Selfish traits not favoured by evolution, study shows

 
Two competing white pelicans Humans and animals could not evolve in a co-operative environment by being selfish, scientists say

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Evolution does not favour selfish people, according to new research.

This challenges a previous theory which suggested it was preferable to put yourself first.

Instead, it pays to be co-operative, shown in a model of "the prisoner's dilemma", a scenario of game theory - the study of strategic decision-making.

Published in Nature Communications, the team says their work shows that exhibiting only selfish traits would have made us become extinct.

Game theory involves devising "games" to simulate situations of conflict or co-operation. It allows researchers to unravel complex decision-making strategies and to establish why certain types of behaviour among individuals emerge.

Start Quote

It's almost like what we had in the cold war, an arms race - but these arms races occur all the time in evolutionary biology”

End Quote Dr Christoph Adami Michigan State University
Freedom or prison

A team from Michigan State University, US, used a model of the prisoner's dilemma game, where two suspects who are interrogated in separate prison cells must decide whether or not to inform on each other.

In the model, each person is offered a deal for freedom if they inform on the other, putting their opponent in jail for six months. However, this scenario will only be played out if the opponent chooses not to inform.

If both "prisoners" choose to inform (defection) they will both get three months in prison, but if they both stay silent (co-operation) they will both only get a jail term of one month.

The eminent mathematician John Nash showed that the optimum strategy was not to co-operate in the prisoner's dilemma game.

Two men hugging Co-operating is key for evolution

"For many years, people have asked that if he [Nash] is right, then why do we see co-operation in the animal kingdom, in the microbial world and in humans," said lead author Christoph Adami of Michigan State University.

Mean extinction

The answer, he explained, was that communication was not previously taken into account.

The selfish gene?

DNA molecule, artwork

In 1974, Richard Dawkins published a gene-centred view of Charles Darwin's theory of natural selection.

He argued that it was not groups or organisms that adapt and evolve, but individual genes and each living organism's body was a survival machine for its genes.

Prof Andrew Coleman from Leicester University explains that this new work suggests that co-operation helps a group evolve, but does not argue against the selfish gene theory of evolution.

Rather, he adds, it helps selfish genes survive as they reap the awards of inhabiting co-operative groups.

"The two prisoners that are interrogated are not allowed to talk to each other. If they did they would make a pact and be free within a month. But if they were not talking to each other, the temptation would be to rat the other out.

"Being mean can give you an advantage on a short timescale but certainly not in the long run - you would go extinct."

These latest findings contradict a 2012 study where it was found that selfish people could get ahead of more co-operative partners, which would create a world full of selfish beings.

This was dubbed a "mean and selfish" strategy and depended on a participant knowing their opponent's previous decision and adapting their strategy accordingly.

Crucially, in an evolutionary environment, knowing your opponent's decision would not be advantageous for long because your opponent would evolve the same recognition mechanism to also know you, Dr Adami explained.

This is exactly what his team found, that any advantage from defecting was short-lived. They used a powerful computer model to run hundreds of thousands of games, simulating a simple exchange of actions that took previous communication into account.

Man in a jail A previous study found that selfish strategies were favourable

"What we modelled in the computer were very general things, namely decisions between two different behaviours. We call them co-operation and defection. But in the animal world there are all kinds of behaviours that are binary, for example to flee or to fight," Dr Adami told BBC News.

"It's almost like what we had in the cold war, an arms race - but these arms races occur all the time in evolutionary biology."

Social insects

Prof Andrew Coleman of Leicester University, UK, said this new work "put a brake on over-zealous interpretations" of the previous strategy, which proposed that manipulative, selfish strategies would evolve.

"Darwin himself was puzzled about the co-operation you observe in nature. He was particularly struck by social insects," he explained.

"You might think that natural selection should favour individuals that are exploitative and selfish, but in fact we now know after decades of research that this is an oversimplified view of things, particularly if you take into account the selfish gene feature of evolution.

"It's not individuals that have to survive, its genes, and genes just use individual organisms - animals or humans - as vehicles to propagate themselves."

"Selfish genes" therefore benefit from having co-operative organisms.

 

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  • rate this
    +61

    Comment number 260.

    Not long ago I remember watching a documentary about human evolution and about co-operation but it also showed that human children tended to share equally the spoils when they co-operated with each other to get the prize.

    Sharing and sharing equally is important otherwise the co-operation tends to stop.

    one only has to look at the resentment that follows when someone takes more than their share

  • rate this
    +11

    Comment number 192.

    Advancing your family/town/nation rather than just yourself is an evolutionary necessity & a sign of developed intelligence in that you understand that not only do you benefit, but so do all people you care about.

    Thinking only of yourself is a recipe for failure in evolutionary terms. History is littered with examples of such setbacks & the great societies are the ones that acted in unison.

  • rate this
    +19

    Comment number 122.

    I have actually played the simulation that's described in business school, in '96. Outcome was in line with those described in your article: paired with a classmate I did not know beforehand, we managed to build trust and stuck to cooperation despite growing temptations to cheat built in the exercise. We won the game by a huge margin. The less cheerful bit? We were the only pair to have done so.

  • rate this
    +30

    Comment number 55.

    You cannot make judgements on evolution based on a modern day experimentation, it ignores 99.99% of human development. Clearly prehistoric survival presented a balance of opportunities for selfishness and co-operation, or one or other would have been bred out of us long ago.

  • rate this
    -3

    Comment number 31.

    This all seems a bit of a mess.

    Evolution is based on the BEST genes surviving.

    An individuals goal is to selfishly ensure that their genes survive. At the same time the individual has to survive long enough to mate and as a species the more we cooperate the more likely we are to survive long enough.

 

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