Fish move together (school) by copying one another and changing directions randomly, rather than calculating and adapting to an average route of the group, a team of scientists co-led by UNSW has shown.
In a study featured in Nature Physics, a group from Australia, India, and the UK has shed light on the behavioral dynamics that monitor alignment, or collective movement, of cichlid fish—offering new insights into the dynamics of schooling, and potentially the coordinated behavior of other creatures.
In the research, the researchers show the first experimental evidence of noise-induced ordering, which previously existed as a theoretical possibility. The interdisciplinary group of ecologists, physicists and mathematicians achieved this by combining the abilities of their scientific disciplines to combine experiments with computer simulations and evaluation.
This new model drafted contradicts the standard ‘moving average’ theories for schooling and herding behavior, which assume that the animals are capable of estimating the overall direction of the gaggle.
To study the behavioral dynamics, the researchers shot schools of 15, 30 and 60 cichlid fish, tracking their trajectories to analyze the mechanism behind alignment, or schooling.
When researchers interpret data, noise is an unrelated element that confuses and distracts from the information, like glare from the sun that one would try to remove to get a clearer photo.
In this case, Dr. Morris explains that the random copying between pairs of fish gives rise to a different noise, and is actually what drives their extremely coordinated behaviour.
This new perception marks the importance of noise, showing that noise can encode some necessary information about the behavioural dynamics of fish and other creatures.