Winnie Poel (Personal webpage )

Institute for Theoretical Biology, Humboldt Universität zu Berlin, Berlin, Germany
Living systems such as neural networks or animal groups process information about their environment via the dynamics of many interacting units and show transitions between sets of distinct macroscopic behaviors. While many studies focus on the idea that for biological systems being close to such a transition (or critical point) optimally manages a trade-off between desired functions of the macroscopic behaviors it separates, or that it yields optimal computational abilities, little attention has been given to the fact that the `optimal' configuration will depend on the environmental context. Here, we combine experimental evidence and computer simulations to show that for escape waves in schooling fish the distance to a critical point is changed via a modulation of school density according to group members' perceived risk of the environment. We find that the observed escape waves are spreading subcritically making the schools collective response less sensitive to cue intensity but more robust towards false alarms than at the critical school density.