The domino effect in collective decisions of schools of fish

01 October 2018 par webmaster
The study of mechanisms for coordinating the movement and propagation of information in schools of fish or flocks of birds, for example in the event of predator attacks, is essential to understanding the benefits of group living.

The researchers studied and modelled the propagation of information in schools of fish when they collectively change the direction of their movement.

The results, published on 25 April 2018 in the Proceedings of the Royal Society B, show that each fish mimics the behaviour of a small number of its neighbours and that this mechanism spreads from one person to another in the manner of a domino effect.

Collective movements of groups of animals are one of the most spectacular phenomena observed in nature, but the rigorous analysis of these phenomena is very recent and has only been made possible by technological advances in data acquisition and processing. These collective movements result from local interactions between individuals and are accompanied by the formation of large-scale spatial and temporal structures. They play a fundamental role in group defense, reproduction, or foraging, improving individuals’ ability to survive. To understand these collective phenomena, it is important to characterize the dynamics of interactions between individuals in a group.

Researchers from the CRCA-CBI in Toulouse, the Normal University in Beijing, and the University of Groningen in the Netherlands have studied a tropical fish species, the red nose (Hemigrammus rhodostomus), whose schooling behaviour is very pronounced.

“Social conformity and propagation of information in collective U-turns of fish schools”
Lecheval V, Jiang L, Tichit P, Sire C, Hemelrijk CK, Theraulaz G.
Proc Biol Sci. 2018 Apr 25 ;285(1877). pii : 20180251. doi : 10.1098/rspb.2018.0251.

Researcher contact
Guy Theraulaz