Understanding how cooperation evolves and is maintained represents one of evolutionary biology's thorniest problems. This stems from the fact that freeloading cheats will evolve to exploit any cooperative group that doesn't defend itself, leading to the breakdown of cooperation. New research using the bacterium Pseudomonas fluorescens has identified a novel mechanism that thwarts the evolution of cheats and broadens our understanding of how cooperation might be maintained in nature and human societies. The new findings are reported by Michael Brockhurst of the University of Liverpool and colleagues at the Université Montpellier and the University of Oxford.

Bacteria are known to cooperate in a wide variety of ways, including the formation of multicellular structures called biofilms. P. fluorescens biofilms are formed when individual cells overproduce a polymer that sticks the cells together, allowing the colonization of liquid surfaces. While production of the polymer is metabolically costly to individual cells, the biofilm group benefits from the increased access to oxygen that surface colonization provides. However, cheating types rapidly evolve that live in the biofilm but don't produce the polymer. The presence of cheats weakens the biofilm, imperiling its survival by causing it to sink.

In the new work, the researchers studied the effect of short-term evolution of diversity within the biofilm on the success of cooperation. The researchers found that within biofilms, diverse cooperators evolved to use different nutrient resources, thereby reducing the competition for resources within the biofilm. The researchers then manipulated diversity within experimental biofilms and found that diverse biofilms contained fewer cheats and can produce larger groups than non-diverse biofilms. The findings indicate that, as in ecological communities, biodiversity within biofilms is beneficial--moreover, the authors point out that this is the first time that such ideas have been applied in the context of social evolution, and it represents a new way in which cooperation can survive in the face of cheating. Furthermore, the new work sheds light on how division of labor within multicellular organisms may initially have evolved in order to minimize functional redundancy among cells and to increase efficiency.

Brockhurst et al.: "Character Displacement Promotes Cooperation in Bacterial Biofilms." Publishing in Current Biology 16, 2030–2034, October 24, 2006 DOI 10.1016/j.cub.2006.08.068. >from *Diversity promotes cooperation among microbes*. October 23, 2006

related context
> evolutionary path. the scale-free architecture that pervades biological networks gives them an evolutionary edge by allowing them to evolve to perform new functions more rapidly. august 25, 2006
> network structure impact on behavior. the interaction between social network structure and collective problem solving. august 10, 2006
> the spatial scale of competition. 'humans behave less cooperatively when they think they are in direct 'local' competition with each other, and more cooperatively under circumstances of 'global'-scale competition.' june 5, 2006
> cheats don't always prosper. 'cheaters produce energy rapidly by quickly taking in all the sugar they can and only partially converting it into energy. while this ensures swift energy production for the individual, it is a wasteful method that reduces resources available for the group as a whole.' may 26, 2006
> why we give. 'reciprocity is arguably the foundational basis of cooperation in humans. without some kind of payback, altruism can be a very costly endeavor in small-scale societies subsisting on wild foods.' december 30, 2005
> neural basis of altruistic punishment. september 10, 2004
> cooperation evolution. october 8, 2003
> coupled oscillators. -that is, entities capable of responding to each other's signals- will spontaneously self-organize april 9, 2003
> small-world networking. february 4, 2003
> social cooperation is rewarding to the human brain. 'during the mutually cooperative social interactions, activation was noted in those areas of the brain that are linked to reward processing.' july 19, 2002
> the new science of networks. june 6, 2002
> building a free flow of knowledge. march 15, 2002
> selected essays of richard m. stallman. 2002

imago
> coop nutrients

sonic flow
> cheats and broadens [stream]
cheats and broadens [download]

openfriday@straddle3
···························
cooperative spaces
hacklab + banco común de conocimientos + universidad pirata
friday, october, 27, 2006. 20 h
straddle3. c/ riereta, 32 1-3
barcelona

Proving yet again that nature pays no attention to academic boundaries, two scientists at UCLA and the Santa Fe Institute have gained a deeper insight into rainfall patterns and atmospheric dynamics by using techniques originally developed for magnetic materials.

Physicist Ole Peters of the Santa Fe Institute and UCLA, and climatologist J. David Neelin of UCLA, argue that the onset of intense tropical rain can be described by the same mathematics as a piece of iron that's making the transition from unmagnetized to magnetized.

To illustrate the principle, explain the two scientists, imagine that you're dribbling rice grains onto a steadily accumulating mound of rice. Adding one more grain usually does nothing at all, except to make the pile a bit bigger. But eventually, as the sides of the pile get steeper, the balance becomes so precarious that a single falling grain can trigger an avalanche--sometimes even a catastrophic avalanche. At this point of "self-organized criticality," a tiny perturbation can produce a huge response.

So it is with an ordinary iron bar magnet that's near a certain critical temperature. At low temperatures, perturbations don't have much effect. Once the iron atoms in the bar have oriented themselves in the same direction, with their internal magnetic fields adding together, they like to stay that way; the bar is permanently "magnetized." But as the temperature goes up, meaning that the iron atoms are vibrating harder and harder, the disordering effects of the vibrations begin to overwhelm the forces that keep the atoms in line. At the critical temperature, the balance is so precarious that the slightest fluctuation can cause the entire magnet to switch north and south. Again, a tiny perturbation can produce a huge response.

And so it is with rainfall over the tropical oceans, explain the scientists, who based their conclusions on satellite remote sensing data. "The atmosphere has a tendency to move to a critical point in water vapor where the likelihood of rain dramatically increases," says Peters. "The system reaches a point where it's just about to rain; it's highly susceptible. Any additional water vapor can produce a large response."

One near-term payoff from this insight may be more accurate climate models, which currently have a tough time accurately representing precipitation.

"It's known that as water vapor increases" noted Neelin, "that there should be an onset of precipitation. These results tell us much more precisely how that transition occurs--which we can incorporate into atmospheric models". >from *A Link Between Rainfall and Magnetism*. They are nothing alike--except for their underlying mathematics. june 29, 2006

related context
> more information about peters and neelin research. "this is a huge step forward in self-organized criticality and critical phenomena. there really is a critical point. this is the strongest evidence for any physical self-organized critical system to really have a critical point." june 20, 2006
> self-organized criticality and scale-free properties in emergent functional neural networks. 'studies on complex systems have shown that the synchronization of oscillators, including neuronal ones, is faster, stronger, and more efficient in small-world networks than in regular or random networks.' october 9, 2006
> zero point energy of the vacuum. july 21, 2006
> disorder-induced synchronization. april 14, 2006
> synchrony: order is inevitable. april 9, 2003
> network-based movements. march 3, 2003
> smart mobs. october 3, 2002
> understanding the patterns of chaos. february 6, 2002

imago
> tales of suspense:
iron man plays a critical point as an attractor

sonic flow
> mathematical fabric of reality [stream]
mathematical fabric of reality [download]

Magnificent stone sculptures of Classic Maya culture (AD 250-900) have long fascinated archaeologists and the general public alike. But what did the scenes depicted in these monuments mean in their society? Takeshi Inomata (University of Arizona) argues that these images commonly show acts of public performance conducted by rulers, revealing the prominent role which state theater played in Maya political organization.

Analyzing plazas where many stone monuments are placed, Inomata suggests that extensive gathering places were a crucial concern in Maya city planning. The spaces were designed to accommodate all of, or a substantial part of, the entire kingdom's population.

Wearing ostentatious feathered headdresses and elaborate costumes, Maya kings danced in these large plazas in front of a large audience. These mass spectacles were occasions in which the general populace shared the experience of witnessing rulers engaged in culturally charged ritual performances, explains Inomata. However, this also meant that rulers were under constant evaluation by their subjects.

"Large-scale theatrical events gave physical reality to a community and helped to ground unstable community identities in tangible forms through the use of symbolic acts and objects," Inomata writes. "The centrality of rulers in communal events suggests that the identities of a Maya community revolved around the images of supreme political leaders. … Large gatherings also gave the elite an opportunity to impose their ideologies and cultural values on the rest of society through performances." >from *New study explores role of theater in Maya political organization*. October 2, 2006

related context
> theater
> net art as theater of the senses. a hypertour of jodi and grammatron by randall packer
> embeded semantics. 'the neural mechanisms map the actions of others onto one's own body.' october 6, 2006

imago
> the maya theater

In three new independent studies, researchers have deepened our understanding of the remarkable ability of some specialized areas of the brain to activate both in response to one's own actions and in response to sensory cues (such as sight) of the same actions perpetrated by another individual. This ability is thought to be based in the activity of so-called mirror neurons, which have been hypothesized to contribute to skills such as empathy, socialized behavior, and language acquisition. The new findings contribute to our understanding of how conceptually related instances of language and action, and sound and action, are linked in the brain, and how the brain distinguishes actions perpetrated by "self" and by "other."

Mirror neurons were first identified in the cortex of macaque monkeys: A particular subset of these neurons fire when, for example, a monkey picks up a banana, and when the monkey observes a human picking up a banana in a similar way. Mirror-neuron activity appears to be highly specific, such that a somewhat different set of mirror neurons would fire if a banana were poked, for example, rather than picked up. There is also evidence that mirror neurons link actions not only with visual stimuli, but also with other types of sensory cues. Technical limitations have impeded identification of individual mirror neurons in humans, but brain-imaging studies support the existence of these neurons.

In the new work from Lisa Aziz-Zadeh and colleagues, researchers used a brain-imaging technique to investigate how literal phrases describing actions performed by the mouth, hand, or foot influenced cortical neurons that are activated by the sight of actions being performed by mouth, hand, or foot. The researchers found a significant concordance between activation of certain cortical areas in response to linguistic descriptions and observed actions relating to the different body parts carrying out the actions. For example, when individuals read literal phrases such as "biting the peach" or "biting the banana," some brain areas activated that were also stimulated by videos of fruit being bitten. Similar findings were obtained for hand actions (for example, grasping a pen) and foot actions (for example, pressing a piano pedal). Together, the findings suggest that mirror neurons play a key role in the mental "re-enactment" of actions when linguistic descriptions of those actions are conceptually processed.

In the study reported by Christian Keysers, Valeria Gazzola, and colleagues, researchers investigated a different question: how mirror neurons might contribute to our understanding of auditory cues. Past work had shown that in monkeys, so-called auditory mirror neurons activate when monkeys perform certain actions and when they hear the same actions being performed. In the new work, the researchers report new evidence for an auditory mirror system existing in humans as well. Intriguingly, the researchers also found that of the subjects taking part in the experiment, those that scored higher on tests for empathy activated the system more strongly than those who scored lower on the empathy evaluation. While the relationship between motor mirror systems and empathy skills is far from clear, these findings are consistent with the existence of a link between the two.

Though mirror neurons appear to relate--and, potentially, equate--the actions of oneself with those of another, we are in fact highly adept at distinguishing our own actions from those of someone else. The basis for this distinction is explored in the study reported by Simone Schütz-Bosbach, Patrick Haggard, and colleagues, who used an established method--the so-called rubber-hand illusion--for experimentally manipulating the sense of body ownership.

Taken together, the findings indicate that the observation of others facilitates the motor system. The authors point out that the findings also suggest that the neural mechanisms that underlie action observation are intrinsically "social" --that the neural mechanisms map the actions of others onto one's own body, rather than initially treating all observed action (whether perpetrated by one's self or by others) as essentially neutral in ownership. These findings inform our understanding of the motor system's role in social cognition, and support previous suggestions that the motor system may have strongly influenced developments in human social evolution. >from *Mirrors in the mind: New studies elucidate how the brain reflects onto itself the actions of others*. September 18, 2006

related context
> beauty and the brain. 'what you like is a function of what your mind has been trained on. a stimulus becomes attractive if it falls into the average of what you’ve seen and is therefore simple for your brain to process. we can make an arbitrary pattern likeable just by preparing the mind to recognize it quickly.' september 26, 2006
> mental link between actions and words. 'what is the difference in our minds between talk and action?.' september 18, 2006
> mirror neurons. 'a set of neurons in the premotor area of the brain that are activated not only when performing an action oneself, but also while observing someone else perform that action.' march 11, 2005
> brain region learns to anticipate risk, provides early warnings. february 17, 2005
> others' intentions. march 5, 2004
> eye gaze direction: how the brain perceives emotion. june 13, 2003

imago
> the actions of others onto one's own body

sonic flow
> ...from those of someone else [stream]
...from those of someone else [download]