Arquivo da tag: Cooperação

Large human brain evolved as a result of ‘sizing each other up’ (Science Daily)

Date:
August 12, 2016
Source:
Cardiff University
Summary:
Humans have evolved a disproportionately large brain as a result of sizing each other up in large cooperative social groups, researchers have proposed.

The brains of humans enlarged over time thanks to our sizing up the competition, say scientists. Credit: © danheighton / Fotolia

Humans have evolved a disproportionately large brain as a result of sizing each other up in large cooperative social groups, researchers have proposed.

A team led by computer scientists at Cardiff University suggest that the challenge of judging a person’s relative standing and deciding whether or not to cooperate with them has promoted the rapid expansion of human brain size over the last 2 million years.

In a study published in Scientific Reports, the team, which also includes leading evolutionary psychologist Professor Robin Dunbar from the University of Oxford, specifically found that evolution favors those who prefer to help out others who are at least as successful as themselves.

Lead author of the study Professor Roger Whitaker, from Cardiff University’s School of Computer Science and Informatics, said: “Our results suggest that the evolution of cooperation, which is key to a prosperous society, is intrinsically linked to the idea of social comparison — constantly sizing each up and making decisions as to whether we want to help them or not.

“We’ve shown that over time, evolution favors strategies to help those who are at least as successful as themselves.”

In their study, the team used computer modelling to run hundreds of thousands of simulations, or ‘donation games’, to unravel the complexities of decision-making strategies for simplified humans and to establish why certain types of behaviour among individuals begins to strengthen over time.

In each round of the donation game, two simulated players were randomly selected from the population. The first player then made a decision on whether or not they wanted to donate to the other player, based on how they judged their reputation. If the player chose to donate, they incurred a cost and the receiver was given a benefit. Each player’s reputation was then updated in light of their action, and another game was initiated.

Compared to other species, including our closest relatives, chimpanzees, the brain takes up much more body weight in human beings. Humans also have the largest cerebral cortex of all mammals, relative to the size of their brains. This area houses the cerebral hemispheres, which are responsible for higher functions like memory, communication and thinking.

The research team propose that making relative judgements through helping others has been influential for human survival, and that the complexity of constantly assessing individuals has been a sufficiently difficult task to promote the expansion of the brain over many generations of human reproduction.

Professor Robin Dunbar, who previously proposed the social brain hypothesis, said: “According to the social brain hypothesis, the disproportionately large brain size in humans exists as a consequence of humans evolving in large and complex social groups.

“Our new research reinforces this hypothesis and offers an insight into the way cooperation and reward may have been instrumental in driving brain evolution, suggesting that the challenge of assessing others could have contributed to the large brain size in humans.”

According to the team, the research could also have future implications in engineering, specifically where intelligent and autonomous machines need to decide how generous they should be towards each other during one-off interactions.

“The models we use can be executed as short algorithms called heuristics, allowing devices to make quick decisions about their cooperative behaviour,” Professor Whitaker said.

“New autonomous technologies, such as distributed wireless networks or driverless cars, will need to self-manage their behaviour but at the same time cooperate with others in their environment.”


Journal Reference:

  1. Roger M. Whitaker, Gualtiero B. Colombo, Stuart M. Allen, Robin I. M. Dunbar. A Dominant Social Comparison Heuristic Unites Alternative Mechanisms for the Evolution of Indirect ReciprocityScientific Reports, 2016; 6: 31459 DOI: 10.1038/srep31459

Teamwork enables bacterial survival (Science Daily)

Strains of E. coli resistant to one antibiotic can protect other bacteria growing nearby

Date:
May 16, 2016
Source:
Massachusetts Institute of Technology
Summary:
Researchers have found that two strains of E. coli bacteria, each resistant to one antibiotic, can protect each other in an environment where both drugs are present.

Mutualism, a phenomenon in which different species benefit from their interactions with each other, can help bacteria form drug-resistant communities. Pictured is an artist’s interpretation of mutualism among bacteria. Credit: Jose-Luis Olivares/MIT

A new study from MIT finds that two strains of bacteria that are each resistant to one antibiotic can protect each other in an environment containing both drugs.

The findings demonstrate that mutualism, a phenomenon in which different species benefit from their interactions with each other, can help bacteria form drug-resistant communities. This is the first experimental demonstration in microbes of a type of mutualism known as cross-protection, which is more commonly seen in larger animals.

The researchers focused on two strains of E. coli, one resistant to ampicillin and the other resistant to chloramphenicol. These bacteria and many others defend themselves from antibiotics by producing enzymes that break down the antibiotics. As a side effect, this also protects cells that don’t produce those enzymes, by removing the antibiotic from the environment.

“Any time that you’re breaking down an antibiotic, there’s this potential for cross-protection,” says Jeff Gore, the Latham Family Career Development Associate Professor of Physics and the senior author of the study, which appears in the Proceedings of the National Academy of Sciences the week of May 16.

The MIT team found that, indeed, both strains could survive in an environment where both antibiotics were present, even though each was only resistant to one of the drugs. This type of situation is likely also found in the natural world, especially in soil where many strains of bacteria live together.

“Each of them is making different toxins and each of them is resistant to different toxins,” Gore says. “A lot of antibiotics are produced by microbes as part of the combat that is taking place between microorganisms in the soil.”

Gore and co-first authors Eugene Yurtsev and Arolyn Conwill, both MIT graduate students, also found that the populations of the two strains oscillate over time. Population oscillations are common in predator-prey interactions but rare in mutualistic interactions such as the cross-protection seen in this study.

Throughout their experiments, the researchers diluted the bacterial population each day by transferring about 1 percent of the population to a new test tube, to which new antibiotics were added. They found that while the total size of the bacterial population remained about the same, there were large oscillations in the relative percentages of each strain, which varied by nearly 1,000 percent over a period of about three days.

For example, if the ampicillin-resistant strain was more abundant in the beginning of a cycle, it rapidly deactivated ampicillin in the environment, allowing the chloramphenicol-resistant strain to begin growing. The ampicillin-resistant strain only began growing once the other strain had expanded enough to deactivate most of the chloramphenicol, at which point the chloramphenicol-resistant strain had already overtaken the ampicillin-resistant strain.

“The mutualism exhibits oscillations because the strain that is more abundant at the beginning of a growth cycle might end up less abundant at the end of that cycle,” Gore says.

At lower antibiotic concentrations, the bacterial population can survive in this oscillating pattern indefinitely, but at higher drug concentrations, the oscillations destabilize the population, and it eventually collapses.

Gore suspects that similar population oscillations may also be seen in natural environments such as the human gut, as bacteria exit the body along with bowel movements, or in soil as bacteria are washed away by rainfall.

Gore’s lab is now looking at this type of mutualism in bacteria living in the gut of the worm C. elegans. The researchers are also studying how these types of population oscillations can become synchronized over large geographic areas, and how migration between populations influences this synchronization.


Journal Reference:

  1. Saurabh R. Gandhi, Eugene Anatoly Yurtsev, Kirill S. Korolev, and Jeff Gore. Range expansions transition from pulled to pushed waves as growth becomes more cooperative in an experimental microbial populationPNAS, 2016 DOI: 10.1073/pnas.1521056113

‘Networked Minds’ Require Fundamentally New Kind of Economics (Science Daily)

Mar. 20, 2013 — In their computer simulations of human evolution, scientists at ETH Zurich find the emergence of the “homo socialis” with “other-regarding” preferences. The results explain some intriguing findings in experimental economics and call for a new economic theory of “networked minds”.

In their computer simulations of human evolution, scientists at ETH Zurich find the emergence of the “homo socialis” with “other-regarding” preferences. The results explain some intriguing findings in experimental economics and call for a new economic theory of “networked minds”. (Credit: © violetkaipa / Fotolia)

Economics has a beautiful body of theory. But does it describe real markets? Doubts have come up not only in the wake of the financial crisis, since financial crashes should not occur according to the then established theories. Since ages, economic theory is based on concepts such as efficient markets and the “homo economicus”, i.e. the assumption of competitively optimizing individuals and firms. It was believed that any behavior deviating from this would create disadvantages and, hence, be eliminated by natural selection. But experimental evidence from behavioral economics show that, on average, people behave more fairness-oriented and other-regarding than expected. A new theory by scientists from ETH Zurich now explains why.

“We have simulated interactions of individuals facing social dilemma situations, where it would be favorable for everyone to cooperate, but non-cooperative behavior is tempting,” explains Dr. Thomas Grund, one of the authors of the study. “Hence, cooperation tends to erode, which is bad for everyone.” This may create tragedies of the commons such as over-fishing, environmental pollution, or tax evasion.

Evolution of “friendliness”

Prof. Dirk Helbing of ETH Zurich, who coordinated the study, adds: “Compared to conventional models for the evolution of social cooperation, we have distinguished between the actual behavior – cooperation or not – and an inherited character trait, describing the degree of other-regarding preferences, which we call the friendliness.” The actual behavior considers not only the own advantage (“payoff”), but also gives a weight to the payoff of the interaction partners depending on the individual friendliness. For the “homo economicus”, the weight is zero. The friendliness spreads from one generation to the next according to natural selection. This is merely based on the own payoff, but mutations happen.

For most parameter combinations, the model predicts the evolution of a payoff-maximizing “homo economicus” with selfish preferences, as assumed by a great share of the economic literature. Very surprisingly, however, biological selection may create a “homo socialis” with other-regarding preferences, namely if offsprings tend to stay close to their parents. In such a case, clusters of friendly people, who are “conditionally cooperative”, may evolve over time.

If an unconditionally cooperative individual is born by chance, it may be exploited by everyone and not leave any offspring. However, if born in a favorable, conditionally cooperative environment, it may trigger cascade-like transitions to cooperative behavior, such that other-regarding behavior pays off. Consequently, a “homo socialis” spreads.

Networked minds create a cooperative human species

“This has fundamental implications for the way, economic theories should look like,” underlines Professor Helbing. Most of today’s economic knowledge is for the “homo economicus”, but people wonder whether that theory really applies. A comparable body of work for the “homo socialis” still needs to be written.

While the “homo economicus” optimizes its utility independently, the “homo socialis” puts himself or herself into the shoes of others to consider their interests as well,” explains Grund, and Helbing adds: “This establishes something like “networked minds”. Everyone’s decisions depend on the preferences of others.” This becomes even more important in our networked world.

A participatory kind of economy

How will this change our economy? Today, many customers doubt that they get the best service by people who are driven by their own profits and bonuses. “Our theory predicts that the level of other-regarding preferences is distributed broadly, from selfish to altruistic. Academic education in economics has largely promoted the selfish type. Perhaps, our economic thinking needs to fundamentally change, and our economy should be run by different kinds of people,” suggests Grund. “The true capitalist has other-regarding preferences,” adds Helbing, “as the “homo socialis” earns much more payoff.” This is, because the “homo socialis” manages to overcome the downwards spiral that tends to drive the “homo economicus” towards tragedies of the commons. The breakdown of trust and cooperation in the financial markets back in 2008 might be seen as good example.

“Social media will promote a new kind of participatory economy, in which competition goes hand in hand with cooperation,” believes Helbing. Indeed, the digital economy’s paradigm of the “prosumer” states that the Internet, social platforms, 3D printers and other developments will enable the co-producing consumer. “It will be hard to tell who is consumer and who is producer”, says Christian Waloszek. “You might be both at the same time, and this creates a much more cooperative perspective.”

Journal Reference:

  1. Thomas Grund, Christian Waloszek, Dirk Helbing. How Natural Selection Can Create Both Self- and Other-Regarding Preferences, and Networked Minds.Scientific Reports, 2013; 3 DOI: 10.1038/srep01480

Unesco lança campanha para ampliar cooperação pela água em 2013 (Envolverde)

20/12/2012 – 11h02

por Redação do EcoD

campanha Unesco lança campanha para ampliar cooperação pela água em 2013

A campanha é destinada ao dia e ao ano internacional da água. Foto: Divulgação

A Organização das Nações Unidas para a Educação, a Ciência e a Cultura (Unesco) lançou na terça-feira, 18 de dezembro, a campanha Ano Internacional da Cooperação pela Água 2013, destinada ao Dia (22 de março) e ao Ano Internacional da Água. A iniciativa pretende alcançar cinco objetivos:

1. Conscientizar sobre a importância, os benefícios e os desafios da cooperação em questões relacionadas à água;
2. Gerar conhecimento e construir capacidades em prol da cooperação pela água;
3. Provocar ações concretas e inovadoras em prol da cooperação pela água;
4. Fomentar parcerias, diálogo e cooperação pela água como prioridades máximas, mesmo após 2013;
5. Fortalecer a cooperação internacional pela água para abrir caminho para os Objetivos de Desenvolvimento Sustentável defendidos por toda a comunidade que trata sobre água e atendendo às necessidades de todas as sociedades.

Segundo a organização, a humanidade não pode prosperar sem a cooperação no manejo da água, e o desenvolvimento da assistência pelos recursos hídricos envolve uma abordagem que reúne fatores e disciplinas culturais, educacionais e científicas e deve cobrir diversas dimensões: religiosa, ética, social, política, legal, institucional e econômica.

A cooperação pela água assume muitas formas, desde a parceria por meio de fronteiras para o manejo de aquíferos subterrâneos e bacias fluviais compartilhadas, até o intercâmbio de dados científicos, à parceria em uma vila rural para a construção de um poço ou para o fornecimento de água potável através de redes urbanas.

O Ano Internacional de Cooperação pela Água, em 2013, deseja encorajar partes interessadas nos níveis internacional, regional, nacional e local a agir em prol do acesso aos recursos hídricos.

– Conheça a campanha –

* Publicado originalmente no site EcoD.

Violent Video Games Not So Bad When Players Cooperate (Science Daily)

ScienceDaily (Sep. 4, 2012) — New research suggests that violent video games may not make players more aggressive — if they play cooperatively with other people.

In two studies, researchers found that college students who teamed up to play violent video games later showed more cooperative behavior, and sometimes less signs of aggression, than students who played the games competitively.

The results suggest that it is too simplistic to say violent video games are always bad for players, said David Ewoldsen, co-author of the studies and professor of communication at Ohio State University.

“Clearly, research has established there are links between playing violent video games and aggression, but that’s an incomplete picture,” Ewoldsen said.

“Most of the studies finding links between violent games and aggression were done with people playing alone. The social aspect of today’s video games can change things quite a bit.”

The new research suggests playing a violent game with a teammate changes how people react to the violence.

“You’re still being very aggressive, you’re still killing people in the game — but when you cooperate, that overrides any of the negative effects of the extreme aggression,” said co-author John Velez, a graduate student in communication at Ohio State.

One study was recently published online in the journalCommunication Research, and will appear in a future print edition. The second related study was published recently in the journal Cyberpsychology, Behavior and Social Networking.

The CBSN study involved 119 college students who were placed into four groups to play the violent video game Halo II with a partner. The groups differed in whether they competed or cooperated in playing the game.

First, all participants filled out a survey about their video game history and a measure of their aggressiveness.

Those in direct competition played in multiplayer mode and were told that their task was to kill their opponent more times than they were killed.

Those in indirect competition played in single-player mode, but were told their task was to beat their opponent by getting further in the game.

In the cooperative condition, participants were told to get as far as they could through the game by working with their partner in Halo II’s cooperative campaign mode. In this case, the pair worked together to defeat computer-controlled enemies.

The final group simply filled out the measures and played the game at the end of the study. Their game playing was not recorded.

After playing the violent video game, the same pairs of participants who played with or against each other took part in a real-life game where they had the opportunity to cooperate or compete with each other.

In this game, they played multiple rounds where they were given dimes which they could keep or share with their partner. The researchers were looking to see if they engaged in “tit for tat” behavior, in which the players mirrored the behaviors of their partner. In other words, if your partner acts cooperatively towards you, you do the same for him. Tit for tat behavior is seen by researchers as a precursor to cooperation.

The results showed that participants who played the video game cooperatively were more likely than those who competed to show cooperative tendencies in this later real-life game.

“These findings suggest video game research needs to consider not only the content of the game but also how video game players are playing the game,” Velez said.

The second study, published in Communication Research, extended the findings by showing that cooperating in playing a violent video game can even unite people from rival groups — in this case, fans of Ohio State and those of their bitter rival, the University of Michigan.

This study involved 80 Ohio State students who, when they came to the lab for the experiment, were paired with a person who they thought was another student participant. In fact, it was one of the experimenters who was wearing an Ohio State t-shirt — or one from the rival University of Michigan.

One of the researchers made sure to point out the t-shirt to the student participant.

The student and confederate then played the highly realistic and violent first-person-shooter video game Unreal Tournament III together — either as teammates or as rivals.

After playing the video game, the participants played the same real-life game used in the previous study with their supposed partner, who was really one of the researchers.

They also completed tasks that measured how aggressive they felt, and their aggressive tendencies.

The results showed the power of cooperatively playing violent video games in reducing aggressive thoughts — and even overcoming group differences.

As in the first study, players who cooperated in playing the video game later showed more cooperation than did those who competed against each other.

It even worked when Ohio State participants thought they were playing with a rival from the University of Michigan.

“The cooperative play just wiped out any effect of who you were playing with,” Velez said. “Ohio State students happily cooperated with Michigan fans.”

Also, those participants who played cooperatively showed less aggressive tendencies afterwards than those who played competitively, at least at first. In fact, those who played competitively with a rival actually showed less aggression than those who played with a supporter of their own team.

“If you’re playing with a rival, and that rival is cooperating with you, that violates your expectations — you’re surprised by their cooperation and that makes you even more willing to cooperate,” Ewoldsen said.

Eventually, even those who competed with each other in the video games started cooperating with each other in the real-life games afterwards.

“The point is that the way you act in the real world very quickly overrides anything that is going on in the video games,” Ewoldsen said. “Video games aren’t controlling who we are.”

These results should encourage researchers to study not only how the content of violent video games affects players, but also how the style of play has an impact.

“What is more important: cooperating with another human being, or killing a digital creature?” Ewoldsen said.

“We think that cooperating with another human overrides the effects of playing a violent video game.”

Other authors of the CBSN paper were Cassie Eno of Waldorf College; Bradley Okdie of Ohio State’s Newark campus; Rosanna Guadagno of the University of Alabama; and James DeCoster of the University of Virginia.

Other authors of the Communication Research paper were Chad Mahood and Emily Moyer-Guse, both of Ohio State.

Journal References:

  1. J. A. Velez, C. Mahood, D. R. Ewoldsen, E. Moyer-Guse.Ingroup Versus Outgroup Conflict in the Context of Violent Video Game Play: The Effect of Cooperation on Increased Helping and Decreased Aggression.Communication Research, 2012; DOI:10.1177/0093650212456202
  2. David R. Ewoldsen, Cassie A. Eno, Bradley M. Okdie, John A. Velez, Rosanna E. Guadagno, Jamie DeCoster. Effect of Playing Violent Video Games Cooperatively or Competitively on Subsequent Cooperative Behavior.Cyberpsychology, Behavior, and Social Networking, 2012; 15 (5): 277 DOI: 10.1089/cyber.2011.0308