Chapter 6: Synchronisation

Synchronisation occurs when large numbers of individuals co-ordinate to act in unison. In this wide definition of the word, many different types of collective behaviour are examples of synchronisation. A highly aligned group of birds, fish or particles can be said to have synchronised their direction of movement. More commonly however, when we use the word synchronisation we are thinking about time. Bank robbers synchronise their watches before a robbery, the instruments of the orchestra are synchronised by the conductor and the sound is synchronised to the pictures in a film. It is this narrower sense of the word synchronisation I use in this chapter. How and why do behaviours become synchronised in time? Given that synchronisation is a specific type of collective behaviour it should come as no surprise that it shares many properties with systems looked at in earlier chapters of this book. In particular, and unlike with the bank robbers or the orchestra, synchronisation can be achieved without a leader or centralised control. As with other types of collective behaviour, we can also build mathematical models that describe how synchronisation emerges from individual interactions. Indeed, some of the models of synchronisation are among the most elegant models of collective behaviour and have been employed successfully in understanding a wide variety of biological and social systems.