How a simple mathematic formula is starting to explain the bizarre prevalence of altruism in society

Why do humans cooperate in things as diverse as environment conservation or the creation of fairer societies, even when they don’t receive anything in exchange or, worst, they might even be penalized?

This is a question that has puzzled academics for centuries, especially since in evolution the basis for the “survival of the fittest” is, after all, selfishness. But in an article just published in the journal Nature, three Portuguese theoretical physicists develop a mathematical model capable of providing a way out from this conundrum through the introduction of social diversity - a ubiquitous characteristic of modern social networks - and suggesting that that the act of cooperation is dependent on one’s social context/ranking.

And in fact, when social diversity was taken into account the numbers of those cooperating increased in direct relation to the system diversity. Furthermore, cooperation, according to this model, spreads even faster when the act of cooperation is considered more important than the amount given, with these societies presenting also a much fairer distribution of wealth. This new mathematic model for society’s evolution is particularly interesting because not only it reveals a logic behind the large numbers of cooperators that we know exist in all human societies, but also it gives us a glimpse of the principles that can help “pushing” them into a better, fairer, path.

Evolutionary game theory is a mathematical approach used to study (and predict) the evolution of social interactions, in which the study of conflict and decision-making is treated – like its name indicates – as a game. One such example are public good games (or PGG), which are frequently used to study cooperation as they look into social behaviour towards public goods - such as education, free health or even street lightning – those that every one can benefit from, regardless of how much they contribute (or not) to create it.

Here because the individual’s benefits are independent of he/she contribution the most rational and selfish strategy (both in the games and real life) is to chose no-cooperation, what we know does not happen in real life. This is a good example of how difficult it has been to understand and create a theoretical model capable of explaining the emergence and prevalence of cooperation not only among humans but many other species.

What Jorge M. Pacheco and Marta D. Santos (University of Lisbon, Portugal) did - together with Francisco C. Santos (Free University of Brussels, Belgium) - in order to overcome this apparent paradox, was to introduce into PGG, for the first time, a new variant – social diversity – in contrast to the models previously used in which all individuals were equivalent. Social diversity here refers to the characteristics typical of most social networks: the existence of individuals with different numbers and types of social connections, with few very highly connected and most with very few connections.

Since PGG are represented as a mathematical formula, diversity was introduced as a new variable in the equation. Then Santos, Santos and Pacheco used this new altered formula to calculate the percentage of collaborators in the community, in function of population diversity (in PGG this would refer to the number and type of games each individual participated or, in other words, his/her “popularity”). And in fact, it was found, that in populations with high diversity, as diversity increased also did collaboration levels.

The way PGG work is that each individual pays a certain amount to play (defectors play but do not pay/cooperate) and in the end profit, which is the total amount gathered in a game, is divided by all players. The reason why diversity increased cooperation had to with the fact that those few individuals with more connections and playing more games (the cooperators) would also have much higher “profits” and their impressive success would lead the other players to imitate their behaviour (even when the behaviour per se did not seem to improve directly their own life) resulting in an exponential increase of cooperation. In the same way, in real life the more connected/popular individuals are emulated, becoming role models and opinion makers.

Equally the model also predicted that even when no-cooperators lead to new no-cooperators (as it happens many times in real life where this kind of behaviour can spread within groups) this will result in less profit, less success and eventually their own self-extinction with only a few sporadic ones left to parasite cooperators.

Furthermore, it was also shown that the increase in cooperation was particularly accelerated when all individuals contributed to the games with the same total contribution, independently of the number of games played. This corresponds, in real life, to saying that if the act of contributing to the public good was seen as more important than the amount contributed, the percentage of collaborators in a community would grew much faster.

Interestingly, the model, when applied in a more economical perspective, also suggests that these communities, with high diversity and where the act of cooperation is what matters, will also have a much fairer wealth distribution.

In conclusion, social relations, in this case differences in “popularity”, tested when introduced into PGG , are suggested to be crucial for the spread of cooperation throughout society.

Although this is obviously a very simple mathematical model and reality will never be as linear, Santos, Santos and Pacheco’s results gives us a total new perspective on how to look at ways of increasing cooperation/altruism and, consequently, also on how to create more successful societies, concerning issues as crucial to our survival as the protection of the environment or fairer social relationships, contributing in this way to the construction of a more peaceful world with less conflict and destruction.

Citation: “Social diversity promotes the emergence of cooperation in public goods games”; Nature 454, 213-216

Source: GPEARI

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Citation: How a simple mathematic formula is starting to explain the bizarre prevalence of altruism in society (2008, July 18) retrieved 15 October 2019 from
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Jul 18, 2008
Special report: We re still trying to figure out why anybody would want to live according to these unfounded ethical standards, and weve manipulated our best scientists to come up with some explanation we can spin. Results beg the question: Are we really as importaint as we think we are?

Jul 18, 2008
How this explains human evolution is given in

Jul 18, 2008
I might be being really dense here...they are saying that people are more likely to cooperate if by cooperating they themselves will get more out of it? How is this altruistic? We see this everyday in game shows, etc. where even the jerks sometimes turn around and cooperate if they know they can get more out of it. According to the article, people are cooperating more to gain social acceptance, something that benefits the non-cooperators if they begin cooperating and hence not an altruistic act.

As defined by Merriam-Webster's:
altruism 1 : unselfish regard for or devotion to the welfare of others 2 : behavior by an animal that is not beneficial to or may be harmful to itself but that benefits others of its species

From the article:
"education, free health or even street lightning"

"create more successful societies, concerning issues as crucial to our survival as the protection of the environment or fairer social relationships, contributing in this way to the construction of a more peaceful world with less conflict and destruction."

How many people would pay for their own street light that would not only benefit them but also others and not pay for a light on the other side of the country where they do not visit, have never visited, and have no relatives there? Free health is for everyone, including themselves as is education and the protection of the environment has to do with the survival of the species so that to has direct evolutionary benefits to them.

This study explains the act of cooperation and we all know that is a very far cry from altruism. I don't see how this study even remotely relates to altruism. I see how it validates the inherent selfishness of people by offering them a reward system for their behavior but I don't see how this in any way explains soldiers who leap onto grenades to save the men around them knowing that they will die. Such acts take the individual out of the genetic pool and go against every evolutionary urge. These such acts are truly altruistic.

Anyone care to explain?

Jul 18, 2008
Sorry for you losers who will object and call this an insane off the rails comment, but here goes... I just can't help myself after seeing this.

"Bizarre prevelance of altruism". hahaha HAHAHA I mean, I love the human race as much as anybody, but this is just turning a blind eye to the human condition. There is NO PREVELANCE of inherent altruism in evolution or in humanity (in and of ourselves at least). How revealing about the preconceived notions the researchers had going in. Ask anybody who lived under tyranny in any of a thousand places on the planet (or still are, where the Christian world has not gone to free them yet) and you would quickly learn what complete pap, rubbish, drivel, garbage, hogwash, BUNKUM this crap is!

...all in all though, not too bad, relatively speaking (after all, hasn't Einstein shown us all conclusively that "it is all very RELATIVE", therefore truth, and consequences, don't matter or even exist at all, right - and this is said sarcastically for you idiots who want to try to explain relativity to me now after calling me a fascist), of an article for modern "science" media (propaganda).

Jul 18, 2008
Guess I'll read the source article in Nature. This account is so poorly written and devoid of copy editing that I couldn't make sense of it. I've never read worse writing in this venue.

Jul 19, 2008
"How revealing about the preconceived notions . . . tyranny in any of a thousand places on the planet (or still are, where the Christian world has not gone to free them yet)"

Pot. Kettle.

Jul 19, 2008
how stupid is that?
cooperation gives cooperator group evolutionary advance over individuals that do not cooperate... check out trusts...

Jul 19, 2008

You poor American sap with your inane us and them propaganda instead of an education. I pity you and your horrible worldview, It's true what you say but only in the US. The rest of the world is composed of individuals and societies not ayn rand disciples and secret societies. That's why your country is being looted by a gang of psychopathic criminals and over 2 million citizens are in prison. You probably don't even have a passport.

Jul 19, 2008
"bizarre prevalence of altruism in society"?

There could be hardly any society without altruism, its not all that bizarre.

Imagine a family where the parents take all the resources and leave their children to starve with no clothes or shelter....

I happen to believe that we didn't evolve as little "individuals" but as a group, because animals that behave as group and cooperate are going to kick the ass of everything else.

Jul 20, 2008
Hey Nilbud
How does what you said contribute to the conversation at hand? I see no relevance or logic in your spouting of hate in a scientific discussion. If you want to complain somewhere perhaps you can go wander into some yahoo chat room, and leave the scientific debates to the real adults.
Thank You

Aug 28, 2008
@Shiteballsentry you are a dumb clown and that's why you don't see things which are obvious. Do keep on showing how dumb you are. You really don't understand much so perhaps you should be quiet in future.

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