Self-Organization and Collective Behavior in Vertebrates

As a ripple of light the fish turn. Like some animate fluid, the school glides and turns again. The synchrony of motion is captivating. A similar integration of behavior can be seen in a bird flock. The volume and shape of the group change as the group turns and arcs overhead, and yet the aggregate remains cohesive. Many group-living vertebrates exhibit complex, coordinated, spatiotemporal patterns, from the motion of fish and birds, to migrating herds of social ungulates and patterns of traffic flow in human crowds. The common property of these apparently unrelated biological phenomena is that of interindividual interaction, by which individuals can influence the behavior of other group members. It is on how these interactions result in the collective behaviors of vertebrate animal groups that we focus here. Specifically, we consider systems in which insights from self-organization theory have been useful in improving our understanding of the underlying mechanics. Self-organization theory suggests that much of complex group behavior may be coordinated by relatively simple interactions among the members of the group. According to this theory, the form, and therefore often the function, of the collective structure is encoded in generative behavioral rules. Self-organization has been defined