theory: students of a kind sit together.

So, what does this come down to? Basically, I found it interesting to learn how I revalued a book on social theory and analysis that I read some years ago based on work I read more recently. The combination of these works does also show that the general critique on the artificiality of simulation models does not hold, for when described clearly, it is easy to write out testable hypotheses. Most intriguing to is to find that this has all been there for all that time, from the first page in Schellings book.

Schelling, T. (1971). Dynamic Models of Segregation. Journal of Mathematical Sociology
Ruoff, G. (2006). Segregation in the Classroom: An Empirical Test of the Schelling Model. Rationality and Society, 18(1), 95-117. DOI: 10.1177/1043463106060154

But, besides on an analytical level, theoretically some interesting mistakes sometimes are made, even to this day. On the other hand, properly distinguishing between individual and society leads to propositions as `individual rationality leads to collective irrationality’. Because individual people tend to set their own individual goals, a collective of people fail to reach goals that individuals cannot reach on their own. For instance, we all want to live in a less polluted environment, but when it rains, most of us are triggered to use a car instead of a bike. We reason for ourselves “what does this one small drive do to the environment compared to every other polluter?”, or even “If I come at work all rained down every autumn day, the other who uses his car (and even lives a shorter distance from work!) might get my promotion!” One of the very few ways to (actively) bring collective change about, is by `forcing’ every individual into some mode of behavior, for instance by means of legislation.

Nevertheless, we tend to think of humans as (somewhat) rational: we set goals, often influenced by self-interest, and think about means to reach our goals. On an individual level that is. Most animals are not regarded as rational. For instance, the behavior of `simple’ animals as ants are to a very large extent regulated by genetics and communication through pheromones. Reacting largely directly on the influences from the environment is perhaps not the best example of rationality indeed.

So the ants are not (all that much) rational. But does this mean that they cannot reach collective goals? For some reason, since last weekend I tend to think that their individual irrationality is very well capable of producing collective rational action. In the movie I saw this weekend (see below), a magnificent megalopolis is build by ants. No way that a central `organization’ or leader ant has planned this. So, somehow, their individual `irrationality’, their basic reacting to stimuli based on a genetic predisposition, has lead to a magnificent example of collective rationality!

I’d say the we are in dire need of reversing to proposition “individual rationality leads to collective irrationality” and add “individual irrationality leads to collective rationality” to our knowledge of existing `social’ processes.