New draft: When slower is faster

The slower is faster (SIF) effect occurs when a system performs worse when its components try to be better. Thus, a moderate individual efficiency actually leads to a better systemic performance. The SIF effect takes place in a variety of phenomena. We review studies and examples of the SIF effect in pedestrian dynamics, vehicle traffic, traffic light control, logistics, public transport, social dynamics, ecological systems, and adaptation. Drawing on these examples we generalize common features of the SIF effect and suggest possible future lines of research.

When slower is faster
Carlos Gershenson, Dirk Helbing


Five postdoctoral fellowships in complex systems, UNAM

As a part of the consolidation of the National Laboratory of Complexity, the Center for Complexity Science of the National Autonomous University of Mexico is seeking outstanding candidates for five one year postdoctoral positions beginning in August, 2015. Research plans from all areas related to complex systems are encouraged.

Please send CV and research plan to cgg [at] unam.mx before June 10th.

//Please forward to whom may be interested.


New paper: Rank Diversity of Languages: Generic Behavior in Computational Linguistics

Statistical studies of languages have focused on the rank-frequency distribution of words. Instead, we introduce here a measure of how word ranks change in time and call this distribution rank diversity. We calculate this diversity for books published in six European languages since 1800, and find that it follows a universal lognormal distribution. Based on the mean and standard deviation associated with the lognormal distribution, we define three different word regimes of languages: “heads” consist of words which almost do not change their rank in time, “bodies” are words of general use, while “tails” are comprised by context-specific words and vary their rank considerably in time. The heads and bodies reflect the size of language cores identified by linguists for basic communication. We propose a Gaussian random walk model which reproduces the rank variation of words in time and thus the diversity. Rank diversity of words can be understood as the result of random variations in rank, where the size of the variation depends on the rank itself. We find that the core size is similar for all languages studied.

Cocho G, Flores J, Gershenson C, Pineda C, Sánchez S (2015) Rank Diversity of Languages: Generic Behavior in Computational Linguistics. PLoS ONE 10(4): e0121898. doi:10.1371/journal.pone.0121898

This is the first publication of an ongoing collaboration with colleagues from the Physics Institute at UNAM, there is more in the works... It has been a pleasure working with them.


Two Research Professor Positions at UNAM: Bioinformatics and Signal Processing

The Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas (IIMAS) of the Universidad Nacional Autónoma de México (UNAM) has open calls for research professor positions in bioinformatics and signal processing. This position, aimed consists of renewable one-year contracts with the possibility of tenure after three years.

The aim of these positions is to create a research group in the new campus of UNAM in Mérida, Yucatán, part of the Science and Technology Park of Yucatán.

Application deadline: April 21st.

More details (in Spanish) at the links in bold above.


Why so many Mexicans want the president to resign?

I do not think that the resignation of our president Enrique Peña Nieto would be positive in the short term. Instability probably would increase. But I want to share why so many people are asking for his resignation, also because the news are not even reaching the majority of the Mexican population.

Peña had a controversial campaign, with thousands of reported electoral irregularities . After two years in office, the violence in the country continues, and many other promises are still to be materialized.

But all this is normal Mexican politics. Previous presidents in similar situations have not met such a rejection from the national and international communities.

The straw that broke the camel's back was the dissapearance and possible murder of 43 students in the village of Ayotzinapa, in the southern state of Guerrro (Acapulco is also in that state, and was last year the 3rd most violent city in the world). The students were intecepted by the local police, there were 6 killed and 25 injured survivors. It seems that the former mayor, his wife, and the head of police were involved. They fled, were arrested a month later, but investigations are still underway.
This occurred already two months ago. The governor resigned, the president has made some declarations, but there is still huge discontent, represented in social media by the hashtag #YaMeCanse https://twitter.com/hashtag/yamecanse (IAmAlreadyTired)

On november 20th, anniversary of the Mexican Revolution, there were worldwide demonstrations. In Mexico City's main square, 11 people were arrested and have been treated as terrorists. There have been further demonstrations demanding the release of the 11 arrested.

To add insult to injury, there has been a huge scandal about a $7 million house, allegedly to the name of the president’s wife Angélica Rivera (former soap opera actress) with indicators that it was acquired with deviated public money. No investigations of course, just a video declaration which has been already used to teach how to detect when people are lying.

Perhaps the main problem is that the government, trying to control some of the media, has not made explicit declarations about what is going on. So rumors spread easily and people don't know what to believe. This lack of credibility of the Mexican government has been highlighted by major international media, while the future of the country lies in uncertainty.


Winners of the Audi Urban Future Award 2014

On November 10th, a day after the 25th anniversary of the fall of the Berlin wall, our team Living Mobilities from Mexico City was declared winner of the third edition of the Audi Urban Future Award. Together with José Castillo (team leader, watch the video from his final presentation) from Arquitectura 911 and Gabriella Gómez-Mont from the Laboratorio para la Ciudad, we were proud and delighted to be declared winners by an international jury, considering the great proposals presented by the teams from Berlin, Boston, and Seoul.

Our project proposes to create a new social contract, assisted by technology, to improve mobility not only in terms of efficiency, but also in terms of quality of life. This focusses on Mexico City, but has the potential to be extended to other megacities in Latin America, Asia, and Africa. We have a big city with small data, so we aimed at coordinating government, institutions, companies, and individuals to become "data donors". We've had considerable success, and with this opportunity we will extend our partnerships and to offer benefits, in particular to data donors, in general to the city.

The competition was very tight. Perhaps what inclined the balance in our favor was the timescale. Even when some aspects are futuristic, we arleady began implementing some of our proposals, so the impact can be much more immediate.

I am very grateful for this opportunity, for being able to participate and collaborate with a great multidisciplinary team of highly talented people. Apart from José and Gabriella, I am grateful to Mónica Arzoz, Roberto Ascencio, Stalin Muñoz, Daniel Pérez Tello, Christopher Chávez, Ricardo Mansilla, Humberto Del Ángel, Francisco Botello, José Luis Chávez, Luis Alberto Ceja. Josué López, Jaime López, Keylin Ortiz, and Jorge Tinoco. I am also grateful to the fruitful interactions with Christian Gärtner, Sophie Stigliano, Sara Mortarino, and the rest of the team at Stylepark, and also to Lisa Füting, Jutta Firsch, Annegret Maier, Rainer Stahlmann, and many other people at Audi with whom we had fruitful interactions.

OK, we won, now the hard work begins, as part of the prize involves extending the proposal into 2015. This will be an unique opportunity to explore ways in which we can improve cities, collaborating with many more partners.


Falling Walls

I was just in Berlin for the first time, for the Award Ceremony of the Audi Urban Future Award 2014 (which we won! But that will be the topic of another post). The organizers had the great idea to make the ceremony coincide with the Falling Walls Conference and the 25th anniversary of the fall of the Berlin Wall.

Incidentally, just before I was in Ensenada for another conference, and on the way to Tijuana airport our hosts took us to the border wall by the sea. That is another city marked by a wall, which although permeable, it separates and divides people. So many touching stories you can hear, I've been reflecting these days how states decisions can affect so much the life of individuals. On the other hand, the fall of the wall is an example of how individuals can change states.

A photo posted by Carlos Gershenson (@cgershen) on

I met some Germans for the first time fifteen years ago, from my generation. Whenever there was mention about the war, I perceived shame in them, even when they were born long after it occurred. I was positively impressed by the speeches these days of Angela Merkel (Angie, as the locals call her... Did we ever had a political leader in Mexico called by a tender name? ) and the Mayor of Berlin. They reflect an acceptance of their history and legacy which is not shameful, nor proud, but now an example from which we can and should learn from.

In the night of the 9th, thousands of balloons placed where the old wall was were freed into the air, a "flying wall". If I undrstood properly the speech of the mayor, these balloons represent a message of hope from Berlin to the world, so that never again a regime opresses and separates people. Ironically, now there are many more walls in the world than when the one in Berlin fell 25 years ago, mainly to prevent immigration... Hopefully we will live to see most of them come down.
A photo posted by Carlos Gershenson (@cgershen) on
This reminds me of a thought which originated during a conversation with Stu Kauffman a few months ago: "Science is moving from trying to predict Nature to dominate it, to science as a means to understand Nature and take our place in the cosmos". It seems to me that building walls we are not assuming our place, but trying to impose our stiff ideas over others, and that breaks the natural order of things, which of course leads to suffering.


New paper: Can Government Be Self-Organized? A Mathematical Model of the Collective Social Organization of Ancient Teotihuacan, Central Mexico

Teotihuacan was the first urban civilization of Mesoamerica and one of the largest of the ancient world. Following a tradition in archaeology to equate social complexity with centralized hierarchy, it is widely believed that the city’s origin and growth was controlled by a lineage of powerful individuals. However, much data is indicative of a government of co-rulers, and artistic traditions expressed an egalitarian ideology. Yet this alternative keeps being marginalized because the problems of collective action make it difficult to conceive how such a coalition could have functioned in principle. We therefore devised a mathematical model of the city’s hypothetical network of representatives as a formal proof of concept that widespread cooperation was realizable in a fully distributed manner. In the model, decisions become self-organized into globally optimal configurations even though local representatives behave and modify their relations in a rational and selfish manner. This self-optimization crucially depends on occasional communal interruptions of normal activity, and it is impeded when sections of the network are too independent. We relate these insights to theories about community-wide rituals at Teotihuacan and the city’s eventual disintegration.

Froese, T., Gershenson, C., and Manzanilla, L. R. (2014). Can government be self-organized? a mathematical model of the collective social organization of ancient teotihuacan, central mexico. PLoS ONE 9 (10) (10): e109966. http://www.plosone.org/article/info:doi/10.1371/journal.pone.0109966


Review article published: The past, present, and future of artificial life

For millennia people have wondered what makes the living different from the non-living. Beginning in the mid-1980s, artificial life has studied living systems using a synthetic approach: build life in order to understand it better, be it by means of software, hardware, or wetware. This review provides a summary of the advances that led to the development of artificial life, its current research topics, and open problems and opportunities. We classify artificial life research into 14 themes: origins of life, autonomy, self-organization, adaptation (including evolution, development, and learning), ecology, artificial societies, behavior, computational biology, artificial chemistries, information, living technology, art, and philosophy. Being interdisciplinary, artificial life seems to be losing its boundaries and merging with other fields.

Aguilar W, Santamaría-Bonfil G, Froese T and Gershenson C (2014) The past, present, and future of artificial life. Front. Robot. AI 1:8. http://dx.doi.org/10.3389/frobt.2014.00008


Paper published: Entropy Methods in Guided Self-Organisation

Self-organisation occurs in natural phenomena when a spontaneous increase inorder is produced by the interactions of elements of a complex system. Thermodynamically,this increase must be offset by production of entropy which, broadly speaking, can beunderstood as a decrease in order. Ideally, self-organisation can be used to guide the systemtowards a desired regime or state, while “exporting” the entropy to the system’s exterior. Thus, Guided Self-Organisation (GSO) attempts to harness the order-inducing potentialof self-organisation for specific purposes. Not surprisingly, general methods developed tostudy entropy can also be applied to guided self-organisation. This special issue covers a broad diversity of GSO approaches which can be classified in three categories: informationtheory, intelligent agents, and collective behavior. The proposals make another step towardsa unifying theory of GSO which promises to impact numerous research fields.

Entropy Methods in Guided Self-Organisation
Mikhail Prokopenko and Carlos Gershenson
Entropy 2014, 16(10), 5232-5241; doi:10.3390/e16105232