'Voting' method of fish

The three-spotted fish have their own way to choose to lead, but they do not vote or conduct primaries. In addition, the number of 'votes' received by candidates always has a clear difference.

A team of experts from the University of Sydney (Australia) and Uppsala University (Sweden) experimented with barramundi (Gasterosteus aculeatus). They drop two fake three-spotted fish into a real fish. Two fake children - controlled remotely - have different sizes, weights, dots and levels on the skin. All of these factors indicate what kind of health each child has. For example, a rounded belly means that the fish feed well, and darker spots on the body indicate that the fish are infected with flukes.

When they saw two fake fish, the real thorns in the pool tried to approach them both but then followed only the one with the round stomach, the symbol of good food. For fishes, when the whole herd swims by one, the fish is chosen as the leader.

A barramundi.Photo: arkive.org.

The research team increased the number of fish in the herd and found that as the number of 'voters' increased, their decision became more and more accurate. When there is only one fish that chooses the first-born, its exact percentage in choosing healthy and wiser children is 55%. This rate increased to 80% if the fish had 8 children, of which only one was wrong.

'Most triplets find differences between candidates from the beginning and some will make mistakes. Those who are wondering will observe and follow the majority, so the decision of the whole herd is always correct , 'said David Sumpter, a Uppsala University scientist.

According to David, when fish mimic the behavior of the majority, the ability to make the right decisions is greater than when they make their own decisions. The larger the number of individuals in a group of fish, the less likely it is to make mistakes.

Human court systems also operate on the same principle of co-consensus as fish. Many previous studies show that the greater the number of judges, the more accurate the decision of the jury.

Of course, the majority decision may still be inaccurate but then all individuals in the group make mistakes. 'In some of our tests, the fish are following the weaker one because most members make the wrong choice , ' David said.