I spent three days last weekend at the magnificent WOMAD festival in Wiltshire, England, sitting in the sunshine listening to some of the world's best musicians doing their thing. It was a wonderfully therapeutic thing to do, leaving everyday worries and responsibilities behind.
But one thing none of us can leave behind is access to a toilet, and over the course of the weekend I started to become an observer of (largely) British toilet behaviour. If you have never been to a music festival I should explain that toilets are provided in specific areas, in a three-sided rectangular area. An occupied toilet is shown by a red indicator on the door and an empty toilet by a green indicator.
I started to watch how people behaved when approaching the toilets. At quiet times people could see a door with a green indicator and would go straight to one: at such times the toilet area would seem to be full of people moving in random straight lines. But when things got busier queues would form: in moderately busy times there would be a single queue and the first person would go to the next cubicle to become free, but at very busy times there would be separate queues in front of each cubicle. My wife also observed single queues forming in front of small clusters of toilets.
What was interesting to me were the transition points. When did a person or small group decide that the best strategy was to form a queue? When did queue formation stop? I reasoned that there were various factors such as the number of toilets, British social habits regarding queueing and so on.
It seemed to me that I was witnessing a complex adaptive system in action. How people behave in a situation that seems to be related to phenomena like birds flocking (which can be represented by a simple algorithm, such as in the various implementation of boids, e.g. http://processing.org/examples/flocking.html). Without any conscious decision-making, people change their behaviour in a way which suits the new situation that faces them.
Unlike me, most people were very happy in their unconscious decision-making and continued to enjoy the world music, untroubled by concerns about complexity and adaptation. What lucky people.