Why being choosy is good

When it comes to picking a partner, being choosy is rewarded by cooperativeness, says a new study.

When it comes to picking a partner, being choosy is rewarded by cooperativeness, says a new study.

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The study, led by John McNamara, a professor at the University of Bristol, stated that the level of cooperation and the degree of choosiness increase together over time.

“The problem is that the process of natural selection tends to produce individuals that do the best for themselves. So why has a behaviour evolved that appears to benefit others at a cost to the individual concerned,” Nature quoted McNamara, as saying.

“In our model, an individual’s level of choosiness determines the level of cooperation demanded of its partner. If the current partner is not cooperative enough the individual stops interacting with this partner and seeks a better partner, even though finding a new partner incurs costs,” he added.

Therefore, when the time arrives to leave the current partner and seek a more cooperative one, two components are needed for this happening.

Firstly, there must be better partners in the crowd and secondly, there must be time to exploit the relationship with the new partner, which will be true for long-lived animals like humans.

If these conditions are achieved, natural selection will lead to a certain degree of choosiness evolving. And once this happens, an individual that is not cooperative will be discarded by its partner and must pay the cost of finding another partner.

Thus, cooperation can evolve from an initially uncooperative population.

In the study, the researchers considered a large population where, in each of a discrete series of time steps, pairs of individuals engage in a ‘game’ in which each individual does best by being uncooperative and letting its partner put in the hard work.

Every volunteer was characterised by two traits: a cooperativeness trait, which specifies the effort that the individual made in generating benefits available to its co-player, and a choosiness trait, which specifies the minimum degree of cooperativeness that the individual is prepared to accept from its co-player. The traits are not adjusted in response to the co-player’s behaviour and do not change over an individual’s life.

Professor Nigel Brown, Director of Science and Technology at BBSRC, said: “This is one of a number of fields where modelling studies are advancing biological science more rapidly than experiment alone can achieve.”

The study is published in Nature.