Following leader not always best idea

For animals that live in social groups, and that includes humans, blindly following a leader could place them in danger.

Go your own way – or not. Depends on what everyone else is doing really

To avoid this, one groups of scientists think animals developed simple but effective behaviour to follow where at least a few of them dare to tread – rather than follow a single group member. This pattern of behaviour reduces the risk of imitating maverick behaviour of an individual as the group recognise that consensus is better than following someone that goes it alone.

Dr Ward, of the University of Sydney, led the study. He said: “Social conformity and the desire to follow a leader, regardless of cost, exert extremely powerful influences on the behaviour of social animals, from fish to sheep to humans.”

The decision of whether to follow the lead of another individual is a fundamental problem for grouping animals - leadership in an animal social group may be assumed by an individual which exhibits a directional preference according to the information it holds. This may be information about, for example, the location of food or a predator’s whereabouts.

But how do the animals identify which individuals possess pertinent information?

One plausible answer is that animals in groups only respond when they see a threshold number of fellow group members perform a particular behaviour. To test this, the team examined whether groups of fish could be led by replica individuals of the same species past a model of a predatory fish.

Dr Ward said: “Solitary test fish were prepared to follow a replica leader towards the predator model, suggesting that an isolated member of a social species will pay almost any cost to stick close to a ‘friend’. When test fish were in larger groups of 4 and of 8 fish, however, the picture was very different: a solitary replica leader was ignored. Instead, it required 2-3 replica leaders to influence these larger groups.”

By adopting this ‘quorum response’, where subjects are prepared to follow a leader only when a threshold number of individuals behave in a particular way, animals can reduce the likelihood of spreading non-adaptive following behaviour. Whereas a single, maverick individual may act irrationally in a given situation, it is far less likely that two individuals will act so strangely

Dr Ward said: “We chose to test quorum decision-making with fish because they're easier to work with, but although we tend to think that we are more complex than fish in our decision-making, the reality is that we're more similar to them than we may choose to admit!”