Models of Collectivity

Couzin et al. identified four collective dynamical behaviors as illustrated in the below figure:

Several models of collective behavior: (a) swarm (b) torus (c) dynamic parallel group and (d) highly parallel group.

• Swarm: An aggregate with cohesion, but a low level of polarization (parallel alignment) among members.
• Torus: Individuals perpetually rotate around an empty core (milling). The direction of rotation is random.
• Dynamic Parallel Group: The individuals are polarized and move as a coherent group, but individuals can move throughout the group and density and group form can fluctuate.
• Highly Parallel Group: Much more static in terms of exchange of spatial positions within the group than the dynamic parallel group and the variation in density and form is minimal.

The main question that should be asked is the following: How can social insects, as well as other animals coordinate their actions ti achieve an astonishing global system-level behavior? This leads us to see and study a very important concept in swarm intelligence, it's Self-Organization in the next post.