How do swarms of pedestrians, each with unique origins and destinations, maintain order in crowded urban environments? An article in last week’s Sunday Times explores this question and describes (but never mentions by name) the “boids” model by Craig Reynolds. In this seminal model, free-thinking computerized individuals follow just three simple rules governing their steering behavior: separation, alignment, and cohesion. Once the individuals are set into motion, these three behavioral rules are amazingly sufficient for modeling organized group movement.
Variations of this model have been used to animate realistic group movements in video games and movies, as well as to simulate animal schools, flocks, and herds in ecological studies.
What movement rules do you follow? This holiday, as you pass through city streets, airports, or shopping malls, take note of the cues that you react to unconsciously. Could it be that our steering decisions are no more complicated than those made by fish?